/* ============================================================
   LingoTone MVC - site.css
   Glassmorphism + Gradient Design System
   Giữ nguyên 100% phong cách từ file HTML mẫu
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:opsz,wght@14..32,300;400;500;600;700;800&display=swap');

/* ===== RESET & BASE ===== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Inter', sans-serif;
}

:root {
    --primary: #10B981;
    --secondary: #3B82F6;
    --accent: #F59E0B;
    --danger: #EF4444;
    --bg-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --dark-bg: linear-gradient(135deg, #1e293b 0%, #0f172a 100%);
    --glass-bg: rgba(255, 255, 255, 0.85);
    --glass-border: rgba(255, 255, 255, 0.3);
    --sidebar-width: 280px;
    --header-height: 72px;
}

html, body {
    height: 100%;
    overflow: hidden;
}

body {
    background:
        radial-gradient(circle at 15% 10%, rgba(16,185,129,0.22), transparent 28%),
        radial-gradient(circle at 85% 20%, rgba(59,130,246,0.20), transparent 30%),
        linear-gradient(135deg, #eef6ff 0%, #f4f7ff 45%, #f7f3ff 100%);
    color: #172033;
}

/* ===== SCROLLBAR ===== */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: rgba(0,0,0,0.05); border-radius: 10px; }
::-webkit-scrollbar-thumb { background: rgba(16,185,129,0.4); border-radius: 10px; }
::-webkit-scrollbar-thumb:hover { background: rgba(16,185,129,0.6); }

/* ===== ANIMATIONS ===== */
@keyframes slideIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}
@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}
@keyframes bounceIn {
    0% { transform: scale(0.8); opacity: 0; }
    60% { transform: scale(1.05); opacity: 1; }
    100% { transform: scale(1); }
}
@keyframes flipCard {
    from { transform: rotateY(0deg); }
    to { transform: rotateY(180deg); }
}
@keyframes xpPop {
    0% { transform: scale(1); }
    50% { transform: scale(1.3); color: #10B981; }
    100% { transform: scale(1); }
}

.animate-slide-in { animation: slideIn 0.5s ease-out forwards; }
.animate-fade-in { animation: fadeIn 0.3s ease-out; }
.animate-bounce-in { animation: bounceIn 0.4s ease-out; }
.animate-pulse { animation: pulse 2s infinite; }

.glass-card,
.edtech-card,
.lesson-card,
.character-card,
.grammar-card,
.feature-card,
.hero-demo-card {
    background: rgba(255, 255, 255, 0.94) !important;
    backdrop-filter: blur(18px);
    border: 1px solid rgba(255,255,255,0.65);
    box-shadow: 0 18px 45px rgba(15, 23, 42, 0.10);
    border-radius: 24px;
    transition: all 0.3s ease;
}

.glass-card:hover,
.lesson-card:hover,
.character-card:hover,
.grammar-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 25px 60px rgba(15, 23, 42, 0.18);
}

/* ===== APP LAYOUT ===== */
#app-wrapper {
    display: flex;
    height: 100vh;
    overflow: hidden;
}

/* ===== SIDEBAR ===== */
.sidebar {
    width: var(--sidebar-width);
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
    z-index: 20;
    border-radius: 0 16px 16px 0;
    overflow-y: auto;
    overflow-x: hidden;
    background: rgba(255,255,255,0.86) !important;
}

.auth-modal-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(15, 23, 42, 0.55);
    backdrop-filter: blur(8px);
    z-index: 9999;
    align-items: center;
    justify-content: center;
}

.auth-modal-overlay.show {
    display: flex;
}

.auth-modal-card {
    width: min(420px, 92vw);
    padding: 28px;
    border-radius: 24px;
    background: rgba(255, 255, 255, 0.88);
    backdrop-filter: blur(16px);
    box-shadow: 0 25px 60px rgba(0, 0, 0, 0.25);
    text-align: center;
    animation: slideIn 0.25s ease-out;
}

.auth-modal-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto 16px;
    border-radius: 20px;
    background: linear-gradient(135deg, #10B981, #3B82F6);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
}

.auth-modal-actions {
    display: flex;
    gap: 12px;
    margin-top: 22px;
}

.auth-modal-actions a,
.auth-modal-actions button {
    flex: 1;
    border: none;
    border-radius: 14px;
    padding: 12px;
    font-weight: 700;
    cursor: pointer;
    text-decoration: none;
}

.auth-login-btn {
    background: linear-gradient(135deg, #10B981, #3B82F6);
    color: white;
}

.auth-register-btn {
    background: rgba(15, 23, 42, 0.08);
    color: #1f2937;
}

.header-search {
    width: min(540px, 45vw);
    height: 48px;
    border-radius: 999px;
    padding: 0 8px 0 20px;
    display: flex;
    align-items: center;
    gap: 10px;
    background: white;
    border: 1px solid rgba(0,0,0,0.05);
    box-shadow: 0 2px 12px rgba(0,0,0,0.03);
}

.header-search input {
    border: none;
    outline: none;
    background: transparent;
    width: 100%;
    font-size: 14px;
}

.sidebar .menu-item i {
    width: 22px;
    text-align: center;
    font-size: 15px;
}

