/* LearnCentre - AI Учебный Центр | Premium Modern Design */

:root {
    --bg-primary: #f0f4ff;
    --bg-secondary: #ffffff;
    --bg-card: #ffffff;
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --accent: #6366f1;
    --accent-hover: #4f46e5;
    --accent-glow: rgba(99, 102, 241, 0.4);
    --ai-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #a855f7 100%);
    --ai-subtle: rgba(99, 102, 241, 0.08);
    --border: #e2e8f0;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --text-accent: #6366f1;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.07);
    --shadow-lg: 0 25px 50px -12px rgba(99, 102, 241, 0.15);
    --glass: rgba(255, 255, 255, 0.7);
    --glass-border: rgba(255, 255, 255, 0.5);
}

[data-theme="dark"] {
    --bg-primary: #0c0f1a;
    --bg-secondary: #141824;
    --bg-card: #1a1f2e;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --border: #2d3548;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    --ai-subtle: rgba(99, 102, 241, 0.15);
    --glass: rgba(26, 31, 46, 0.95);
    --glass-border: rgba(99, 102, 241, 0.15);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background 0.4s ease, color 0.3s ease;
    overflow-x: hidden;
}

/* Theme-aware text utilities */
.text-secondary {
    color: var(--text-secondary) !important;
}

.text-accent {
    color: var(--accent) !important;
}

/* AI Particles + Floating Orbs */
.ai-particles {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
    overflow: hidden;
}

.ai-particles::before {
    content: '';
    position: absolute;
    inset: 0;
    background: 
        radial-gradient(ellipse 100% 60% at 20% 0%, rgba(99, 102, 241, 0.12) 0%, transparent 50%),
        radial-gradient(ellipse 80% 50% at 80% 100%, rgba(168, 85, 247, 0.08) 0%, transparent 50%),
        radial-gradient(ellipse 60% 40% at 50% 50%, rgba(99, 102, 241, 0.04) 0%, transparent 70%);
    opacity: 0;
    animation: particlesFadeIn 1.5s ease forwards;
}

.ai-particles::after {
    content: '';
    position: absolute;
    inset: 0;
    background-image: 
        linear-gradient(var(--border) 1px, transparent 1px),
        linear-gradient(90deg, var(--border) 1px, transparent 1px);
    background-size: 80px 80px;
    opacity: 0.08;
    mask-image: radial-gradient(ellipse at center, black 15%, transparent 65%);
    animation: gridPulse 8s ease-in-out infinite;
}

@keyframes particlesFadeIn {
    to { opacity: 1; }
}

@keyframes gridPulse {
    0%, 100% { opacity: 0.06; }
    50% { opacity: 0.12; }
}

/* Floating orbs */
.orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(60px);
    opacity: 0.5;
    animation: orbFloat 15s ease-in-out infinite;
}

.orb-1 { width: 300px; height: 300px; background: rgba(99, 102, 241, 0.2); top: -100px; right: -100px; animation-delay: 0s; }
.orb-2 { width: 200px; height: 200px; background: rgba(168, 85, 247, 0.15); bottom: 20%; left: -50px; animation-delay: -5s; }
.orb-3 { width: 150px; height: 150px; background: rgba(99, 102, 241, 0.1); top: 50%; right: 10%; animation-delay: -10s; }

@keyframes orbFloat {
    0%, 100% { transform: translate(0, 0) scale(1); }
    33% { transform: translate(30px, -20px) scale(1.05); }
    66% { transform: translate(-20px, 20px) scale(0.95); }
}

/* Sidebar */
.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    width: 280px;
    height: 100vh;
    background: var(--glass);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-right: 1px solid var(--glass-border);
    display: flex;
    flex-direction: column;
    z-index: 1000;
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), box-shadow 0.3s ease;
}

.sidebar-header {
    padding: 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--border);
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: inherit;
    text-decoration: none;
}

