:root {
    /* Hello Kitty Soft Pink Palette */
    --primary-color: #ED0D92;
    /* Hello Kitty Bow Red/Pink */
    --primary-hover: #D10984;
    --secondary-color: #FFE4E6;
    /* Soft Pink Backdrop */
    --bg-color: #FFF0F5;
    /* Hello Kitty Light Pink - Lavender Blush */
    --bg-gradient-start: #FFF0F5;
    --bg-gradient-end: #FFE4E6;
    --sidebar-bg: #FFFFFF;
    --card-bg: #FFFFFF;
    --text-primary: #2C3E50;
    --text-secondary: #5F6C7B;
    --border-color: #FADADD;
    --input-bg: #F8F9FA;
    --success-color: #2ECC71;
    --warning-color: #F1C40F;
    --error-color: #E74C3C;

    --shadow-sm: 0 1px 2px rgba(237, 13, 146, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(237, 13, 146, 0.1), 0 2px 4px -1px rgba(237, 13, 146, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(237, 13, 146, 0.1), 0 4px 6px -2px rgba(237, 13, 146, 0.05);

    --sidebar-width: 340px;
    --header-height: 64px;
    --radius: 12px;
}

[data-theme="dark"] {
    --primary-color: #FF69B4;
    --primary-hover: #FF1493;
    --secondary-color: #2D3748;
    --bg-color: #1A202C;
    --bg-gradient-start: #1A202C;
    --bg-gradient-end: #2D3748;
    --sidebar-bg: #2D3748;
    --card-bg: #2D3748;
    --text-primary: #F7FAFC;
    --text-secondary: #A0AEC0;
    --border-color: #4A5568;
    --input-bg: #4A5568;
    --success-color: #68D391;
    --warning-color: #F6E05E;
    --error-color: #FC8181;

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
}

* {
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

body {
    font-family: 'Noto Sans SC', 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 50%, var(--bg-color) 100%);
    background-attachment: fixed;
    color: var(--text-primary);
    margin: 0;
    padding: 0;
    height: 100vh;
    overflow: hidden;
    line-height: 1.6;
}

@supports (height: 100dvh) {
    body {
        height: 100dvh;
    }
}

/* Layout */
.app-container {
    display: flex;
    height: 100%;
    width: 100%;
    position: relative;
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background: var(--sidebar-bg);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    position: absolute;
    left: -100%;
    top: 0;
    bottom: 0;
    z-index: 1000;
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: var(--shadow-lg);
    transform: translateX(0);
    /* Default open on desktop if not closed */
}

/* Desktop: Toggled Closed */
.sidebar.closed {
    margin-left: calc(-1 * var(--sidebar-width));
    /* On desktop, we want it to move off-canvas relative to flow, 
        or we use transform. If we use transform, we must handle the main-content margin.
        Let's perform a dual update:
        1. Sidebar transforms -100%
        2. Main content margin becomes 0
        But the current layout uses position: absolute for sidebar in CSS structure?
        Wait, style.css line 110 says `position: absolute`.
        If it's absolute, it overlays or pushes?
        Line 104 says `.sidebar` width 340px.
        Line 345 `.main-content` margin-left 0?
        
        Let's redefine the layout strategy for robust switching:
        Desktop:
        - Sidebar: relative (takes space) OR fixed/absolute with main-content padding.
        - Common pattern: Sidebar fixed left. Main margin-left = sidebar width.
        
        Refactored approach below:
     */
}

/* Mobile: Toggled Open */
.sidebar.mobile-open {
    transform: translateX(0);
    box-shadow: var(--shadow-lg);
}

.sidebar-header {
    height: var(--header-height);
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--border-color);
    background: linear-gradient(to right, #fff, #fff9fc);
}

.brand {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 700;
    font-size: 1.15rem;
    color: var(--text-primary);
    letter-spacing: -0.02em;
}

.brand-icon {
    width: 28px;
    height: 28px;
    filter: drop-shadow(0 2px 4px rgba(237, 13, 146, 0.2));
}

.sidebar-actions {
    display: flex;
    gap: 8px;
    align-items: center;
}

.new-chat-btn {
    color: var(--primary-color);
    background: rgba(237, 13, 146, 0.1);
    border-radius: 50%;
    width: 32px;
    height: 32px;
}

.new-chat-btn:hover {
    background: var(--primary-color);
    color: white;
    transform: rotate(90deg);
}

/* Chat Area */
.chat-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    background: #FAFAFA;
}

.messages {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 16px;
    scroll-behavior: smooth;
}

.message {
    max-width: 90%;
    font-size: 0.95rem;
    line-height: 1.6;
    animation: fadeIn 0.3s ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.ai-message {
    align-self: flex-start;
}

.ai-message .message-content {
    background-color: white;
    color: var(--text-primary);
    padding: 14px 18px;
    border-radius: 2px 16px 16px 16px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
}

/* Markdown Styling within AI Messages */
.message-content h1,
.message-content h2,
.message-content h3 {
    margin-top: 0.5em;
    margin-bottom: 0.5em;
    font-weight: 600;
    color: var(--text-primary);
}

.message-content h1 {
    font-size: 1.4em;
}

.message-content h2 {
    font-size: 1.25em;
}

.message-content h3 {
    font-size: 1.1em;
}

.message-content p {
    margin: 0.5em 0;
}

.message-content ul,
.message-content ol {
    padding-left: 1.5em;
    margin: 0.5em 0;
}

.message-content li {
    margin-bottom: 0.25em;
}

.message-content strong {
    color: var(--primary-color);
    font-weight: 600;
}

.message-content code {
    background: #f1f5f9;
    padding: 2px 4px;
    border-radius: 4px;
    font-family: 'Consolas', monospace;
    font-size: 0.9em;
    color: #e83e8c;
}

.message-content pre {
    background: #1e293b;
    color: #e2e8f0;
    padding: 12px;
    border-radius: 8px;
    overflow-x: auto;
    margin: 0.5em 0;
}

.message-content pre code {
    background: transparent;
    color: inherit;
    padding: 0;
}

.message-content blockquote {
    border-left: 4px solid var(--primary-color);
    margin: 0.5em 0;
    padding-left: 1em;
    color: var(--text-secondary);
    background: var(--secondary-color);
    padding: 8px 12px;
    border-radius: 4px;
}

.message-content hr {
    display: none;
}

.auth-modal {
    z-index: 3000;
}

.auth-header {
    background: linear-gradient(135deg, #FFF0F5 0%, #FFFFFF 100%);
}

.auth-body {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.auth-subtitle {
    font-weight: 700;
    color: var(--text-primary);
}