.landing-hero {
    display: grid;
    grid-template-columns: 1.05fr 0.95fr;
    gap: 42px;
    align-items: center;
    min-height: 520px;
}

.hero-title {
    font-size: clamp(42px, 5vw, 72px);
    line-height: 1.05;
    font-weight: 900;
    color: #111827 !important;
}

.hero-description {
    font-size: 18px;
    line-height: 1.8;
    color: #4b5563;
    max-width: 620px;
}

.text-muted, p {
    color: #4b5563;
}

.hero-demo-card {
    max-width: 420px;
    margin: auto;
    padding: 34px;
    text-align: center;
}

.chinese-big {
    font-size: 88px;
    font-weight: 900;
    color: #111827;
}

.pinyin-text {
    color: #10B981;
    font-size: 24px;
    font-weight: 800;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 22px;
    margin-top: 36px;
}

.feature-card {
    padding: 24px;
    border-radius: 24px;
    background: rgba(255,255,255,0.84);
    transition: 0.25s ease;
    min-height: 190px;
}

.feature-card:hover {
    transform: translateY(-6px);
}

.lesson-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 24px;
}

.lesson-card {
    padding: 24px;
    position: relative;
    overflow: hidden;
}

.lesson-number {
    width: 48px;
    height: 48px;
    border-radius: 14px;
    background: linear-gradient(135deg, #10B981, #3B82F6);
    color: white;
    display: grid;
    place-items: center;
    font-weight: 900;
}

.character-grid {
    display: grid;
    grid-template-columns: repeat(6, minmax(0, 1fr));
    gap: 18px;
}

.character-card {
    min-height: 148px;
    text-align: center;
    padding: 24px 16px;
    cursor: pointer;
}

.character-card .hanzi {
    font-size: 52px;
    font-weight: 900;
    color: #111827;
}

.hsk-badge {
    display: inline-block;
    padding: 4px 10px;
    border-radius: 999px;
    background: rgba(16,185,129,0.16);
    color: #059669;
    font-size: 12px;
    font-weight: 800;
}

@media (max-width: 1100px) {
    .landing-hero,
    .lesson-grid {
        grid-template-columns: 1fr;
    }

    .feature-grid,
    .character-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .header-search {
        display: none;
    }
}

.sidebar-brand {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 24px;
    border-bottom: 1px solid rgba(255,255,255,0.2);
}

.sidebar-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
}

.sidebar-logo-icon {
    width: 40px;
    height: 40px;
    border-radius: 12px;
    background: linear-gradient(135deg, #10B981, #3B82F6);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 12px rgba(16,185,129,0.3);
    flex-shrink: 0;
}

.sidebar-logo-icon span {
    color: white;
    font-weight: 800;
    font-size: 20px;
}

.sidebar-logo-text h1 {
    font-size: 18px;
    font-weight: 800;
    background: linear-gradient(135deg, #10B981, #3B82F6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.2;
}

.sidebar-logo-text p {
    font-size: 11px;
    color: #64748b;
    margin-top: 2px;
}

/* ===== NAV MENU ===== */
.sidebar-nav {
    flex: 1;
    padding: 24px 0;
    overflow-y: auto;
}

.nav-section-label {
    padding: 0 24px;
    font-size: 11px;
    font-weight: 600;
    color: #94a3b8;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: 8px;
    margin-top: 8px;
}

.menu-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 24px;
    color: #4a5568;
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    position: relative;
    cursor: pointer;
    transition: all 0.3s ease;
}

.menu-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 3px;
    height: 0;
    background: linear-gradient(135deg, #10B981, #3B82F6);
    border-radius: 0 4px 4px 0;
    transition: height 0.3s ease;
}

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

.menu-item.active {
    background: linear-gradient(135deg, rgba(16,185,129,0.1), rgba(59,130,246,0.1));
    color: #10B981;
}

.menu-item:hover:not(.active) {
    background: rgba(0,0,0,0.05);
    transform: translateX(4px);
    color: #10B981;
}

.menu-item i {
    width: 20px;
    text-align: center;
    font-size: 15px;
}

.menu-badge {
    margin-left: auto;
    background: rgba(16,185,129,0.2);
    color: #10B981;
    font-size: 11px;
    padding: 2px 8px;
    border-radius: 20px;
    font-weight: 600;
}

/* ===== SIDEBAR USER FOOTER ===== */
.sidebar-user {
    padding: 16px;
    border-top: 1px solid rgba(255,255,255,0.2);
}

.sidebar-user-card {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px;
    border-radius: 12px;
    background: linear-gradient(135deg, rgba(16,185,129,0.1), rgba(59,130,246,0.1));
}

.avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: linear-gradient(135deg, #10B981, #3B82F6);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 700;
    font-size: 16px;
    flex-shrink: 0;
}

.sidebar-user-info p:first-child {
    font-size: 14px;
    font-weight: 600;
    color: #1e293b;
}

.sidebar-user-info p:last-child {
    font-size: 12px;
    color: #64748b;
}

/* ===== MAIN CONTENT AREA ===== */
.main-content,
.content-wrapper,
main {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    min-width: 0;
    padding: 32px;
    background: transparent !important;
}