.logo:hover {
    color: inherit;
}

.logo-icon {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--ai-gradient);
    color: white;
    font-size: 1.3rem;
    border-radius: 12px;
    animation: logoPulse 3s ease-in-out infinite;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
}

@keyframes logoPulse {
    0%, 100% { box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4); }
    50% { box-shadow: 0 0 30px rgba(99, 102, 241, 0.6); }
}

.logo-text {
    font-weight: 700;
    font-size: 1.25rem;
    background: var(--ai-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.sidebar-toggle {
    background: none;
    border: none;
    font-size: 1.25rem;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 0.25rem;
}

.sidebar-toggle-btn:hover {
    color: var(--accent);
}

.sidebar-nav {
    flex: 1;
    padding: 1rem 0.75rem;
    overflow-y: auto;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.8rem 1rem;
    margin-bottom: 0.35rem;
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: 14px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
}

.nav-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 4px;
    height: 0;
    background: var(--ai-gradient);
    border-radius: 0 4px 4px 0;
    transition: height 0.3s ease;
}

.nav-item:hover {
    background: var(--ai-subtle);
    color: var(--accent);
    transform: translateX(6px);
}

.nav-item.active {
    background: var(--ai-subtle);
    color: var(--accent);
    font-weight: 600;
}

.nav-item.active::before {
    height: 60%;
}

.nav-item i {
    font-size: 1.2rem;
    flex-shrink: 0;
    transition: transform 0.2s;
}

.nav-item:hover i {
    transform: scale(1.1);
}

.nav-item-ai {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.08) 0%, rgba(168, 85, 247, 0.08) 100%);
    border: 1px solid rgba(99, 102, 241, 0.2);
}

.nav-item-ai:hover, .nav-item-ai.active {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.18) 0%, rgba(168, 85, 247, 0.18) 100%);
}

.nav-item-out {
    margin-top: 0.5rem;
    color: var(--text-secondary);
}

.nav-item-out:hover {
    color: var(--accent);
}

.ai-badge {
    margin-left: auto;
    font-size: 0.6rem;
    font-weight: 700;
    padding: 0.2rem 0.5rem;
    background: var(--ai-gradient);
    color: white;
    border-radius: 8px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.nav-pulse {
    position: absolute;
    right: 1rem;
    width: 8px;
    height: 8px;
    background: var(--accent);
    border-radius: 50%;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); box-shadow: 0 0 0 0 rgba(99, 102, 241, 0.4); }
    50% { opacity: 0.8; transform: scale(1.2); box-shadow: 0 0 0 6px rgba(99, 102, 241, 0); }
}

.sidebar-footer {
    padding: 1.25rem 1rem;
    border-top: 1px solid var(--border);
    background: rgba(99, 102, 241, 0.03);
}

/* Sidebar theme toggle */
.theme-toggle-sidebar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    padding: 0.5rem 0;
}

.theme-toggle-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.theme-toggle {
    width: 56px;
    height: 28px;
    padding: 0;
    background: var(--border);
    border: none;
    border-radius: 14px;
    cursor: pointer;
    position: relative;
    transition: all 0.3s ease;
}

.theme-toggle:hover {
    background: var(--ai-subtle);
}

.theme-toggle-inner {
    position: absolute;
    top: 50%;
    left: 4px;
    transform: translateY(-50%);
    width: 22px;
    height: 22px;
    background: var(--ai-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 0.75rem;
    transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

.theme-toggle .theme-icon-dark { display: none; }
.theme-toggle .theme-icon-light { display: block; }

[data-theme="dark"] .theme-toggle .theme-icon-dark { display: block; }
[data-theme="dark"] .theme-toggle .theme-icon-light { display: none; }

[data-theme="dark"] .theme-toggle .theme-toggle-inner {
    left: 30px;
}

/* Topbar theme switcher - always visible */
.theme-switcher-topbar {
    display: flex;
    align-items: center;
}

.theme-switch-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.4rem 0.75rem;
    background: var(--ai-subtle);
    border: 1px solid var(--border);
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.25s ease;
}

