/* shasui.com - Main Stylesheet - 沙穗教育 */
:root,[data-theme="light"] {
    --primary:#ffffff; --bg:#f0f2f5; --card:#ffffff;
    --text:#1a1a2e; --text-secondary:#666; --accent:#4a90d9;
    --accent-light:#e8f0fe; --border-color:#e0e0e0;
    --success:#4caf50; --warning:#ff9800; --danger:#f44336;
    --radius:12px; --shadow:0 2px 12px rgba(0,0,0,0.06);
    --transition:all 0.25s ease;
    --nav-bg:rgba(255,255,255,0.95);
}
[data-theme="dark"] {
    --primary:#1a1a2e; --bg:#121220; --card:#1e1e36;
    --text:#e0e0e0; --text-secondary:#999; --accent:#7c83ff;
    --accent-light:#1e1e3a; --border-color:#2a2a4a;
    --shadow:0 4px 20px rgba(0,0,0,0.4);
    --nav-bg:rgba(26,26,46,0.95);
}
[data-theme="warm"] {
    --primary:#fef9e7; --bg:#faf5eb; --card:#fef9e7;
    --text:#4a3728; --text-secondary:#8b7355; --accent:#c8843c;
    --accent-light:#fef3e4; --border-color:#e8d5c4;
    --shadow:0 2px 12px rgba(0,0,0,0.05);
    --nav-bg:rgba(255,253,242,0.95);
}
[data-theme="green"] {
    --primary:#e8f5e9; --bg:#eef4ed; --card:#e8f5e9;
    --text:#2e3b2e; --text-secondary:#5a6e5a; --accent:#388e3c;
    --accent-light:#e8f5e9; --border-color:#c8e6c9;
    --shadow:0 2px 12px rgba(46,125,50,0.08);
    --nav-bg:rgba(232,245,233,0.95);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: -apple-system, 'Microsoft YaHei', 'PingFang SC', sans-serif; background: var(--bg); color: var(--text); line-height: 1.6; min-height: 100vh; }
a { color: var(--accent); text-decoration: none; }
img { max-width: 100%; }

/* Header */
.site-header { background: var(--nav-bg); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); border-bottom: 1px solid var(--border-color); position: sticky; top: 0; z-index: 100; box-shadow: var(--shadow); }
.header-inner { max-width: 1200px; margin: 0 auto; display: flex; align-items: center; justify-content: space-between; padding: 8px 20px; gap: 16px; }
.logo { display: flex; align-items: center; gap: 8px; text-decoration: none; color: var(--text); white-space: nowrap; flex-shrink: 0; }
.logo-img { width: 38px; height: 38px; border-radius: 8px; object-fit: cover; }
.logo-text { font-size: 22px; font-weight: 800; letter-spacing: 2px; background: linear-gradient(135deg, var(--accent), #388e3c); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.main-nav { display: flex; gap: 2px; flex-wrap: nowrap; overflow-x: auto; }
.main-nav a { padding: 6px 12px; border-radius: 6px; color: var(--text-secondary); font-size: 13px; transition: var(--transition); white-space: nowrap; font-weight: 500; }
.main-nav a:hover { color: var(--accent); background: var(--accent-light); }
.main-nav a.active { background: var(--accent); color: #fff; font-weight: 600; }
.admin-link { color: #e94560 !important; }
.header-actions { display: flex; align-items: center; gap: 8px; flex-shrink: 0; }
/* Theme Toggle - 4-position radio */
.theme-toggle { display: flex; border-radius: 20px; overflow: hidden; border: 1px solid var(--border-color); background: var(--bg); }
.theme-toggle input { position: absolute; opacity: 0; pointer-events: none; }
.theme-toggle label { width: 32px; height: 30px; display: flex; align-items: center; justify-content: center; cursor: pointer; font-size: 14px; transition: var(--transition); position: relative; z-index: 1; }
.theme-toggle label:hover { background: var(--accent-light); }
.theme-toggle input:checked + label { background: var(--accent); transform: scale(1.1); border-radius: 20px; }
.mobile-menu-btn { display: none; background: none; border: none; color: var(--text); font-size: 24px; cursor: pointer; }
.user-menu { position: relative; }
.user-btn { display: flex; align-items: center; gap: 8px; background: var(--card); border: 1px solid var(--border-color); color: var(--text); padding: 6px 14px; border-radius: 20px; cursor: pointer; font-size: 14px; }
.user-avatar { display: inline-flex; width: 28px; height: 28px; border-radius: 50%; background: var(--accent); color: white; align-items: center; justify-content: center; font-size: 13px; font-weight: bold; }
.vip-badge { background: linear-gradient(135deg, gold, orange); color: #333; padding: 2px 8px; border-radius: 10px; font-size: 11px; font-weight: bold; }
.dropdown-menu { display: none; position: absolute; top: 100%; right: 0; background: var(--card); border: 1px solid var(--border-color); border-radius: var(--radius); min-width: 160px; box-shadow: var(--shadow); z-index: 200; }
.user-dropdown.open .dropdown-menu { display: block; }
.dropdown-menu a { display: block; padding: 10px 16px; color: var(--text); transition: var(--transition); }
.dropdown-menu a:hover { background: var(--bg); }
.upgrade-link { color: orange !important; font-weight: bold; }
.login-btn, .register-btn { padding: 8px 16px; border: none; border-radius: 8px; cursor: pointer; font-size: 14px; transition: var(--transition); }
.login-btn { background: var(--card); color: var(--text); border: 1px solid var(--border-color); }
.register-btn { background: var(--accent); color: white; }
.login-btn:hover { background: var(--bg); }
.register-btn:hover { opacity: 0.9; }