.page-shell {
    background: rgba(255,255,255,0.35);
    border-radius: 32px;
    padding: 32px;
}

/* ===== HEADER ===== */
.site-header,
.app-header,
.top-header,
header {
    margin: 24px 32px 0 32px;
    padding: 12px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-radius: 24px;
    flex-shrink: 0;
    border: 1px solid rgba(255,255,255,0.65);
    background: rgba(255,255,255,0.94) !important;
    backdrop-filter: blur(18px);
    box-shadow: 0 18px 45px rgba(15, 23, 42, 0.08);
}

.header-greeting {
    display: flex;
    align-items: center;
    gap: 16px;
}

.header-greeting-emoji { font-size: 24px; }

.header-greeting-text p:first-child {
    font-size: 13px;
    color: #64748b;
}

.header-greeting-text p:last-child {
    font-size: 16px;
    font-weight: 600;
    color: #1e293b;
}

.header-stats {
    display: flex;
    align-items: center;
    gap: 12px;
}

.stat-badge {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 6px 12px;
    border-radius: 8px;
    font-size: 13px;
    font-weight: 600;
}

.stat-badge.fire { background: #fff7ed; color: #ea580c; }
.stat-badge.star { background: #eff6ff; color: #2563eb; }
.stat-badge.xp { background: #f0fdf4; color: #16a34a; }

.xp-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: #22c55e;
    animation: pulse 2s infinite;
}

.theme-btn {
    width: 36px;
    height: 36px;
    border-radius: 8px;
    border: none;
    background: transparent;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.2s;
    color: #64748b;
    font-size: 16px;
}

.theme-btn:hover { background: rgba(0,0,0,0.05); }

/* ===== PAGE CONTENT ===== */
.page-content {
    flex: 1;
    overflow-y: auto;
    padding: 32px;
}

.page-title {
    color: #172033;
    font-weight: 900;
    letter-spacing: -0.5px;
    margin-bottom: 24px;
    font-size: 26px;
}

/* ===== GRID LAYOUTS ===== */
.grid-3col { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.grid-2col { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.grid-4col { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.grid-lessons { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.grid-chars { display: grid; grid-template-columns: repeat(6, 1fr); gap: 16px; }
.grid-grammar { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }

/* ===== CARDS ===== */
.card {
    border-radius: 16px;
    padding: 24px;
    box-shadow: 0 4px 24px rgba(0,0,0,0.06);
}

/* Hero/Welcome Card */
.hero-card {
    border-radius: 20px;
    padding: 28px;
    background: linear-gradient(135deg, #10B981 0%, #3B82F6 60%, #F59E0B 100%);
    color: white;
    position: relative;
    overflow: hidden;
    box-shadow: 0 8px 32px rgba(16,185,129,0.3);
}

.hero-card::before {
    content: '';
    position: absolute;
    top: -60px;
    right: -60px;
    width: 200px;
    height: 200px;
    border-radius: 50%;
    background: rgba(255,255,255,0.1);
    filter: blur(30px);
}

.hero-card .welcome-text { font-size: 13px; opacity: 0.9; margin-bottom: 4px; }
.hero-card h2 { font-size: 24px; font-weight: 800; margin-bottom: 8px; }
.hero-card .quote { font-size: 13px; opacity: 0.9; margin-bottom: 20px; }

.hero-btn {
    display: inline-block;
    padding: 8px 20px;
    background: rgba(255,255,255,0.2);
    backdrop-filter: blur(10px);
    border-radius: 12px;
    color: white;
    font-size: 13px;
    font-weight: 600;
    text-decoration: none;
    border: none;
    cursor: pointer;
    transition: all 0.3s;
}
.hero-btn:hover { background: rgba(255,255,255,0.35); transform: scale(1.03); color: white; }

/* Stats Grid Card */
.stats-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
}

.stat-item {
    padding: 12px;
    border-radius: 12px;
}
.stat-item.orange { background: linear-gradient(135deg, #fff7ed, rgba(255,237,213,0.5)); }
.stat-item.blue { background: linear-gradient(135deg, #eff6ff, rgba(219,234,254,0.5)); }
.stat-item.green { background: linear-gradient(135deg, #f0fdf4, rgba(220,252,231,0.5)); }
.stat-item.purple { background: linear-gradient(135deg, #faf5ff, rgba(233,213,255,0.5)); }
.stat-item p:first-child { font-size: 11px; color: #64748b; margin-bottom: 4px; }
.stat-item .stat-value { font-size: 26px; font-weight: 800; color: #1e293b; }

/* Current Lesson Card */
.lesson-img-wrapper {
    height: 160px;
    border-radius: 12px;
    overflow: hidden;
    position: relative;
    margin-bottom: 16px;
    background: linear-gradient(135deg, #10B981, #3B82F6);
    display: flex;
    align-items: center;
    justify-content: center;
}

.lesson-img-wrapper img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.lesson-img-overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(to top, rgba(0,0,0,0.6), transparent);
}

.lesson-img-label {
    position: absolute;
    bottom: 12px;
    left: 12px;
    color: white;
    font-weight: 600;
    font-size: 14px;
}