.theme-switch-btn:hover {
    background: rgba(99, 102, 241, 0.15);
    border-color: rgba(99, 102, 241, 0.3);
    transform: scale(1.02);
}

.theme-switch-btn:active {
    transform: scale(0.98);
}

.theme-switch-track {
    display: flex;
    align-items: center;
    width: 44px;
    height: 24px;
    background: var(--border);
    border-radius: 12px;
    padding: 2px;
    transition: background 0.3s;
}

.theme-switch-thumb {
    width: 20px;
    height: 20px;
    background: var(--ai-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 0.7rem;
    transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Light theme: sun on left */
.theme-switch-thumb .theme-icon-sun { display: block; }
.theme-switch-thumb .theme-icon-moon { display: none; }

/* Dark theme: moon on right */
[data-theme="dark"] .theme-switch-thumb {
    transform: translateX(20px);
}
[data-theme="dark"] .theme-switch-thumb .theme-icon-sun { display: none; }
[data-theme="dark"] .theme-switch-thumb .theme-icon-moon { display: block; }

.theme-switch-label {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-secondary);
    min-width: 55px;
}

[data-theme="dark"] .theme-switch-label {
    color: var(--accent);
}

.theme-icon-light { display: none; }
.theme-icon-dark { display: block; }

[data-theme="dark"] .theme-icon-light { display: block; }
[data-theme="dark"] .theme-icon-dark { display: none; }

/* Main content */
.main-content {
    margin-left: 280px;
    min-height: 100vh;
    position: relative;
    z-index: 1;
}

.topbar {
    position: sticky;
    top: 0;
    height: 72px;
    background: var(--glass);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    padding: 0 2rem;
    z-index: 100;
    transition: background 0.4s ease, border-color 0.3s ease;
}

[data-theme="dark"] .topbar {
    background: rgba(26, 31, 46, 0.9);
}

[data-theme="dark"] .form-control {
    background: var(--bg-card);
    color: var(--text-primary);
    border-color: var(--border);
}

[data-theme="dark"] .form-control:focus {
    background: var(--bg-card);
    color: var(--text-primary);
    border-color: var(--accent);
}

.topbar-title {
    font-weight: 700;
    font-size: 1.35rem;
    letter-spacing: -0.02em;
}

.topbar-actions {
    margin-left: auto;
}

/* Уведомления: иконка и выпадающий список */
.notifications-wrap {
    display: flex;
    align-items: center;
}
.notifications-btn {
    position: relative;
    color: var(--text-secondary) !important;
    text-decoration: none !important;
}
.notifications-btn:hover {
    color: var(--accent) !important;
}
.notifications-badge {
    position: absolute;
    top: -4px;
    right: -4px;
    min-width: 18px;
    height: 18px;
    padding: 0 5px;
    font-size: 0.7rem;
    font-weight: 700;
    line-height: 18px;
    text-align: center;
    background: var(--danger);
    color: #fff;
    border-radius: 50px;
}
.notifications-dropdown {
    display: none;
    position: absolute;
    top: 100%;
    right: 0;
    margin-top: 8px;
    min-width: 320px;
    max-width: 380px;
    max-height: 400px;
    overflow: hidden;
    border-radius: 14px;
    border: 1px solid var(--border);
    background: var(--bg-card);
    z-index: 1050;
}
.notifications-dropdown.show {
    display: block;
}
.notifications-list {
    max-height: 320px;
    overflow-y: auto;
}
.notification-item {
    display: block;
    padding: 12px 16px;
    border-bottom: 1px solid var(--border);
    color: inherit;
    text-decoration: none;
    transition: background 0.2s;
}
.notification-item:hover {
    background: var(--ai-subtle);
}
.notification-item.unread {
    background: rgba(99, 102, 241, 0.06);
}
.notification-item .notification-title {
    font-weight: 600;
    font-size: 0.9rem;
}
.notification-item .notification-meta {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: 4px;
}