.auth-tip {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.5;
}

.auth-pin-input {
    width: 100%;
    border: 1px solid var(--border-color);
    border-radius: 14px;
    padding: 14px 16px;
    font-size: 1.6rem;
    text-align: center;
    letter-spacing: 0.5em;
    background: #FFFFFF;
    color: var(--text-primary);
    box-shadow: 0 1px 2px rgba(15, 23, 42, 0.06) inset;
    outline: none;
}

.auth-pin-input:focus {
    border-color: rgba(237, 13, 146, 0.6);
    box-shadow: 0 0 0 4px rgba(237, 13, 146, 0.12);
}

.auth-modal-content.shake {
    animation: authShake 0.35s ease-in-out;
}

@keyframes authShake {
    0% { transform: translateX(0); }
    20% { transform: translateX(-10px); }
    40% { transform: translateX(10px); }
    60% { transform: translateX(-8px); }
    80% { transform: translateX(8px); }
    100% { transform: translateX(0); }
}

body.auth-locked .app-container {
    filter: blur(6px);
    pointer-events: none;
    user-select: none;
}

@media (max-width: 480px) {
    .auth-pin-input {
        font-size: 1.45rem;
        letter-spacing: 0.4em;
    }
}

.user-message {
    align-self: flex-end;
}

.user-message .message-content {
    background-color: var(--primary-color);
    color: white;
    padding: 12px 18px;
    border-radius: 16px 16px 2px 16px;
    box-shadow: 0 2px 8px rgba(237, 13, 146, 0.2);
}

.input-area {
    padding: 20px;
    border-top: 1px solid var(--border-color);
    display: flex;
    gap: 12px;
    background: white;
    align-items: flex-end;
}

.input-area textarea {
    flex: 1;
    padding: 12px 16px;
    border: 1px solid var(--border-color);
    border-radius: 24px;
    outline: none;
    font-family: inherit;
    font-size: 0.95rem;
    transition: all 0.2s;
    background: #F8F9FA;
    resize: none;
    height: 48px;
    /* Initial height */
    line-height: 1.5;
}

.input-area textarea:focus {
    border-color: var(--primary-color);
    background: white;
    box-shadow: 0 0 0 3px rgba(237, 13, 146, 0.1);
}

.send-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.2s;
    flex-shrink: 0;
}

.send-btn:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(237, 13, 146, 0.3);
}

.send-btn:active {
    transform: translateY(0);
}

/* Main Content */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    height: 100%;
    margin-left: 0;
    transition: margin-left 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    background: white;
    position: relative;
    z-index: 1;
}

.top-bar {
    height: var(--header-height);
    display: flex;
    align-items: center;
    padding: 0 24px;
    border-bottom: 1px solid var(--border-color);
    justify-content: space-between;
    background: white;
    gap: 16px;
}

/* Tab Navigation */
.tab-navigation {
    display: flex;
    gap: 8px;
    background: #F8FAFC;
    padding: 4px;
    border-radius: 12px;
}

.tab-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    border: none;
    background: transparent;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.2s ease;
}

.tab-btn:hover {
    background: rgba(237, 13, 146, 0.1);
    color: var(--primary-color);
}

.tab-btn.active {
    background: white;
    color: var(--primary-color);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.tab-btn svg {
    width: 18px;
    height: 18px;
}

.view-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    height: calc(100% - var(--header-height));
}

.calendar-wrapper {
    flex: 1;
    overflow: hidden;
    position: relative;
    display: flex;
    flex-direction: column;
}

/* Custom Calendar Header */
.calendar-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 20px;
    background: linear-gradient(135deg, #FFF0F5 0%, #FFFFFF 100%);
    border-bottom: 1px solid #FADADD;
    border-radius: 16px 16px 0 0;
}

.calendar-nav {
    display: flex;
    gap: 8px;
}

.nav-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border: none;
    background: white;
    border-radius: 12px;
    cursor: pointer;
    color: var(--text-secondary);
    transition: all 0.2s ease;
    box-shadow: 0 2px 8px rgba(237, 13, 146, 0.08);
}

.nav-btn:hover {
    background: var(--primary-color);
    color: white;
    transform: scale(1.05);
    box-shadow: 0 4px 12px rgba(237, 13, 146, 0.25);
}

.nav-btn:active {
    transform: scale(0.95);
}

.calendar-title {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-primary);
    text-align: center;
    flex: 1;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.calendar-views {
    display: flex;
    gap: 6px;
    background: white;
    padding: 4px;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(237, 13, 146, 0.08);
}

.view-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2px;
    padding: 8px 14px;
    border: none;
    background: transparent;
    border-radius: 10px;
    cursor: pointer;
    color: var(--text-secondary);
    font-size: 0.7rem;
    font-weight: 500;
    transition: all 0.2s ease;
}

.view-btn svg {
    opacity: 0.7;
    transition: opacity 0.2s ease;
}

.view-btn:hover {
    background: #FFF0F5;
    color: var(--primary-color);
}

.view-btn:hover svg {
    opacity: 1;
}

.view-btn.active {
    background: var(--primary-color);
    color: white;
    box-shadow: 0 2px 8px rgba(237, 13, 146, 0.3);
}

.view-btn.active svg {
    opacity: 1;
}

/* Hide default FullCalendar toolbar */
.fc-toolbar {
    display: none !important;
}

/* Make calendar take remaining space */
.fc {
    flex: 1;
}

.students-wrapper {
    flex: 1;
    padding: 24px;
    overflow-y: auto;
    background-color: rgba(255, 255, 255, 0.5);
    backdrop-filter: blur(10px);
}

/* Student Cards */
.students-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}

.student-card {
    background: white;
    border-radius: 16px;
    padding: 20px;
    box-shadow: 0 2px 12px rgba(237, 13, 146, 0.08);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.student-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--student-color, var(--primary-color));
}

.student-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(237, 13, 146, 0.15);
}

.student-header {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 16px;
}

.student-avatar {
    width: 56px;
    height: 56px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--student-color, var(--primary-color)) 0%, rgba(255, 255, 255, 0.2) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
    flex-shrink: 0;
}

.student-info {
    flex: 1;
}

.student-name {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.student-grade {
    font-size: 0.85rem;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 4px;
}

.student-details {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.student-detail-item {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    font-size: 0.9rem;
}

.student-detail-icon {
    width: 32px;
    height: 32px;
    border-radius: 8px;
    background: #F8FAFC;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
    flex-shrink: 0;
}

.student-detail-content {
    flex: 1;
}

.student-detail-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-bottom: 2px;
}

.student-detail-value {
    font-weight: 500;
    color: var(--text-primary);
    word-break: break-word;
}

.student-detail-value.clickable {
    cursor: pointer;
    color: var(--primary-color);
}

.student-detail-value.clickable:hover {
    text-decoration: underline;
}

.student-progress {
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
}

.student-progress-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
    display: flex;
    justify-content: space-between;
}