.lesson-img-icon {
    font-size: 48px;
    opacity: 0.8;
}

/* Progress Bar */
.progress-bar-wrapper {
    margin-bottom: 12px;
}

.progress-label {
    display: flex;
    justify-content: space-between;
    font-size: 13px;
    margin-bottom: 6px;
    color: #64748b;
}

.progress-label .progress-pct {
    font-weight: 700;
    color: #10B981;
}

.progress-track {
    width: 100%;
    height: 8px;
    background: #e2e8f0;
    border-radius: 999px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    border-radius: 999px;
    background: linear-gradient(90deg, #10B981, #3B82F6);
    transition: width 0.8s ease;
}

.progress-fill.thin {
    height: 6px;
}

/* ===== MISSION LIST ===== */
.mission-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 8px 0;
}

.mission-check {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    border: 2px solid #cbd5e1;
    flex-shrink: 0;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
    background: white;
}

.mission-check:hover { border-color: #10B981; }
.mission-check.done { background: #10B981; border-color: #10B981; color: white; font-size: 10px; }

.mission-label { font-size: 14px; color: #374151; flex: 1; }
.mission-label.done { text-decoration: line-through; color: #94a3b8; }
.mission-xp { font-size: 12px; color: #10B981; font-weight: 600; margin-left: auto; }

/* ===== QUICK ACTIONS ===== */
.quick-actions-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
}

.quick-btn {
    padding: 16px 12px;
    border-radius: 12px;
    background: #f8fafc;
    border: none;
    cursor: pointer;
    text-align: center;
    text-decoration: none;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
}

.quick-btn:hover {
    background: linear-gradient(135deg, rgba(16,185,129,0.1), rgba(59,130,246,0.1));
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

.quick-btn i { font-size: 20px; color: #10B981; }
.quick-btn p { font-size: 12px; font-weight: 500; color: #374151; }

/* ===== ACTIVITY LIST ===== */
.activity-item {
    display: flex;
    gap: 12px;
    padding: 8px 0;
    border-bottom: 1px solid rgba(0,0,0,0.04);
}
.activity-item:last-child { border-bottom: none; }

.activity-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: #10B981;
    margin-top: 6px;
    flex-shrink: 0;
}

.activity-text { font-size: 13px; color: #374151; }
.activity-time { font-size: 11px; color: #94a3b8; margin-top: 2px; }

/* ===== ACHIEVEMENT BADGES ===== */
.achievement-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 8px 0;
}
.achievement-emoji { font-size: 24px; }
.achievement-info { flex: 1; }
.achievement-label { display: flex; justify-content: space-between; font-size: 13px; margin-bottom: 4px; }
.achievement-count { font-size: 12px; color: #64748b; }

/* ===== LESSON CARDS ===== */
.lesson-card {
    border-radius: 16px;
    padding: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.lesson-card:hover {
    transform: translateY(-4px) scale(1.01);
    box-shadow: 0 16px 40px rgba(0,0,0,0.12);
}

.lesson-card-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 12px;
}

.lesson-number {
    width: 40px;
    height: 40px;
    border-radius: 10px;
    background: linear-gradient(135deg, #10B981, #3B82F6);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 800;
    font-size: 16px;
    flex-shrink: 0;
}

.lesson-card h3 { font-size: 17px; font-weight: 700; color: #1e293b; }
.lesson-card p { font-size: 13px; color: #64748b; margin-bottom: 12px; }

.lesson-status {
    font-size: 12px;
    font-weight: 600;
    margin-top: 6px;
}
.lesson-status.completed { color: #10B981; }
.lesson-status.pending { color: #64748b; }

/* ===== CHARACTER GRID ===== */
.char-card {
    border-radius: 12px;
    padding: 16px 12px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.char-card:hover {
    border-color: #10B981;
    transform: translateY(-4px) scale(1.05);
    box-shadow: 0 8px 24px rgba(16,185,129,0.2);
}

.char-chinese { font-size: 36px; font-weight: 700; color: #1e293b; margin-bottom: 4px; }
.char-pinyin { font-size: 12px; color: #10B981; font-weight: 600; margin-bottom: 2px; }
.char-meaning { font-size: 11px; color: #64748b; }
.char-hsk {
    display: inline-block;
    font-size: 10px;
    padding: 2px 6px;
    border-radius: 20px;
    background: rgba(16,185,129,0.1);
    color: #10B981;
    margin-top: 4px;
    font-weight: 600;
}

/* ===== CHARACTER SEARCH ===== */
.search-bar {
    display: flex;
    gap: 16px;
    margin-bottom: 24px;
}

.search-input {
    flex: 1;
    padding: 10px 18px;
    border-radius: 12px;
    border: 1px solid rgba(255,255,255,0.3);
    background: rgba(255,255,255,0.6);
    font-size: 14px;
    outline: none;
    transition: all 0.3s;
}
.search-input:focus {
    border-color: #10B981;
    background: rgba(255,255,255,0.9);
    box-shadow: 0 0 0 3px rgba(16,185,129,0.1);
}

.filter-select {
    padding: 10px 18px;
    border-radius: 12px;
    border: 1px solid rgba(255,255,255,0.3);
    background: rgba(255,255,255,0.6);
    font-size: 14px;
    outline: none;
    cursor: pointer;
    min-width: 130px;
}
.filter-select:focus {
    border-color: #10B981;
}