/* Тёмная тема: уведомления и новости — читаемый текст */
[data-theme="dark"] .notifications-dropdown,
[data-theme="dark"] .notifications-header,
[data-theme="dark"] .notifications-list {
    background: var(--bg-card);
    color: var(--text-primary);
}
[data-theme="dark"] .notifications-header {
    border-bottom-color: var(--border);
}
[data-theme="dark"] .notifications-header strong,
[data-theme="dark"] .notification-item .notification-title {
    color: var(--text-primary);
}
[data-theme="dark"] .notification-item .notification-meta,
[data-theme="dark"] .notifications-header .btn-link {
    color: var(--text-secondary) !important;
}
[data-theme="dark"] .notification-item:hover {
    background: var(--ai-subtle);
}
[data-theme="dark"] .notification-item.unread {
    background: rgba(99, 102, 241, 0.12);
}
[data-theme="dark"] #notificationsEmpty,
[data-theme="dark"] .notifications-list .text-center.text-secondary {
    color: var(--text-secondary) !important;
}

/* Тёмная тема: новости и карточки — читаемый текст */
[data-theme="dark"] .student-page .card-ai,
[data-theme="dark"] .student-page .card-ai h4,
[data-theme="dark"] .student-page .card-ai .fw-bold {
    color: var(--text-primary);
}
[data-theme="dark"] .student-page a.text-body {
    color: var(--text-primary);
}
[data-theme="dark"] .student-page a.text-body:hover .card-ai {
    border-color: var(--accent);
}
[data-theme="dark"] .student-page .card-ai .text-secondary {
    color: var(--text-secondary) !important;
}

/* Оформление уведомлений: карточки, отступы */
.notifications-dropdown {
    box-shadow: 0 12px 40px rgba(0,0,0,0.12);
}
[data-theme="dark"] .notifications-dropdown {
    box-shadow: 0 12px 40px rgba(0,0,0,0.5);
}
.notifications-header {
    background: var(--ai-subtle);
    padding: 12px 16px;
}
.notification-item {
    padding: 14px 16px;
    border-bottom: 1px solid var(--border);
    transition: background 0.15s;
}
.notification-item:last-child {
    border-bottom: none;
}
.notification-item .notification-title {
    display: block;
    margin-bottom: 2px;
}

.user-avatar {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    overflow: hidden;
    border: 2px solid transparent;
    background: var(--ai-gradient);
    cursor: pointer;
    transition: all 0.3s ease;
}

.user-avatar:hover {
    transform: scale(1.08);
    box-shadow: 0 0 20px var(--accent-glow);
}

.avatar-initials {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    height: 100%;
    min-width: 100%;
    min-height: 100%;
    background: var(--ai-gradient);
    color: white;
    font-weight: 700;
    font-size: 0.95rem;
    text-decoration: none;
}

.page-content {
    padding: 2rem;
    animation: contentFadeIn 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes contentFadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Cards - Glassmorphism */
.card-ai {
    background: var(--glass);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--border);
    border-radius: 20px;
    padding: 1.75rem;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.card-ai:hover {
    border-color: rgba(99, 102, 241, 0.4);
    box-shadow: 0 12px 32px -12px var(--accent-glow);
    transform: translateY(-3px);
}

/* Form inputs */
.form-control:focus,
.form-control:hover {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--ai-subtle);
}

.form-control {
    transition: border-color 0.2s, box-shadow 0.2s;
}

.card-glow {
    position: relative;
    overflow: hidden;
}

.card-glow::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--ai-gradient);
    opacity: 0;
    transition: opacity 0.3s;
}

.card-ai:hover.card-glow::before {
    opacity: 1;
}

/* Видео о курсе — контейнер 16:9, контент на всю область */
#trailerVideoContainer {
    position: relative;
}
#trailerVideoContainer > * {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}
#trailerVideoContainer iframe {
    display: block;
}

.card-header-custom {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 1.25rem;
}