.student-progress-bar {
    height: 6px;
    background: #F1F5F9;
    border-radius: 3px;
    overflow: hidden;
}

.student-progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--student-color, var(--primary-color)), #FF69B4);
    border-radius: 3px;
    transition: width 0.3s ease;
}

.student-actions {
    display: flex;
    gap: 8px;
    margin-top: 16px;
}

.student-actions button {
    flex: 1;
    padding: 8px 12px;
    border-radius: 8px;
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    border: 1px solid var(--border-color);
    background: white;
    color: var(--text-secondary);
}

.student-actions button:hover {
    background: #F8FAFC;
    color: var(--text-primary);
}

.student-actions button.edit-btn:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.student-actions button.delete-btn:hover {
    background: var(--error-color);
    color: white;
    border-color: var(--error-color);
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-secondary);
}

.empty-state svg {
    width: 80px;
    height: 80px;
    margin-bottom: 16px;
    opacity: 0.5;
}

.empty-state h3 {
    margin: 0 0 8px 0;
    color: var(--text-primary);
}

.empty-state p {
    margin: 0;
    font-size: 0.9rem;
}

/* Sidebar Overlay */
.sidebar-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.4);
    z-index: 900;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s;
    backdrop-filter: blur(2px);
}

.sidebar.mobile-open+.sidebar-overlay {
    opacity: 1;
    pointer-events: auto;
}

/* Calendar Customization */
.fc {
    font-family: 'Noto Sans SC', sans-serif !important;
}

.fc-toolbar-title {
    font-size: 1.35rem !important;
    font-weight: 700 !important;
    color: var(--text-primary);
}

.fc-button-primary {
    background-color: white !important;
    color: var(--text-secondary) !important;
    border: 1px solid var(--border-color) !important;
    font-weight: 600 !important;
    box-shadow: var(--shadow-sm) !important;
    padding: 8px 16px !important;
    border-radius: 8px !important;
}

.fc-button-primary:hover,
.fc-button-primary.fc-button-active {
    background-color: #FFF0F5 !important;
    color: var(--primary-color) !important;
    border-color: #FFD6E7 !important;
}

.fc-theme-standard td,
.fc-theme-standard th {
    border-color: #FADADD !important;
}

.fc-col-header-cell {
    background: linear-gradient(135deg, #FFF0F5 0%, #FFE4E6 100%);
    padding: 12px 0;
    text-transform: uppercase;
    font-size: 0.85rem;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
}

.fc-timegrid-slot {
    background-color: rgba(255, 240, 245, 0.3);
}

.fc-timegrid-slot-label {
    color: var(--text-secondary);
    font-size: 0.75rem;
}

.fc-daygrid-day {
    background-color: rgba(255, 255, 255, 0.6);
}

.fc-day-today {
    background-color: rgba(255, 224, 230, 0.4) !important;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(15, 23, 42, 0.4);
    backdrop-filter: blur(4px);
    align-items: center;
    justify-content: center;
}

.modal-content {
    background: white;
    border-radius: 16px;
    width: 90%;
    max-width: 440px;
    box-shadow: var(--shadow-lg);
    animation: scaleIn 0.2s cubic-bezier(0.16, 1, 0.3, 1);
    position: relative;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.95);
    }

    to {
        opacity: 1;
        transform: scale(1);
    }
}

.modal-header {
    padding: 20px 24px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: #FAFAFA;
}

.modal-header h2 {
    margin: 0;
    font-size: 1.2rem;
    color: var(--text-primary);
    font-weight: 700;
}

.modal-body {
    padding: 24px;
    line-height: 1.6;
    color: var(--text-primary);
}

.modal-footer {
    padding: 16px 24px;
    border-top: 1px solid var(--border-color);
    background: #F8FAFC;
    text-align: right;
    display: flex;
    justify-content: flex-end;
}

/* --- Premium UI Overlay --- */

/* Background Decorations */
.bg-bows {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
    overflow: hidden;
}

.decoration-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
}

.decoration-bow {
    position: absolute;
    opacity: 0.12;
    filter: blur(0.5px);
}

.decoration-bow.top-left {
    top: 20px;
    left: 20px;
    width: 120px;
    height: 96px;
    animation: float 6s ease-in-out infinite;
}

.decoration-bow.bottom-right {
    bottom: 20px;
    right: 20px;
    width: 150px;
    height: 120px;
    animation: float 8s ease-in-out infinite reverse;
}

.decoration-container::before {
    content: '';
    position: absolute;
    top: 15%;
    right: 8%;
    width: 60px;
    height: 48px;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 100 80' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M40 40 C30 40 20 20 20 20 C20 10 30 0 40 10 C45 15 50 25 50 25 C50 25 55 15 60 10 C70 0 80 10 80 20 C80 20 70 40 60 40 C55 40 52 35 50 30 C48 35 45 40 40 40 Z' fill='%23ED0D92'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    opacity: 0.08;
    animation: float 7s ease-in-out infinite 1s;
}

.decoration-container::after {
    content: '';
    position: absolute;
    top: 60%;
    left: 5%;
    width: 50px;
    height: 40px;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 100 80' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M40 40 C30 40 20 20 20 20 C20 10 30 0 40 10 C45 15 50 25 50 25 C50 25 55 15 60 10 C70 0 80 10 80 20 C80 20 70 40 60 40 C55 40 52 35 50 30 C48 35 45 40 40 40 Z' fill='%23ED0D92'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    opacity: 0.08;
    animation: float 5s ease-in-out infinite 0.5s;
}

@keyframes float {

    0%,
    100% {
        transform: translateY(0) rotate(0deg) scale(1);
    }

    25% {
        transform: translateY(-8px) rotate(1deg) scale(1.02);
    }

    50% {
        transform: translateY(-15px) rotate(0deg) scale(1);
    }

    75% {
        transform: translateY(-8px) rotate(-1deg) scale(0.98);
    }
}

/* 2. Glassmorphism Course Cards - Enhanced Readability */
.fc-event {
    border: none !important;
    border-radius: 10px !important;
    padding: 3px !important;
    background: transparent !important;
    box-shadow: none !important;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1) !important;
    overflow: hidden !important;
    cursor: pointer;
    box-sizing: border-box !important;
}

.fc-event-main {
    background: linear-gradient(135deg, var(--student-light, var(--bg-gradient-start)) 0%, var(--card-bg) 100%);
    border-left: 4px solid var(--student-primary, var(--primary-color));
    border-radius: 6px;
    padding: 6px 8px;
    width: 100%;
    height: 100%;
    color: var(--text-primary);
    font-weight: 600;
    font-size: 0.85rem;
    position: relative;
    box-shadow: 0 2px 8px rgba(237, 13, 146, 0.15);
    display: flex;
    flex-direction: column;
    justify-content: center;
    min-height: 36px;
    overflow: hidden;
    box-sizing: border-box;
}