/* ===== CHARACTER MODAL ===== */
.char-modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    animation: fadeIn 0.2s ease;
}

.char-modal {
    border-radius: 20px;
    padding: 32px;
    max-width: 400px;
    width: 90%;
    animation: bounceIn 0.3s ease;
}

.char-modal-big { font-size: 80px; font-weight: 800; text-align: center; margin-bottom: 16px; }
.char-modal-row { display: flex; justify-content: space-between; padding: 8px 0; border-bottom: 1px solid rgba(0,0,0,0.05); font-size: 14px; }
.char-modal-row:last-child { border-bottom: none; }
.char-modal-row span:first-child { color: #64748b; }
.char-modal-row span:last-child { font-weight: 600; color: #1e293b; }

/* ===== GRAMMAR CARDS ===== */
.grammar-card {
    border-radius: 16px;
    padding: 20px;
    margin-bottom: 0;
    cursor: pointer;
    transition: all 0.3s ease;
    border-left: 4px solid #10B981;
}

.grammar-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.08);
}

.grammar-card h3 { font-size: 16px; font-weight: 700; color: #1e293b; margin-bottom: 8px; }
.grammar-pattern {
    display: inline-block;
    padding: 4px 12px;
    background: rgba(16,185,129,0.1);
    color: #10B981;
    border-radius: 8px;
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 12px;
}
.grammar-example { font-size: 20px; font-weight: 700; color: #1e293b; margin-bottom: 4px; }
.grammar-pinyin { font-size: 13px; color: #10B981; margin-bottom: 2px; }
.grammar-meaning { font-size: 13px; color: #64748b; }

/* ===== QUIZ STYLES ===== */
.quiz-question {
    font-size: 20px;
    font-weight: 700;
    color: #1e293b;
    margin-bottom: 28px;
    text-align: center;
}

.quiz-options {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin-bottom: 24px;
}

.quiz-option {
    padding: 16px 20px;
    border-radius: 12px;
    border: 2px solid #e2e8f0;
    background: white;
    font-size: 15px;
    font-weight: 500;
    cursor: pointer;
    text-align: center;
    transition: all 0.25s ease;
    color: #374151;
}

.quiz-option:hover:not(.selected):not(.correct):not(.wrong) {
    border-color: #10B981;
    background: rgba(16,185,129,0.05);
    transform: translateY(-2px);
}

.quiz-option.selected { border-color: #3B82F6; background: rgba(59,130,246,0.1); color: #2563eb; }
.quiz-option.correct { border-color: #10B981; background: rgba(16,185,129,0.15); color: #065f46; }
.quiz-option.wrong { border-color: #EF4444; background: rgba(239,68,68,0.1); color: #b91c1c; }

.quiz-progress {
    margin-bottom: 20px;
}

.quiz-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 8px;
    font-size: 13px;
    color: #64748b;
}

.quiz-score-badge {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 4px 10px;
    background: rgba(16,185,129,0.1);
    color: #10B981;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 600;
}

.quiz-result {
    text-align: center;
    animation: bounceIn 0.5s ease;
}

.quiz-result-emoji { font-size: 64px; margin-bottom: 16px; }
.quiz-result h3 { font-size: 26px; font-weight: 800; color: #1e293b; margin-bottom: 8px; }
.quiz-result .xp-earned { font-size: 20px; font-weight: 700; color: #10B981; margin-bottom: 20px; }
.quiz-result p { font-size: 15px; color: #64748b; margin-bottom: 24px; }

.btn-primary,
.btn-gradient {
    display: inline-block;
    padding: 12px 28px;
    border-radius: 12px;
    background: linear-gradient(135deg, #10B981, #3B82F6) !important;
    color: white;
    font-size: 14px;
    font-weight: 600;
    border: none;
    box-shadow: 0 12px 28px rgba(59,130,246,0.22);
    cursor: pointer;
    text-decoration: none;
    transition: all 0.3s ease;
}
.btn-primary:hover { transform: scale(1.05); box-shadow: 0 8px 20px rgba(16,185,129,0.3); color: white; }

.btn-secondary {
    display: inline-block;
    padding: 12px 28px;
    border-radius: 12px;
    background: #f1f5f9;
    color: #374151;
    font-size: 14px;
    font-weight: 600;
    border: none;
    cursor: pointer;
    text-decoration: none;
    transition: all 0.3s ease;
    margin-right: 12px;
}
.btn-secondary:hover { background: #e2e8f0; transform: scale(1.02); color: #374151; }

/* ===== SRS FLASHCARD ===== */
.srs-container {
    max-width: 560px;
    margin: 0 auto;
    text-align: center;
}

.flashcard-wrapper {
    perspective: 1200px;
    margin-bottom: 32px;
}

.flashcard {
    position: relative;
    width: 100%;
    min-height: 260px;
    cursor: pointer;
    transform-style: preserve-3d;
    transition: transform 0.6s ease;
}

.flashcard.flipped { transform: rotateY(180deg); }

.flashcard-face {
    position: absolute;
    width: 100%;
    min-height: 260px;
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
    border-radius: 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 40px;
    box-shadow: 0 8px 32px rgba(0,0,0,0.1);
}