/* Main */
.site-main { max-width: 1200px; margin: 0 auto; padding: 30px 20px; min-height: 70vh; }
.container { max-width: 100%; }
.page-title { font-size: 28px; margin-bottom: 10px; }
.page-desc { color: var(--text); opacity: 0.7; margin-bottom: 30px; }

/* Buttons */
.btn-primary { display: inline-block; padding: 10px 24px; background: var(--accent); color: white; border: none; border-radius: var(--radius); cursor: pointer; font-size: 15px; transition: var(--transition); text-decoration: none; }
.btn-primary:hover { opacity: 0.9; transform: translateY(-1px); }
.btn-outline { display: inline-block; padding: 10px 24px; background: transparent; color: var(--accent); border: 2px solid var(--accent); border-radius: var(--radius); cursor: pointer; font-size: 15px; transition: var(--transition); }
.btn-outline:hover { background: var(--accent); color: white; }
.btn-success { display: inline-block; padding: 10px 24px; background: var(--success); color: white; border: none; border-radius: var(--radius); cursor: pointer; font-size: 15px; }
.btn-sm { padding: 6px 14px; font-size: 13px; border-radius: 8px; cursor: pointer; }
.btn-lg { padding: 14px 32px; font-size: 18px; }
.btn-block { width: 100%; }

/* Hero */
.hero-section { text-align: center; padding: 60px 20px; background: linear-gradient(135deg, var(--primary), var(--card)); border-radius: 20px; margin-bottom: 50px; }
.hero-content h1 { font-size: 48px; margin-bottom: 10px; }
.hero-subtitle { font-size: 20px; opacity: 0.8; margin-bottom: 10px; }
.hero-desc { font-size: 16px; opacity: 0.6; margin-bottom: 30px; }
.hero-actions { display: flex; gap: 15px; justify-content: center; flex-wrap: wrap; }
.hero-stats { display: flex; justify-content: center; gap: 40px; margin-top: 40px; flex-wrap: wrap; }
.stat-item { text-align: center; }
.stat-num { display: block; font-size: 36px; font-weight: bold; color: var(--accent); }
.stat-label { font-size: 14px; opacity: 0.7; }
@media (max-width: 768px) { .hero-content h1 { font-size: 32px; } .hero-stats { gap: 20px; } }