[data-theme="dark"] .fc-event-main {
    background: linear-gradient(135deg, color-mix(in srgb, var(--student-primary, var(--primary-color)), transparent 85%) 0%, var(--card-bg) 100%);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.fc-event-main .fc-event-title {
    color: var(--student-primary, var(--primary-color));
    font-weight: 700;
    font-size: 0.85rem;
    margin-bottom: 2px;
    line-height: 1.2;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.fc-event-main .fc-event-time {
    color: var(--text-secondary);
    font-size: 0.7rem;
    font-weight: 500;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.mobile-event-content {
    display: flex;
    flex-direction: column;
    gap: 2px;
    min-width: 0;
}

.mobile-event-meta {
    display: flex;
    align-items: center;
    gap: 6px;
    min-width: 0;
}

.mobile-event-time-pill {
    display: inline-flex;
    align-items: center;
    padding: 1px 6px;
    border-radius: 999px;
    background: rgba(237, 13, 146, 0.12);
    color: var(--text-secondary);
    font-size: 0.65rem;
    font-weight: 600;
    line-height: 1.2;
    flex-shrink: 0;
    max-width: 100%;
    overflow: hidden;
    text-overflow: ellipsis;
}

.mobile-event-location {
    font-size: 0.65rem;
    color: var(--text-secondary);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    min-width: 0;
}

.mobile-event-price {
    display: inline-flex;
    align-items: center;
    padding: 1px 6px;
    border-radius: 999px;
    background: rgba(46, 204, 113, 0.12);
    color: #1F8A4C;
    font-size: 0.65rem;
    font-weight: 700;
    line-height: 1.2;
    flex-shrink: 0;
}

.month-event-content {
    display: flex;
    flex-direction: column;
    gap: 1px;
    min-width: 0;
}

.month-event-time {
    font-size: 0.7rem;
    color: var(--student-primary, var(--text-secondary));
    line-height: 1.1;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.month-event-title {
    font-size: 0.7rem;
    font-weight: 600;
    line-height: 1.2;
    color: var(--student-primary, var(--primary-color));
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

@media (max-width: 767px) {
    .month-event-title {
        font-size: 0.65rem;
        font-weight: 500;
    }
}

.mobile-list-event {
    display: flex;
    flex-direction: column;
    gap: 4px;
    min-width: 0;
}

.mobile-list-title {
    font-weight: 800;
    font-size: 0.95rem;
    line-height: 1.15;
    color: var(--text-primary);
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
}

/* ========================================
   Desktop Enhanced Course Cards
   当屏幕 >= 1024px 时显示更多课程信息
   ======================================== */

@media (min-width: 1024px) {
    .fc-event-main.desktop-event {
        padding: 4px 7px;
        min-height: 42px;
        justify-content: flex-start;
        gap: 0;
    }

    .fc-event-main.desktop-event .fc-event-title {
        font-size: 0.8rem;
        margin-bottom: 1px;
        line-height: 1.1;
        max-height: 1.1em;
    }

    .fc-event-main.desktop-event .fc-event-time {
        font-size: 0.6rem;
        line-height: 1;
        margin-bottom: 1px;
    }

    /* 额外信息容器 */
    .event-extra-info {
        display: flex;
        align-items: center;
        gap: 4px;
        margin-top: 0;
        flex-wrap: nowrap;
        line-height: 1;
    }

    /* 学生姓名标签 */
    .event-student-name {
        display: inline-flex;
        align-items: center;
        gap: 2px;
        padding: 1px 4px;
        background: rgba(237, 13, 146, 0.08);
        border-radius: 6px;
        font-size: 0.6rem;
        font-weight: 500;
        color: var(--text-primary);
        max-width: 70px;
        overflow: hidden;
        text-overflow: ellipsis;
        white-space: nowrap;
        height: 16px;
        line-height: 14px;
    }

    .event-student-name svg {
        opacity: 0.7;
        flex-shrink: 0;
        width: 10px;
        height: 10px;
    }

    /* 价格标签 */
    .event-price {
        display: inline-flex;
        align-items: center;
        padding: 1px 4px;
        background: rgba(46, 204, 113, 0.1);
        border-radius: 6px;
        font-size: 0.6rem;
        font-weight: 600;
        color: #27AE60;
        flex-shrink: 0;
        height: 16px;
        line-height: 14px;
    }

    /* 桌面端悬停效果 */
    .fc-event-main.desktop-event:hover {
        min-height: 44px;
    }
}

.fc-event:hover {
    transform: translateY(-2px) scale(1.02);
    z-index: 50 !important;
}

/* ========================================
   Current Time Indicator (当前时间指示器)
   ======================================== */

/* 指示器横线 */
.fc-timegrid-now-indicator-line {
    border-color: #ED0D92 !important;
    border-width: 2px !important;
    box-shadow: 0 0 8px rgba(237, 13, 146, 0.6);
}

/* 指示器箭头 */
.fc-timegrid-now-indicator-arrow {
    border-color: #ED0D92 !important;
    border-width: 6px !important;
    margin-top: -6px !important;
}

/* 指示器脉冲动画效果 */
.fc-timegrid-now-indicator-line::after {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 100%;
    height: 6px;
    background: linear-gradient(90deg, transparent, rgba(237, 13, 146, 0.3), transparent);
    animation: pulseLine 2s ease-in-out infinite;
    pointer-events: none;
}

@keyframes pulseLine {

    0%,
    100% {
        opacity: 0.5;
    }

    50% {
        opacity: 1;
    }
}

.fc-event:hover .fc-event-main {
    background: linear-gradient(135deg, #FFE4E6 0%, #FFFFFF 100%);
    box-shadow: 0 6px 20px rgba(237, 13, 146, 0.25);
    border-left-width: 5px;
}

/* Conflict Visualization */
.fc-event.conflict-event .fc-event-main {
    background: linear-gradient(135deg, #FED7D7 0%, #FFFFFF 100%);
    border-left-color: var(--error-color);
    animation: shake 0.5s cubic-bezier(.36, .07, .19, .97) both;
    box-shadow: 0 2px 8px rgba(231, 76, 60, 0.2);
}

@keyframes shake {

    10%,
    90% {
        transform: translate3d(-1px, 0, 0);
    }

    20%,
    80% {
        transform: translate3d(2px, 0, 0);
    }

    30%,
    50%,
    70% {
        transform: translate3d(-4px, 0, 0);
    }

    40%,
    60% {
        transform: translate3d(4px, 0, 0);
    }
}

/* 3. Premium Modal Redesign */
.modal-content {
    border-radius: 20px;
    box-shadow:
        0 20px 25px -5px rgba(0, 0, 0, 0.1),
        0 10px 10px -5px rgba(0, 0, 0, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.8);
    overflow: visible;
    /* Allow buttons to float if needed */
}