.card-title-custom {
    font-size: 1.15rem;
    font-weight: 600;
}

/* Stats */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.25rem;
}

.stat-card {
    background: var(--glass);
    backdrop-filter: blur(12px);
    border: 1px solid var(--border);
    border-radius: 20px;
    padding: 1.5rem;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
}

.stat-card::after {
    content: '';
    position: absolute;
    bottom: 0;
    right: 0;
    width: 80px;
    height: 80px;
    background: var(--ai-gradient);
    border-radius: 50%;
    opacity: 0.08;
    transform: translate(30%, 30%);
}

.stat-card:hover,
.stat-card-hover:hover {
    transform: translateY(-5px);
    border-color: rgba(99, 102, 241, 0.35);
    box-shadow: var(--shadow-lg);
}

.stat-card .stat-value {
    transition: transform 0.3s ease;
}

.stat-card:hover .stat-value {
    transform: scale(1.05);
}

.stat-value {
    font-size: 2rem;
    font-weight: 800;
    background: var(--ai-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.03em;
    display: inline-block;
}

.stat-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-top: 0.35rem;
}

/* Progress */
.progress-ai {
    height: 10px;
    background: var(--border);
    border-radius: 999px;
    overflow: hidden;
}

.progress-ai .progress-bar {
    background: var(--ai-gradient);
    border-radius: 999px;
    transition: width 1.2s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Badges */
.badge-ai {
    background: var(--ai-subtle);
    color: var(--accent);
    padding: 0.4rem 0.85rem;
    border-radius: 10px;
    font-size: 0.75rem;
    font-weight: 600;
}

/* Nav pills */
.nav-pills .nav-link {
    border-radius: 12px;
    color: var(--text-secondary);
    padding: 0.6rem 1.25rem;
}

.nav-pills .nav-link.active {
    background: var(--ai-gradient);
    color: white;
}

/* Buttons */
.btn-ai {
    background: var(--ai-gradient);
    border: none;
    color: white;
    padding: 0.65rem 1.5rem;
    border-radius: 14px;
    font-weight: 600;
    transition: all 0.3s ease;
}

.btn-ai:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px var(--accent-glow);
    color: white;
}

/* Section titles */
.section-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.section-title i {
    color: var(--accent);
}

/* Page hero */
.student-page .page-hero {
    margin-bottom: 2rem;
}

.page-hero h1 {
    font-size: 1.75rem;
    font-weight: 700;
    letter-spacing: -0.025em;
    margin-bottom: 0.5rem;
}

.page-hero .lead {
    color: var(--text-secondary);
    font-size: 0.9375rem;
}

/* Lesson/Grade items */
.lesson-card {
    background: var(--ai-subtle);
    border: 1px solid rgba(99, 102, 241, 0.15);
    transition: all 0.3s ease;
}

.lesson-card:hover {
    transform: translateX(6px);
    border-color: rgba(99, 102, 241, 0.3);
}

.lesson-item, .grade-item {
    transition: all 0.3s ease;
}

.grade-item:hover {
    transform: translateX(4px);
}

/* AI Chat */
.chat-header .rounded-circle {
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}

.chat-messages .message div[style*="background"] {
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

/* Animations */
.animate-on-scroll {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.6s cubic-bezier(0.4, 0, 0.2, 1), transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.animate-on-scroll.animate-in {
    opacity: 1;
    transform: translateY(0);
}

.stagger-1 { transition-delay: 0.08s; }
.stagger-2 { transition-delay: 0.16s; }
.stagger-3 { transition-delay: 0.24s; }
.stagger-4 { transition-delay: 0.32s; }
.stagger-5 { transition-delay: 0.4s; }

.anim-fade-up {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.5s ease, transform 0.5s ease;
}

.anim-fade-up.animate-in {
    opacity: 1;
    transform: translateY(0);
}

.anim-delay-1 { transition-delay: 0.1s; }
.anim-delay-2 { transition-delay: 0.2s; }
.anim-delay-3 { transition-delay: 0.3s; }