/* Sections */
.section-title { text-align: center; font-size: 26px; margin: 36px 0 20px; }
.feature-cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 20px; margin-bottom: 40px; }
.feature-card { background: var(--card); border-radius: var(--radius); padding: 30px; cursor: pointer; transition: var(--transition); border: 2px solid transparent; }
.feature-card:hover { border-color: var(--accent); transform: translateY(-4px); box-shadow: var(--shadow); }
.feature-icon { font-size: 40px; margin-bottom: 15px; }
.feature-card h3 { margin-bottom: 10px; }
.feature-card p { opacity: 0.7; font-size: 14px; margin-bottom: 15px; }
.feature-card.feature-card-coming { opacity: 0.5; cursor: default; background: var(--card); border: 2px dashed var(--border); }
.feature-card.feature-card-coming:hover { border-color: var(--accent); opacity: 0.7; transform: none; }
.feature-link-disabled { opacity: 0.4; }
.feature-link { color: var(--accent); font-size: 14px; font-weight: bold; }

/* Grade Grid */
.grade-grid { display: flex; flex-wrap: wrap; gap: 12px; justify-content: center; margin-bottom: 8px; }
.grade-card { display: flex; flex-direction: column; align-items: center; padding: 20px; background: var(--card); border-radius: var(--radius); transition: var(--transition); min-width: 100px; }
.grade-card:hover { background: var(--accent); color: white; transform: translateY(-2px); }
.grade-icon { font-size: 28px; margin-bottom: 8px; }
.grade-name { font-size: 15px; font-weight: bold; }

/* CTA */
.cta-section { text-align: center; padding: 60px 20px; background: linear-gradient(135deg, var(--card), var(--primary)); border-radius: 20px; margin: 50px 0; }
.cta-prices { display: flex; gap: 20px; justify-content: center; margin: 30px 0; flex-wrap: wrap; }
.price-card { background: var(--bg); padding: 30px; border-radius: var(--radius); min-width: 180px; border: 2px solid var(--border-color); position: relative; }
.price-card.recommended { border-color: gold; }
.recommended-badge { position: absolute; top: -12px; left: 50%; transform: translateX(-50%); background: gold; color: #333; padding: 2px 16px; border-radius: 12px; font-size: 12px; font-weight: bold; }
.price { font-size: 36px; font-weight: bold; color: var(--accent); }

/* Filter bar */
.filter-bar { display: flex; gap: 10px; margin-bottom: 30px; flex-wrap: wrap; align-items: center; }
.filter-bar select { padding: 10px 16px; border: 1px solid var(--border-color); border-radius: var(--radius); background: var(--card); color: var(--text); font-size: 14px; }

/* Grids */
.lessons-grid, .ebooks-grid, .papers-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 20px; }
@media (max-width: 480px) { .lessons-grid, .ebooks-grid, .papers-grid { grid-template-columns: 1fr; } }
.lesson-card, .paper-card, .game-card { background: var(--card); border-radius: var(--radius); padding: 20px; transition: var(--transition); border: 2px solid transparent; }
.lesson-card:hover, .paper-card:hover, .game-card:hover { border-color: var(--accent); }
.lesson-meta, .paper-meta { display: flex; gap: 10px; flex-wrap: wrap; margin: 10px 0; font-size: 13px; opacity: 0.7; }
.lesson-actions, .paper-actions { display: flex; gap: 10px; margin-top: 15px; }

.ebook-card { display: flex; gap: 16px; background: var(--card); border-radius: var(--radius); padding: 16px; transition: var(--transition); }
.ebook-card:hover { border-color: var(--accent); }
.ebook-cover img { width: 80px; height: 110px; object-fit: cover; border-radius: 8px; }
.cover-placeholder { width: 80px; height: 110px; background: var(--bg); border-radius: 8px; display: flex; align-items: center; justify-content: center; font-size: 30px; }
.ebook-info { flex: 1; }
.ebook-meta { display: flex; gap: 15px; font-size: 12px; opacity: 0.7; margin: 8px 0; }
.ebook-actions { display: flex; gap: 8px; margin-top: 10px; }