.modal-header {
    background: linear-gradient(135deg, #FFF0F5 0%, #FFFFFF 100%);
    padding: 24px 32px;
    border-radius: 20px 20px 0 0;
    border-bottom: 1px solid rgba(237, 13, 146, 0.1);
}

.modal-header h2 {
    font-size: 1.5rem;
    background: linear-gradient(45deg, var(--primary-color), #FF69B4);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    font-weight: 800;
}

.modal-body {
    padding: 32px;
}

.edit-form {
    display: flex;
    flex-direction: column;
    gap: 16px;
    padding: 0;
}

.row-group {
    display: flex;
    gap: 16px;
    width: 100%;
}

.form-group {
    display: flex;
    flex-direction: column;
    flex: 1;
    /* Grow to fill space */
    min-width: 0;
    /* Prevent overflow */
}

.form-group label {
    text-transform: uppercase;
    font-size: 0.75rem;
    letter-spacing: 0.05em;
    color: #94A3B8;
    margin-bottom: 6px;
    font-weight: 600;
}

.form-group input,
.form-group textarea {
    background: #F8FAFC;
    border: 1px solid #E2E8F0;
    border-radius: 12px;
    padding: 12px 16px;
    font-size: 0.95rem;
    /* Slightly smaller for dense Info */
    transition: all 0.2s ease;
    width: 100%;
    box-sizing: border-box;
    /* Crucial for padding */
    font-family: inherit;
    color: var(--text-primary);
}

.form-group input:focus,
.form-group textarea:focus {
    background: #FFF;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(237, 13, 146, 0.1);
    outline: none;
}

/* Student Select Dropdown */
.student-select {
    background: #F8FAFC;
    border: 1px solid #E2E8F0;
    border-radius: 12px;
    padding: 12px 16px;
    font-size: 1rem;
    transition: all 0.2s ease;
    width: 100%;
    cursor: pointer;
    color: var(--text-primary);
}

.student-select:focus {
    background: #FFF;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(237, 13, 146, 0.1);
    transform: translateY(-1px);
    outline: none;
}

.student-select:hover {
    border-color: var(--primary-hover);
}

.no-students-hint {
    background: #FFF5F5;
    border: 1px dashed var(--primary-color);
    border-radius: 12px;
    padding: 16px;
    text-align: center;
}

.no-students-hint p {
    margin: 0 0 8px 0;
    color: var(--text-secondary);
}

.no-students-hint a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}

.no-students-hint a:hover {
    text-decoration: underline;
}

.modal-footer {
    background: #FFF;
    border-top: 1px solid #F1F5F9;
    border-radius: 0 0 20px 20px;
    padding: 20px 32px;
    gap: 16px;
}

.danger-btn {
    color: var(--error-color);
    background: #FEF2F2;
    border: 1px solid #FECACA;
    border-radius: 12px;
}

.danger-btn:hover {
    background: #FEE2E2;
    color: #DC2626;
    border-color: #FCA5A5;
}

/* Enhanced Typing Indicator */
.typing {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 4px 0;
}

.typing-dot {
    width: 8px;
    height: 8px;
    background: var(--primary-color);
    border-radius: 50%;
    animation: typingBounce 1.4s ease-in-out infinite;
    opacity: 0.6;
}

.typing-dot:nth-child(1) {
    animation-delay: 0s;
}

.typing-dot:nth-child(2) {
    animation-delay: 0.2s;
}

.typing-dot:nth-child(3) {
    animation-delay: 0.4s;
}

@keyframes typingBounce {

    0%,
    60%,
    100% {
        transform: translateY(0);
        opacity: 0.6;
    }

    30% {
        transform: translateY(-8px);
        opacity: 1;
    }
}

/* Alternative ellipsis typing animation */
.typing-ellipsis {
    display: inline-block;
    font-weight: bold;
    color: var(--primary-color);
    animation: ellipsisPulse 1.5s ease-in-out infinite;
}

@keyframes ellipsisPulse {
    0% {
        content: '.';
        opacity: 0.3;
    }

    20% {
        content: '..';
        opacity: 0.6;
    }

    40% {
        content: '...';
        opacity: 1;
    }

    60% {
        content: '...';
        opacity: 1;
    }

    80% {
        content: '..';
        opacity: 0.6;
    }

    100% {
        content: '.';
        opacity: 0.3;
    }
}

/* Toast Notification System */
.toast-container {
    position: fixed;
    top: 24px;
    right: 24px;
    z-index: 3000;
    display: flex;
    flex-direction: column;
    gap: 12px;
    pointer-events: none;
}

.toast {
    display: flex;
    align-items: center;
    gap: 12px;
    min-width: 280px;
    max-width: 400px;
    padding: 16px 20px;
    background: white;
    border-radius: 16px;
    box-shadow: 0 10px 40px rgba(237, 13, 146, 0.15);
    pointer-events: auto;
    animation: slideInRight 0.4s cubic-bezier(0.2, 0.8, 0.2, 1);
    position: relative;
    overflow: hidden;
    border: 1px solid rgba(237, 13, 146, 0.1);
}

.toast::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 4px;
    background: var(--primary-color);
}

.toast.toast-success {
    border-color: rgba(46, 204, 113, 0.3);
}

.toast.toast-success::before {
    background: var(--success-color);
}

.toast.toast-error {
    border-color: rgba(231, 76, 60, 0.3);
}

.toast.toast-error::before {
    background: var(--error-color);
}

.toast.toast-warning {
    border-color: rgba(241, 196, 15, 0.3);
}

.toast.toast-warning::before {
    background: var(--warning-color);
}

.toast.toast-removing {
    animation: slideOutRight 0.3s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

@keyframes slideInRight {
    from {
        transform: translateX(120%) scale(0.9);
        opacity: 0;
    }

    to {
        transform: translateX(0) scale(1);
        opacity: 1;
    }
}

@keyframes slideOutRight {
    from {
        transform: translateX(0) scale(1);
        opacity: 1;
    }

    to {
        transform: translateX(120%) scale(0.9);
        opacity: 0;
    }
}

.toast-icon {
    flex-shrink: 0;
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
}

.toast-success .toast-icon {
    background: rgba(46, 204, 113, 0.15);
    color: var(--success-color);
}

.toast-error .toast-icon {
    background: rgba(231, 76, 60, 0.15);
    color: var(--error-color);
}

.toast-warning .toast-icon {
    background: rgba(241, 196, 15, 0.15);
    color: var(--warning-color);
}

.toast-content {
    flex: 1;
}

.toast-title {
    font-weight: 600;
    font-size: 0.95rem;
    color: var(--text-primary);
    margin-bottom: 2px;
}