.flashcard-front {
    background: linear-gradient(135deg, rgba(255,255,255,0.9), rgba(240,253,244,0.9));
    border: 1px solid rgba(16,185,129,0.2);
}

.flashcard-back {
    background: linear-gradient(135deg, rgba(16,185,129,0.1), rgba(59,130,246,0.1));
    border: 1px solid rgba(59,130,246,0.2);
    transform: rotateY(180deg);
}

.flashcard-word { font-size: 56px; font-weight: 800; color: #1e293b; margin-bottom: 8px; }
.flashcard-pinyin { font-size: 20px; color: #10B981; font-weight: 600; }
.flashcard-hint { font-size: 13px; color: #94a3b8; margin-top: 20px; }
.flashcard-meaning { font-size: 26px; font-weight: 700; color: #1e293b; margin-bottom: 12px; }
.flashcard-level { font-size: 13px; color: #64748b; }

.srs-actions {
    display: flex;
    gap: 16px;
    justify-content: center;
    margin-bottom: 20px;
}

.srs-btn {
    padding: 14px 32px;
    border-radius: 14px;
    border: none;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.25s ease;
    display: flex;
    align-items: center;
    gap: 8px;
}

.srs-btn.remember {
    background: linear-gradient(135deg, #10B981, #059669);
    color: white;
}
.srs-btn.remember:hover { transform: scale(1.05); box-shadow: 0 6px 20px rgba(16,185,129,0.4); }

.srs-btn.forget {
    background: linear-gradient(135deg, #EF4444, #dc2626);
    color: white;
}
.srs-btn.forget:hover { transform: scale(1.05); box-shadow: 0 6px 20px rgba(239,68,68,0.4); }

.srs-counter { font-size: 14px; color: #64748b; }

.srs-done {
    text-align: center;
    padding: 48px 0;
    animation: bounceIn 0.5s ease;
}
.srs-done i { font-size: 64px; color: #10B981; margin-bottom: 16px; display: block; }
.srs-done h3 { font-size: 24px; font-weight: 800; color: #1e293b; margin-bottom: 8px; }
.srs-done p { font-size: 15px; color: #64748b; }

/* ===== SRS LEVEL INDICATORS ===== */
.srs-levels {
    display: flex;
    gap: 6px;
    justify-content: center;
    margin-bottom: 16px;
}
.srs-level-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: #e2e8f0;
    transition: background 0.3s;
}
.srs-level-dot.filled { background: linear-gradient(135deg, #10B981, #3B82F6); }

/* ===== PROGRESS PAGE ===== */
.progress-stats-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin-bottom: 24px;
}

.progress-stat-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 0;
    border-bottom: 1px solid rgba(0,0,0,0.05);
}
.progress-stat-item:last-child { border-bottom: none; }
.progress-stat-item .label { font-size: 14px; color: #64748b; }
.progress-stat-item .value { font-size: 18px; font-weight: 700; color: #10B981; }

/* Weekly Chart */
.weekly-chart {
    display: flex;
    align-items: flex-end;
    gap: 10px;
    height: 180px;
    padding: 16px 0 8px;
}

.chart-bar-wrapper {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    height: 100%;
}

.chart-bar {
    width: 100%;
    border-radius: 6px 6px 0 0;
    background: linear-gradient(to top, #10B981, #3B82F6);
    min-height: 4px;
    transition: height 0.8s ease;
}

.chart-label { font-size: 11px; color: #94a3b8; margin-top: 4px; }
.chart-value { font-size: 11px; font-weight: 600; color: #374151; margin-top: 2px; }

/* ===== LESSON DETAIL ===== */
.back-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: #10B981;
    text-decoration: none;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 20px;
    transition: all 0.2s;
}
.back-btn:hover { color: #059669; transform: translateX(-2px); }

.lesson-detail-card { border-radius: 20px; padding: 32px; }

.vocab-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }
.vocab-tag {
    padding: 6px 14px;
    background: rgba(16,185,129,0.1);
    color: #065f46;
    border-radius: 8px;
    font-size: 15px;
    font-weight: 600;
}

.dialogue-box {
    background: rgba(0,0,0,0.03);
    border-radius: 12px;
    padding: 16px 20px;
    margin-top: 12px;
    font-size: 15px;
    line-height: 1.8;
    white-space: pre-line;
    color: #374151;
}

.complete-btn {
    margin-top: 24px;
    padding: 14px 32px;
    border-radius: 14px;
    background: linear-gradient(135deg, #10B981, #3B82F6);
    color: white;
    font-size: 15px;
    font-weight: 700;
    border: none;
    cursor: pointer;
    width: 100%;
    transition: all 0.3s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}
.complete-btn:hover { transform: scale(1.02); box-shadow: 0 8px 24px rgba(16,185,129,0.4); }
.complete-btn:disabled { opacity: 0.5; cursor: not-allowed; transform: none; }

/* ===== AUTH PAGES ===== */
.auth-page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-gradient);
    padding: 24px;
}

.auth-card {
    width: 100%;
    max-width: 420px;
    border-radius: 24px;
    padding: 40px;
    animation: slideIn 0.5s ease;
}

.auth-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 32px;
    justify-content: center;
}