.games-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 20px; }
.game-card { text-align: center; padding: 30px; cursor: pointer; }
.game-icon { font-size: 50px; margin-bottom: 15px; }

.paper-type { display: inline-block; padding: 3px 10px; border-radius: 4px; font-size: 12px; font-weight: bold; }
.type-unit { background: #e3f2fd; color: #1976d2; }
.type-monthly { background: #e8f5e9; color: #388e3c; }
.type-midterm { background: #fff3e0; color: #f57c00; }
.type-final { background: #fce4ec; color: #c62828; }
.type-mock { background: #f3e5f5; color: #7b1fa2; }

/* Quiz */
.quiz-setup { text-align: center; max-width: 500px; margin: 0 auto; }
.question-area { margin: 20px 0; }
.question-card { background: var(--card); border-radius: var(--radius); padding: 30px; }
.q-number { font-size: 14px; opacity: 0.7; margin-bottom: 10px; }
.q-text { font-size: 20px; margin-bottom: 20px; line-height: 1.6; }
.q-type { font-size: 13px; opacity: 0.6; margin-bottom: 15px; }
.q-options { display: flex; flex-direction: column; gap: 10px; }
.option-item { display: flex; align-items: center; gap: 10px; padding: 12px 16px; border: 2px solid var(--border-color); border-radius: var(--radius); cursor: pointer; transition: var(--transition); }
.option-item:hover { border-color: var(--accent); }
.option-item.selected { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 10%, transparent); }
.option-item input[type="radio"] { display: none; }
.fill-input { width: 100%; padding: 12px 16px; border: 2px solid var(--accent); border-radius: var(--radius); background: var(--card); color: var(--text); font-size: 16px; }
.quiz-header { display: flex; align-items: center; gap: 20px; margin-bottom: 20px; }
.quiz-progress { flex: 1; display: flex; align-items: center; gap: 10px; }
.progress-bar { flex: 1; height: 8px; background: var(--bg); border-radius: 4px; overflow: hidden; }
.progress-fill { height: 100%; background: var(--accent); transition: width 0.3s; width: 0; }
.quiz-timer { font-size: 18px; font-weight: bold; }
.quiz-nav { display: flex; gap: 10px; justify-content: center; margin-top: 20px; }
.quiz-result { text-align: center; padding: 40px 20px; }
.score-circle { width: 150px; height: 150px; border-radius: 50%; background: linear-gradient(135deg, var(--accent), var(--success)); color: white; display: flex; flex-direction: column; align-items: center; justify-content: center; margin: 20px auto; font-size: 48px; font-weight: bold; }
.score-circle span { font-size: 14px; font-weight: normal; }
.wrong-list { text-align: left; margin: 30px auto; max-width: 600px; }
.wrong-item { background: var(--card); padding: 16px; border-radius: 8px; margin-bottom: 10px; border-left: 3px solid var(--danger); }
.wrong { color: var(--danger); font-weight: bold; }
.correct { color: var(--success); font-weight: bold; }

/* Footer */
.site-footer { background: linear-gradient(135deg, var(--primary) 0%, rgba(99,102,241,0.08) 100%); border-top: 1px solid var(--border-color); padding: 18px 20px 14px; margin-top: auto; }
.footer-inner { max-width: 1200px; margin: 0 auto; }
.footer-links { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 16px; margin-bottom: 12px; }
.footer-col h4 { margin-bottom: 8px; color: var(--accent); font-size: 14px; }
.footer-col a { display: block; color: var(--text); opacity: 0.7; padding: 2px 0; font-size: 13px; }
.footer-col a:hover { opacity: 1; color: var(--accent); }
.footer-contact { padding: 1px 0; font-size: 13px; }
.footer-bottom { text-align: center; padding-top: 10px; border-top: 1px solid var(--border-color); font-size: 12px; opacity: 0.5; }