/* Theme toast */
.theme-toast {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    padding: 0.75rem 1.25rem;
    background: var(--glass);
    backdrop-filter: blur(12px);
    border: 1px solid var(--border);
    border-radius: 12px;
    font-size: 0.9rem;
    font-weight: 500;
    z-index: 2000;
    animation: toastIn 0.4s ease, toastOut 0.3s ease 2s forwards;
}

@keyframes toastIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes toastOut {
    to { opacity: 0; transform: translateY(-10px); }
}

/* Focus visible */
.theme-toggle:focus-visible,
.theme-switch-btn:focus-visible,
.btn-ai:focus-visible,
.nav-item:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

/* Скрытие бокового меню (десктоп): кнопка в topbar */
@media (min-width: 992px) {
    body.sidebar-collapsed .sidebar {
        transform: translateX(-100%);
    }
    body.sidebar-collapsed .main-content {
        margin-left: 0;
    }
    body.sidebar-collapsed .sidebar-toggle-btn .sidebar-icon-hide {
        display: none !important;
    }
    body.sidebar-collapsed .sidebar-toggle-btn .sidebar-icon-show {
        display: inline-block !important;
    }
}

@media (max-width: 991px) {
    .sidebar {
        transform: translateX(-100%);
        background: var(--bg-secondary);
    }
    
    .sidebar.open {
        transform: translateX(0);
        box-shadow: 10px 0 50px rgba(0,0,0,0.2);
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .topbar {
        height: 64px;
    }
    
    .sidebar-toggle-btn .sidebar-icon-hide {
        display: none !important;
    }
    .sidebar-toggle-btn .sidebar-icon-show {
        display: inline-block !important;
    }
}

@media (max-width: 576px) {
    .theme-switch-label {
        display: none;
    }
    
    .theme-switch-btn {
        padding: 0.5rem;
    }
}

/* Стилизованная кнопка выбора файла */
.file-input-wrap {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
}
.file-input-wrap input[type="file"] {
    position: absolute;
    width: 0.1px;
    height: 0.1px;
    opacity: 0;
    overflow: hidden;
    z-index: -1;
}
.btn-choose-file {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 18px;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--accent);
    background: var(--ai-subtle);
    border: 2px solid var(--accent);
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.2s ease;
}
.btn-choose-file:hover {
    background: var(--accent);
    color: #fff;
    border-color: var(--accent);
}
.btn-choose-file:active {
    transform: scale(0.98);
}
.file-input-filename {
    font-size: 0.8rem;
    color: var(--text-secondary);
    max-width: 180px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/* ——— Каталог курсов: названия курсов хорошо видно ——— */
.student-course-card .student-course-title {
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.35;
    letter-spacing: -0.02em;
}
.course-card-link:hover .student-course-title {
    color: var(--accent);
}
.student-course-card .student-course-desc {
    font-size: 0.875rem;
    color: var(--text-secondary);
}
.student-course-card .student-course-meta {
    color: var(--text-secondary);
    font-size: 0.8rem;
}

/* ——— Успеваемость: страница ——— */
.performance-page .performance-course-title {
    font-size: 1.25rem;
    color: var(--text-primary);
}
.performance-badge-grade {
    background: var(--ai-subtle);
    color: var(--accent);
    font-weight: 600;
}
.performance-badge-tasks {
    background: var(--border);
    color: var(--text-primary);
    font-weight: 500;
}
.performance-status-done {
    color: var(--success);
    font-size: 1.25rem;
}
.performance-status-pending {
    color: var(--text-secondary);
    font-size: 1.25rem;
}
.performance-task-item {
    transition: border-color 0.2s ease, background 0.2s ease;
}
.performance-task-item:hover {
    border-color: var(--accent) !important;
    background: var(--ai-subtle) !important;
}