.auth-logo-icon {
    width: 48px;
    height: 48px;
    border-radius: 14px;
    background: linear-gradient(135deg, #10B981, #3B82F6);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 16px rgba(16,185,129,0.3);
}

.auth-logo-icon span { color: white; font-size: 24px; font-weight: 800; }

.auth-title { font-size: 28px; font-weight: 800; color: #1e293b; text-align: center; margin-bottom: 6px; }
.auth-subtitle { font-size: 14px; color: #64748b; text-align: center; margin-bottom: 32px; }

.form-group { margin-bottom: 18px; }

.form-label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    color: #374151;
    margin-bottom: 6px;
}

.form-control {
    width: 100%;
    padding: 12px 16px;
    border-radius: 12px;
    border: 1.5px solid #e2e8f0;
    background: rgba(255,255,255,0.8);
    font-size: 14px;
    outline: none;
    transition: all 0.3s;
    color: #1e293b;
}
.form-control:focus {
    border-color: #10B981;
    background: white;
    box-shadow: 0 0 0 3px rgba(16,185,129,0.1);
}
.form-control.is-invalid {
    border-color: #EF4444;
}

.field-validation-error { font-size: 12px; color: #EF4444; margin-top: 4px; display: block; }

.auth-submit-btn {
    width: 100%;
    padding: 14px;
    border-radius: 12px;
    background: linear-gradient(135deg, #10B981, #3B82F6);
    color: white;
    font-size: 15px;
    font-weight: 700;
    border: none;
    cursor: pointer;
    transition: all 0.3s;
    margin-top: 8px;
}
.auth-submit-btn:hover { transform: scale(1.02); box-shadow: 0 8px 24px rgba(16,185,129,0.4); }

.auth-link { text-align: center; margin-top: 20px; font-size: 14px; color: #64748b; }
.auth-link a { color: #10B981; font-weight: 600; text-decoration: none; }
.auth-link a:hover { text-decoration: underline; }

.alert-error {
    padding: 12px 16px;
    background: rgba(239,68,68,0.1);
    border: 1px solid rgba(239,68,68,0.2);
    border-radius: 10px;
    color: #b91c1c;
    font-size: 13px;
    margin-bottom: 16px;
}

/* ===== TOAST NOTIFICATIONS ===== */
.toast {
    position: fixed;
    bottom: 24px;
    right: 24px;
    padding: 12px 20px;
    border-radius: 12px;
    font-size: 14px;
    font-weight: 600;
    z-index: 9999;
    animation: slideIn 0.3s ease;
    box-shadow: 0 8px 24px rgba(0,0,0,0.15);
    display: flex;
    align-items: center;
    gap: 8px;
    max-width: 320px;
}

.toast.success { background: rgba(16,185,129,0.95); color: white; }
.toast.error { background: rgba(239,68,68,0.95); color: white; }
.toast.info { background: rgba(59,130,246,0.95); color: white; }

/* ===== XP POPUP ===== */
.xp-popup {
    position: fixed;
    top: 80px;
    right: 24px;
    background: linear-gradient(135deg, #10B981, #3B82F6);
    color: white;
    padding: 12px 20px;
    border-radius: 12px;
    font-weight: 700;
    font-size: 16px;
    z-index: 9999;
    animation: slideIn 0.3s ease, fadeOut 0.4s 1.6s forwards;
    box-shadow: 0 8px 24px rgba(16,185,129,0.4);
}

@keyframes fadeOut {
    to { opacity: 0; transform: translateY(-20px); }
}

/* ===== DARK MODE ===== */
.dark body { background: var(--dark-bg) !important; }
.dark .glass-card { background: rgba(30, 41, 59, 0.85) !important; color: #e2e8f0; }
.dark .glass-card:hover { background: rgba(30, 41, 59, 0.95) !important; }
.dark .page-title, .dark .lesson-card h3, .dark .grammar-card h3 { color: #e2e8f0; }
.dark .text-gray-600, .dark .stat-label, .dark .label { color: #cbd5e1 !important; }
.dark .lesson-card p { color: #94a3b8; }
.dark .form-control { background: rgba(30,41,59,0.8); border-color: rgba(255,255,255,0.1); color: #e2e8f0; }
.dark .sidebar-user-info p:first-child { color: #e2e8f0; }
.dark .header-greeting-text p:last-child { color: #e2e8f0; }
.dark .char-chinese { color: #e2e8f0; }
.dark .quiz-option { background: rgba(30,41,59,0.9); border-color: rgba(255,255,255,0.1); color: #e2e8f0; }
.dark .dialogue-box { background: rgba(0,0,0,0.3); color: #e2e8f0; }
.dark .stat-value, .dark .char-modal-row span:last-child { color: #e2e8f0; }

/* ===== RESPONSIVE ===== */
@media (max-width: 1024px) {
    .grid-3col { grid-template-columns: repeat(2, 1fr); }
    .grid-chars { grid-template-columns: repeat(4, 1fr); }
}

@media (max-width: 768px) {
    .sidebar {
        width: 80px;
    }
    .sidebar .sidebar-logo-text,
    .sidebar .nav-section-label,
    .sidebar .menu-item span,
    .sidebar .menu-badge,
    .sidebar-user-info { display: none; }
    .sidebar .menu-item { justify-content: center; padding: 12px; }
    .sidebar .menu-item i { width: auto; }
    .sidebar-user-card { justify-content: center; }