.toast-message {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.toast-close {
    flex-shrink: 0;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 4px;
    border-radius: 6px;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.toast-close:hover {
    background: rgba(0, 0, 0, 0.05);
    color: var(--text-primary);
}

/* Toast Progress Bar */
.toast-progress {
    position: absolute;
    bottom: 0;
    left: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-color), #FF69B4);
    animation: toastProgress 3s linear forwards;
}

@keyframes toastProgress {
    from {
        width: 100%;
    }

    to {
        width: 0%;
    }
}

/* Form row-group for side-by-side inputs */
.row-group {
    display: flex;
    gap: 16px;
}

.row-group .form-group {
    flex: 1;
}

/* Course Detail View Styles */
.course-detail {
    padding: 8px 0;
}

.detail-header {
    border-left: 4px solid var(--primary-color);
    padding-left: 16px;
    margin-bottom: 24px;
    padding-top: 4px;
}

.detail-title {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.detail-student {
    font-size: 0.95rem;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.detail-student::before {
    content: '';
    width: 8px;
    height: 8px;
    background: currentColor;
    border-radius: 50%;
}

.detail-list {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.detail-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 16px;
    border-radius: 12px;
    background: #F8FAFC;
    transition: all 0.2s ease;
    cursor: pointer;
}

.detail-item:hover {
    background: #F1F5F9;
    transform: translateX(4px);
}

.detail-item:active {
    transform: translateX(2px) scale(0.98);
}

.detail-label {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
}

.detail-label svg {
    opacity: 0.6;
}

.detail-value {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.95rem;
    transition: all 0.2s ease;
}

.detail-value.copyable {
    position: relative;
}

.detail-value.copyable::after {
    content: '点击复制';
    position: absolute;
    right: 0;
    bottom: 100%;
    padding: 4px 8px;
    background: rgba(0, 0, 0, 0.8);
    color: white;
    font-size: 0.75rem;
    border-radius: 4px;
    white-space: nowrap;
    opacity: 0;
    pointer-events: none;
    transform: translateY(-4px);
    transition: all 0.2s ease;
}

.detail-item:hover .detail-value.copyable::after {
    opacity: 1;
    transform: translateY(-2px);
}

.detail-value.linkable {
    color: var(--primary-color);
    text-decoration: underline;
    text-decoration-style: dotted;
    text-underline-offset: 3px;
}

.detail-value.linkable:hover {
    text-decoration-style: solid;
}

.detail-actions {
    display: flex;
    gap: 12px;
    margin-top: 24px;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
}

.detail-actions button {
    flex: 1;
}

/* Course Card Creation Animation */
.fc-event.new-event {
    animation: popIn 0.5s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

@keyframes popIn {
    0% {
        transform: scale(0) rotate(-5deg);
        opacity: 0;
    }

    50% {
        transform: scale(1.1) rotate(2deg);
    }

    70% {
        transform: scale(0.95) rotate(-1deg);
    }

    100% {
        transform: scale(1) rotate(0deg);
        opacity: 1;
    }
}

/* Brand Icon Hover Animation */
.brand-icon {
    width: 28px;
    height: 28px;
    filter: drop-shadow(0 2px 4px rgba(237, 13, 146, 0.2));
    transition: all 0.3s ease;
    cursor: pointer;
}

.brand-icon:hover {
    animation: wiggle 0.5s ease-in-out;
    filter: drop-shadow(0 4px 8px rgba(237, 13, 146, 0.4));
}

@keyframes wiggle {

    0%,
    100% {
        transform: rotate(0deg) scale(1);
    }

    15% {
        transform: rotate(-8deg) scale(1.05);
    }

    30% {
        transform: rotate(6deg) scale(1.02);
    }

    45% {
        transform: rotate(-4deg) scale(1.01);
    }

    60% {
        transform: rotate(2deg) scale(1);
    }

    75% {
        transform: rotate(-1deg) scale(1);
    }
}

/* Calendar View Transition Animation */
.fc-view {
    transition: opacity 0.3s ease, transform 0.3s ease;
}

.fc-view.fc-view-transitioning {
    opacity: 0;
    transform: translateY(10px);
}

.fc-view.fc-view-active {
    opacity: 1;
    transform: translateY(0);
}

/* Calendar button animation */
.fc-button-primary {
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1) !important;
}

.fc-button-primary:hover {
    transform: translateY(-1px) !important;
}

.fc-button-primary:active {
    transform: translateY(0) scale(0.98) !important;
}

/* Enhanced send button animation */
.send-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    flex-shrink: 0;
    position: relative;
    overflow: hidden;
}

.send-btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width 0.4s, height 0.4s;
}

.send-btn:hover::before {
    width: 100%;
    height: 100%;
}

.send-btn:hover {
    background: var(--primary-hover);
    transform: translateY(-2px) scale(1.05);
    box-shadow: 0 6px 20px rgba(237, 13, 146, 0.4);
}

.send-btn:active {
    transform: translateY(0) scale(0.95);
}

.send-btn svg {
    position: relative;
    z-index: 1;
    transition: transform 0.3s;
}

.send-btn:hover svg {
    transform: translateX(2px) translateY(-2px);
}

/* Add course button ripple effect */
.primary-btn {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-hover));
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 20px;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 4px 6px rgba(237, 13, 146, 0.2);
    position: relative;
    overflow: hidden;
}

.primary-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    transition: left 0.5s;
}

.primary-btn:hover::before {
    left: 100%;
}

.primary-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(237, 13, 146, 0.35);
}

.primary-btn:active {
    transform: translateY(0) scale(0.98);
}

.primary-btn svg {
    transition: transform 0.3s;
}

.primary-btn:hover svg {
    transform: rotate(90deg);
}

/* Icon button enhanced hover */
.icon-btn {
    background: transparent;
    border: 1px solid transparent;
    cursor: pointer;
    padding: 8px;
    border-radius: 8px;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.icon-btn:hover {
    background-color: #FFF0F5;
    color: var(--primary-color);
    transform: scale(1.05);
}

.icon-btn:active {
    transform: scale(0.95);
}

.icon-btn svg {
    transition: transform 0.3s;
}

.icon-btn:hover svg {
    transform: scale(1.1);
}

/* Page title bow icon animation */
.bow-icon-small {
    width: 24px;
    height: 24px;
    transition: all 0.3s ease;
}

.bow-icon-small:hover {
    transform: scale(1.15) rotate(5deg);
    filter: drop-shadow(0 2px 4px rgba(237, 13, 146, 0.3));
}

/* Smooth scroll behavior */
.messages {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 16px;
    scroll-behavior: smooth;
}

/* Scrollbar Polish */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: #CBD5E1;
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: #94A3B8;
}