/* ——— Профиль: две колонки (слева — карточка пользователя и оплаты, справа — формы), снизу отступ ——— */
.profile-page { padding-bottom: 2.5rem; }
.profile-wrap {
    display: grid;
    grid-template-columns: 260px 1fr;
    gap: 1.5rem;
    align-items: start;
}
@media (max-width: 767px) {
    .profile-wrap { grid-template-columns: 1fr; }
}
.profile-proftest {
    background: linear-gradient(135deg, rgba(99,102,241,0.12), rgba(139,92,246,0.08));
    border: 1px solid rgba(99,102,241,0.25);
    border-radius: 14px;
    padding: 1.25rem 1.5rem;
    margin-bottom: 1.5rem;
}
.profile-proftest-inner { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 1rem; }
.profile-proftest-title { font-size: 1rem; font-weight: 700; color: var(--accent); margin-bottom: 0.25rem; }
.profile-proftest-text { font-size: 0.875rem; color: var(--text-secondary); margin: 0; }
.profile-proftest-dismiss { color: var(--text-secondary) !important; font-size: 0.8rem; }

/* Левая колонка */
.profile-sidebar { display: flex; flex-direction: column; gap: 1.5rem; }
.profile-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 1.25rem 1.5rem;
    box-shadow: 0 2px 10px rgba(0,0,0,0.04);
}
[data-theme="dark"] .profile-card { box-shadow: 0 2px 16px rgba(0,0,0,0.2); }
.profile-card-user { text-align: center; }
.profile-avatar {
    width: 72px;
    height: 72px;
    margin: 0 auto 0.75rem;
    border-radius: 50%;
    background: var(--ai-gradient);
    color: #fff;
    font-size: 1.5rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 8px 24px rgba(99,102,241,0.35);
}
.profile-name { font-size: 1.1rem; font-weight: 700; margin: 0 0 0.25rem; line-height: 1.3; }
.profile-email { font-size: 0.8rem; color: var(--text-secondary); margin: 0; }
.profile-card-link { padding: 0; overflow: hidden; }

/* Правая колонка */
.profile-main { display: flex; flex-direction: column; gap: 1.5rem; }
.profile-section {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 1.35rem 1.5rem;
    box-shadow: 0 2px 12px rgba(0,0,0,0.04);
}
[data-theme="dark"] .profile-section { box-shadow: 0 2px 20px rgba(0,0,0,0.2); }
.profile-section-title {
    font-size: 0.9375rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: 0 0 1rem 0;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}
.profile-section-title i { color: var(--accent); opacity: 0.95; }
.profile-section-desc { font-size: 0.8125rem; color: var(--text-secondary); margin: 0; line-height: 1.45; }
.profile-section-compact .profile-section-title { margin-bottom: 0.35rem; }
.profile-section-row { display: flex; flex-wrap: wrap; align-items: flex-start; justify-content: space-between; gap: 1rem; }
.profile-form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem 1.25rem; margin-bottom: 1.25rem; }
@media (max-width: 576px) { .profile-form-grid { grid-template-columns: 1fr; } }
.profile-field-full { grid-column: 1 / -1; }
.profile-label { font-size: 0.75rem; font-weight: 600; color: var(--text-secondary); margin-bottom: 0.35rem; display: block; }
.profile-input {
    width: 100%;
    padding: 0.6rem 0.85rem;
    border-radius: 10px;
    border: 1px solid var(--border);
    background: var(--bg-secondary);
    color: var(--text-primary);
    font-size: 0.9375rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}
.profile-input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(99,102,241,0.15); outline: none; }
.profile-section-link { padding: 0; overflow: hidden; }
.profile-link-block {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 1.5rem;
    color: inherit;
    text-decoration: none;
    transition: background 0.2s;
}
.profile-link-block:hover { background: var(--ai-subtle); color: inherit; }
.profile-link-icon {
    width: 40px;
    height: 40px;
    border-radius: 10px;
    background: rgba(99,102,241,0.12);
    color: var(--accent);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}
.profile-link-text { font-weight: 600; flex: 1; }
.profile-link-arrow { color: var(--text-secondary); font-size: 0.9rem; }