    .grid-3col { grid-template-columns: 1fr; }
    .grid-2col { grid-template-columns: 1fr; }
    .grid-4col { grid-template-columns: 1fr 1fr; }
    .grid-lessons { grid-template-columns: 1fr; }
    .grid-chars { grid-template-columns: repeat(3, 1fr); }
    .grid-grammar { grid-template-columns: 1fr; }
    .quiz-options { grid-template-columns: 1fr; }

    .header-stats .stat-badge { display: none; }
    .page-content { padding: 16px; }
    .site-header { padding: 0 16px; }
}
.auth-modal-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(15, 23, 42, 0.55);
    backdrop-filter: blur(8px);
    z-index: 9999;
    align-items: center;
    justify-content: center;
}

.auth-modal-overlay.show {
    display: flex;
}

.auth-modal-card {
    width: min(420px, 92vw);
    padding: 28px;
    border-radius: 24px;
    background: rgba(255, 255, 255, 0.88);
    backdrop-filter: blur(16px);
    box-shadow: 0 25px 60px rgba(0, 0, 0, 0.25);
    text-align: center;
    animation: slideIn 0.25s ease-out;
}

.auth-modal-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto 16px;
    border-radius: 20px;
    background: linear-gradient(135deg, #10B981, #3B82F6);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
}

.auth-modal-actions {
    display: flex;
    gap: 12px;
    margin-top: 22px;
}

.auth-modal-actions a,
.auth-modal-actions button {
    flex: 1;
    border: none;
    border-radius: 14px;
    padding: 12px;
    font-weight: 700;
    cursor: pointer;
    text-decoration: none;
}

.auth-login-btn {
    background: linear-gradient(135deg, #10B981, #3B82F6);
    color: white;
}

.auth-register-btn {
    background: rgba(15, 23, 42, 0.08);
    color: #1f2937;
}



.landing-hero {
    min-height: calc(100vh - 110px);
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 32px;
    align-items: center;
}

.hero-title {
    font-size: clamp(42px, 6vw, 76px);
    line-height: 1.05;
    font-weight: 900;
    letter-spacing: -2px;
}

.hero-gradient-text {
    background: linear-gradient(135deg, #10B981, #3B82F6, #F59E0B);
    -webkit-background-clip: text;
    color: transparent;
}

.edtech-card {
    border-radius: 28px;
    background: rgba(255, 255, 255, 0.84);
    backdrop-filter: blur(18px);
    border: 1px solid rgba(255, 255, 255, 0.35);
    box-shadow: 0 24px 60px rgba(15, 23, 42, 0.16);
    transition: all 0.28s ease;
}

.edtech-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 30px 80px rgba(15, 23, 42, 0.22);
}

.quick-action-card {
    min-height: 130px;
    border-radius: 22px;
    background: rgba(255, 255, 255, 0.72);
    border: 1px solid rgba(255, 255, 255, 0.38);
    transition: 0.25s ease;
}

.quick-action-card:hover {
    transform: translateY(-5px) scale(1.01);
}

.search-shell {
    width: min(520px, 45vw);
    padding: 10px 16px;
    border-radius: 999px;
    background: rgba(255,255,255,0.58);
    border: 1px solid rgba(255,255,255,0.35);
    display: flex;
    align-items: center;
    gap: 10px;
}

.search-shell input {
    border: none;
    outline: none;
    background: transparent;
    width: 100%;
}

.mission-check {
    width: 22px;
    height: 22px;
    border-radius: 50%;
    border: 2px solid rgba(16,185,129,0.45);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
}

.mission-item.completed .mission-check {
    background: linear-gradient(135deg, #10B981, #3B82F6);
    color: white;
}

.mission-item.completed .mission-text {
    text-decoration: line-through;
    opacity: 0.6;
}

@media (max-width: 992px) {
    .landing-hero {
        grid-template-columns: 1fr;
    }

    .search-shell {
        display: none;
    }
}



/* ===== AI CAREER CHINESE WIDGET & MODAL ===== */
.career-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 15px;
    margin-top: 20px;
}
.career-option {
    background: rgba(255, 255, 255, 0.5);
    border: 1px solid rgba(255, 255, 255, 0.8);
    border-radius: 16px;
    padding: 20px 10px;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}
.career-option:hover {
    transform: translateY(-5px);
    background: rgba(255, 255, 255, 0.9);
    box-shadow: 0 10px 25px -5px rgba(59, 130, 246, 0.2);
    border-color: rgba(59, 130, 246, 0.3);
}
.career-icon {
    font-size: 32px;
}
.career-name {
    font-weight: 600;
    color: #334155;
    font-size: 14px;
}
.career-words-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
    gap: 15px;
    margin-top: 15px;
}
.career-word-card {
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 16px;
    padding: 15px;
    transition: all 0.2s ease;
    cursor: pointer;
}
.career-word-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.05);
    border-color: #cbd5e1;
}
.widget-glass {
    background: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.6);
    border-radius: 24px;
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.03);
}