/* Responsive Logic Refined */

/* Desktop (>= 1024px) */
@media (min-width: 1024px) {
    .sidebar {
        /* On desktop, sidebar is always visible by default */
        transform: translateX(0);
        left: 0;
        z-index: 10;
        /* Sidebar is part of flow or absolute?
           Let's make it fixed/absolute and push content.
        */
        position: fixed;
        height: 100vh;
    }

    .main-content {
        margin-left: var(--sidebar-width);
        /* Push content */
    }

    .sidebar.closed {
        transform: translateX(-100%);
    }

    .sidebar.closed~.main-content {
        margin-left: 0;
        /* Content expands filling space */
    }

    .sidebar-overlay {
        display: none !important;
    }

    .close-sidebar-btn {
        display: none;
    }
}

/* Mobile (< 1024px) */
@media (max-width: 1023px) {
    .sidebar {
        position: fixed;
        left: 0;
        top: 0;
        bottom: 0;
        transform: translateX(-100%);
        /* Hidden by default */
        z-index: 2000;
        width: 85%;
        /* Slightly narrower on mobile */
        max-width: 340px;
    }

    .main-content {
        margin-left: 0 !important;
        /* Always full width */
    }

    .sidebar.mobile-open {
        transform: translateX(0);
    }

    .btn-text {
        display: none;
        /* Hide text on small screens if needed, or keep it */
    }

    .top-actions .primary-btn {
        padding: 8px;
        /* Compact button */
    }

    .top-actions .primary-btn .btn-text {
        display: none;
    }
}

/* Mobile Specific Styles (< 768px) */
@media (max-width: 767px) {
    body {
        font-size: 14px;
    }

    .calendar-wrapper {
        padding: 12px;
    }

    .calendar-header {
        padding: 10px 12px;
        border-radius: 14px 14px 0 0;
        gap: 10px;
    }

    .calendar-title {
        font-size: 1rem;
        line-height: 1.2;
    }

    .nav-btn {
        width: 34px;
        height: 34px;
        border-radius: 10px;
    }

    .nav-btn svg {
        width: 18px;
        height: 18px;
    }

    .calendar-views {
        padding: 3px;
        border-radius: 10px;
        gap: 4px;
    }

    .view-btn {
        padding: 6px 10px;
        border-radius: 10px;
        font-size: 0.68rem;
        gap: 2px;
    }

    /* FullCalendar Mobile Optimizations */
    .fc-toolbar {
        flex-direction: column !important;
        gap: 8px !important;
    }

    .fc-toolbar-chunk {
        display: flex;
        justify-content: center;
        width: 100% !important;
    }

    .fc-toolbar-title {
        font-size: 1rem !important;
    }

    .fc-button-primary {
        padding: 6px 12px !important;
        font-size: 0.85rem !important;
    }

    /* Compact time grid on mobile */
    .fc-timegrid-slot {
        height: 40px !important;
    }

    .fc-timegrid-slot-label {
        font-size: 0.7rem !important;
        width: 35px !important;
    }

    .fc-col-header-cell {
        padding: 8px 4px !important;
        font-size: 0.75rem !important;
    }

    /* Event cards mobile optimization */
    .fc-event-main {
        font-size: 0.78rem !important;
        padding: 4px 5px !important;
        min-height: 34px;
    }

    .fc-timegrid-event .fc-event-main {
        justify-content: flex-start;
        gap: 2px;
    }

    .fc-timegrid-event .fc-event-main .fc-event-title {
        white-space: normal;
        overflow: hidden;
        text-overflow: ellipsis;
        display: -webkit-box;
        -webkit-line-clamp: 2;
        -webkit-box-orient: vertical;
        line-height: 1.15;
        margin-bottom: 0;
    }

    .fc-timegrid-event .fc-event-main .fc-event-time {
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
    }

    /* Hide less important elements on mobile */
    .fc-scrollgrid-shrink {
        width: 40px !important;
    }

    .fc-list {
        background: transparent;
    }

    .fc .fc-list-table {
        border: none;
        border-radius: 14px;
        overflow: hidden;
        background: rgba(255, 255, 255, 0.7);
        box-shadow: 0 6px 18px rgba(237, 13, 146, 0.08);
    }

    .fc .fc-list-day-cushion {
        background: linear-gradient(135deg, rgba(255, 240, 245, 0.95) 0%, rgba(255, 255, 255, 0.95) 100%);
        color: var(--text-primary);
        font-weight: 800;
        padding: 10px 12px;
        border-bottom: 1px solid rgba(237, 13, 146, 0.08);
    }

    .fc .fc-list-event td {
        border-color: rgba(237, 13, 146, 0.08);
        padding: 10px 12px;
        background: transparent;
    }

    .fc .fc-list-event:hover td {
        background: rgba(237, 13, 146, 0.04);
    }

    .fc .fc-list-event-time {
        display: none;
    }

    .fc .fc-list-event-title a {
        color: inherit;
        text-decoration: none;
        padding: 0;
        display: block;
    }

    .fc .fc-list-event-title a:focus {
        outline: none;
    }

    /* Modal mobile optimization */
    .modal {
        align-items: flex-end;
        justify-content: center;
        padding: 0;
    }

    .modal-content {
        width: 100%;
        max-width: none;
        margin: 0;
        border-radius: 18px 18px 0 0;
        max-height: 88vh;
        overflow: auto;
        animation: slideUp 0.22s cubic-bezier(0.16, 1, 0.3, 1);
    }

    @keyframes slideUp {
        from {
            opacity: 0;
            transform: translateY(16px);
        }

        to {
            opacity: 1;
            transform: translateY(0);
        }
    }

    .modal-header {
        padding: 16px 20px;
    }

    .modal-header h2 {
        font-size: 1.2rem;
    }

    .modal-body {
        padding: 20px;
    }

    .modal-footer {
        padding: 16px 20px;
        flex-wrap: wrap;
        gap: 8px;
    }

    .modal-footer button {
        flex: 1;
        min-width: 80px;
        font-size: 0.9rem;
    }

    /* Form adjustments for mobile */
    .edit-form {
        gap: 16px;
    }

    .form-group {
        margin-bottom: 12px;
    }

    .form-group label {
        font-size: 0.7rem;
    }

    .form-group input {
        padding: 10px 12px;
        font-size: 0.95rem;
    }

    .row-group {
        flex-direction: column;
        gap: 12px;
    }

    /* Chat mobile optimization */
    .messages {
        padding: 12px;
    }

    .message {
        max-width: 95%;
        font-size: 0.9rem;
    }

    .input-area {
        padding: 12px;
    }

    .input-area textarea {
        font-size: 0.9rem;
    }

    /* Top bar mobile optimization */
    .top-bar {
        padding-left: calc(12px + env(safe-area-inset-left));
        padding-right: calc(12px + env(safe-area-inset-right));
        height: calc(52px + env(safe-area-inset-top));
        padding-top: env(safe-area-inset-top);
    }

    .page-title h1 {
        font-size: 1.1rem;
    }

    .tab-navigation {
        padding: 3px;
        border-radius: 10px;
        gap: 6px;
    }

    .tab-btn {
        padding: 7px 10px;
        font-size: 0.85rem;
        gap: 6px;
    }

    .tab-btn svg {
        width: 16px;
        height: 16px;
    }

    .students-wrapper {
        padding: 12px;
    }

    .students-list {
        grid-template-columns: 1fr;
        gap: 12px;
    }

    .student-card {
        padding: 16px;
    }

    /* Button spacing adjustments */
    .primary-btn,
    .secondary-btn,
    .danger-btn {
        padding: 8px 16px;
        font-size: 0.9rem;
    }
}

/* Extra Small Mobile (< 480px) */
@media (max-width: 479px) {
    .fc-toolbar-chunk {
        flex-wrap: wrap;
    }

    .fc-button-group {
        display: flex;
        flex-wrap: wrap;
        gap: 4px;
    }

    .fc-timegrid-slot {
        height: 36px !important;
    }

    .fc-event-main {
        font-size: 0.72rem !important;
        padding: 3px 4px !important;
    }

    .mobile-event-location {
        display: none;
    }

    .calendar-wrapper {
        padding: 8px;
    }

    .view-btn span {
        display: none;
    }

    .tab-btn span {
        display: none;
    }
}

/* --- Tool Execution Hat (Hello Kitty Style) --- */
.tool-hat {
    background: linear-gradient(90deg, #ED0D92 0%, #FF69B4 100%);
    color: white;
    padding: 8px 16px;
    /* Match the border-radius of .ai-message .message-content but only top */
    border-radius: 2px 16px 0 0; 
    /* Counteract the padding of .message-content (14px 18px) */
    margin: -14px -18px 14px -18px;
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 0.85rem;
    font-weight: 600;
    box-shadow: 0 4px 6px rgba(237, 13, 146, 0.2);
    animation: hatSlideDown 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
    position: relative;
    overflow: hidden;
    z-index: 10;
    border-bottom: 1px solid rgba(255, 255, 255, 0.3);
}

.tool-hat.hiding {
    animation: hatSlideUp 0.3s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

@keyframes hatSlideDown {
    from {
        transform: translateY(-100%);
        opacity: 0;
        max-height: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
        max-height: 50px;
    }
}

@keyframes hatSlideUp {
    from {
        transform: translateY(0);
        opacity: 1;
        max-height: 50px;
        margin-bottom: 14px;
    }
    to {
        transform: translateY(-20px);
        opacity: 0;
        max-height: 0;
        margin-bottom: 0;
        padding-top: 0;
        padding-bottom: 0;
    }
}

/* Moving stripes background for the hat */
.tool-hat::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: repeating-linear-gradient(
        45deg,
        rgba(255, 255, 255, 0.1),
        rgba(255, 255, 255, 0.1) 10px,
        transparent 10px,
        transparent 20px
    );
    animation: hatStripes 20s linear infinite;
    pointer-events: none;
}

@keyframes hatStripes {
    from { background-position: 0 0; }
    to { background-position: 500px 0; }
}

.tool-hat-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 20px;
    height: 20px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    animation: hatIconSpin 2s linear infinite;
}

@keyframes hatIconSpin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.tool-hat-text {
    flex: 1;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
}

.tool-hat.locked {
    cursor: pointer;
    user-select: none;
    display: block;
}

.tool-hat.locked::after {
    right: 44px;
}

.tool-hat::after {
    pointer-events: none;
}

.tool-hat.locked .tool-hat-icon {
    animation: none;
}

.tool-hat-row {
    display: flex;
    align-items: center;
    gap: 10px;
    position: relative;
    z-index: 1;
}

.tool-hat-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 24px;
    height: 24px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.18);
    transition: transform 0.2s ease, background 0.2s ease;
}

.tool-hat:hover .tool-hat-toggle {
    background: rgba(255, 255, 255, 0.26);
}

.tool-hat.expanded .tool-hat-toggle {
    transform: rotate(180deg);
}

.tool-hat-details {
    position: relative;
    z-index: 1;
    margin-top: 10px;
    background: rgba(255, 255, 255, 0.14);
    border: 1px solid rgba(255, 255, 255, 0.22);
    border-radius: 14px;
    padding: 10px 10px;
    overflow: hidden;
    max-height: 420px;
    opacity: 1;
    transition: max-height 0.25s ease, opacity 0.2s ease, margin-top 0.2s ease;
}

.tool-hat.collapsed .tool-hat-details {
    max-height: 0;
    opacity: 0;
    margin-top: 0;
    padding-top: 0;
    padding-bottom: 0;
    border-width: 0;
}

.tool-hat-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px 10px;
    border-radius: 12px;
    background: rgba(255, 255, 255, 0.08);
}

.tool-hat-item + .tool-hat-item {
    margin-top: 8px;
}

.tool-hat-item-index {
    width: 22px;
    height: 22px;
    border-radius: 999px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: 800;
    background: rgba(255, 255, 255, 0.22);
}

.tool-hat-item-icon {
    width: 22px;
    height: 22px;
    border-radius: 999px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.18);
}

.tool-hat-item-name {
    flex: 1;
    font-size: 0.82rem;
    font-weight: 650;
    line-height: 1.2;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

@media (max-width: 767px) {
    .tool-hat {
        padding: 8px 14px;
        margin: -14px -14px 12px -14px;
    }

    .tool-hat.locked::after {
        right: 40px;
    }

    .tool-hat-details {
        max-height: 320px;
    }
}

@media (max-width: 479px) {
    .tool-hat {
        padding: 8px 12px;
        margin: -14px -12px 12px -12px;
    }

    .tool-hat-item-name {
        font-size: 0.78rem;
    }
}

/* Hello Kitty Bow Decoration on the Hat */
.tool-hat::after {
    content: '';
    position: absolute;
    right: 10px;
    top: 50%;
    transform: translateY(-50%);
    width: 24px;
    height: 20px;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 100 80' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M40 40 C30 40 20 20 20 20 C20 10 30 0 40 10 C45 15 50 25 50 25 C50 25 55 15 60 10 C70 0 80 10 80 20 C80 20 70 40 60 40 C55 40 52 35 50 30 C48 35 45 40 40 40 Z' fill='white' opacity='0.8'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: center;
    background-size: contain;
    filter: drop-shadow(0 1px 2px rgba(0,0,0,0.1));
    animation: bowWiggle 3s ease-in-out infinite;
}

@keyframes bowWiggle {
    0%, 100% { transform: translateY(-50%) rotate(0deg); }
    50% { transform: translateY(-50%) rotate(10deg); }
}