/* Modal */
.modal { display: none; position: fixed; inset: 0; background: rgba(0,0,0,0.7); z-index: 999; align-items: center; justify-content: center; }
.modal.open { display: flex; }
.modal-content { background: var(--card); border-radius: var(--radius); padding: 40px; max-width: 420px; width: 90%; position: relative; box-shadow: var(--shadow); }
.modal-close { position: absolute; top: 15px; right: 20px; font-size: 28px; cursor: pointer; color: var(--text); }
.form-group { margin-bottom: 15px; }
.form-group input, .form-group textarea, .form-group select { width: 100%; padding: 12px 16px; border: 1px solid var(--border-color); border-radius: var(--radius); background: var(--bg); color: var(--text); font-size: 15px; }
.oauth-buttons { display: flex; gap: 10px; margin: 15px 0; }
.btn-oauth { flex: 1; padding: 10px; border: none; border-radius: 8px; cursor: pointer; font-size: 14px; }
.btn-qq { background: #12b7f5; color: white; }
.btn-wechat { background: #07c160; color: white; }
.auth-switch { margin-top: 15px; text-align: center; font-size: 14px; }
.auth-switch a { color: var(--accent); font-weight: bold; }

/* Toast */
.toast { position: fixed; bottom: 80px; left: 50%; transform: translateX(-50%); background: var(--card); color: var(--text); padding: 12px 24px; border-radius: var(--radius); box-shadow: var(--shadow); z-index: 1000; display: none; font-size: 15px; border: 1px solid var(--accent); }
.toast.show { display: block; animation: fadeInUp 0.3s; }
@keyframes fadeInUp { from { opacity: 0; transform: translateX(-50%) translateY(20px); } to { opacity: 1; transform: translateX(-50%) translateY(0); } }

/* Misc */
.loading, .empty-state, .error { text-align: center; padding: 60px 20px; color: var(--text); opacity: 0.7; }
.permission-hint { text-align: center; padding: 20px; margin-top: 20px; background: var(--bg); border-radius: var(--radius); }
.permission-hint a { color: var(--accent); font-weight: bold; }
.ready-submit { text-align: center; padding: 60px 20px; }

/* Responsive */
@media (max-width: 768px) {
    .header-inner { flex-wrap: wrap; }
    .main-nav { display: none; width: 100%; flex-direction: column; padding: 10px 0; }
    .main-nav.open { display: flex; }
    .mobile-menu-btn { display: block; }
    .theme-switcher { display: none; }
}

/* Single price card on homepage */
.cta-single { justify-content: center; }
.price-card-single { max-width: 360px; width: 100%; }
.price-card-single .recommended-badge { background: #ff6b6b; }
.price-card-single .price { font-size: 56px; }
.price-card-single h3 { font-size: 22px; }

/* Partner recommendation cards */
.partners-section { padding: 8px 0 20px; }
.section-subtitle { text-align: center; color: var(--text); opacity: 0.6; margin-top: -8px; margin-bottom: 20px; font-size: 14px; }
.partner-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; }
.partner-card {
    display: flex; flex-wrap: wrap; align-items: center; gap: 4px 10px;
    background: linear-gradient(135deg, var(--card) 0%, color-mix(in srgb, var(--accent) 4%, var(--card)) 100%);
    border-radius: 10px; padding: 8px 14px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
    border: 1px solid rgba(128,128,128,0.08);
    transition: all 0.25s ease;
    text-decoration: none; color: var(--text); border: 1px solid var(--border-color);
    transition: all 0.25s ease; position: relative; overflow: hidden;
}
.partner-card::before {
    content: ''; position: absolute; top: 0; left: 0; right: 0; height: 2px;
    background: linear-gradient(90deg, var(--accent), #6c5ce7); opacity: 0; transition: opacity 0.25s;
}
.partner-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.13), 0 2px 6px rgba(0,0,0,0.08);
    border-color: var(--accent);
    background: linear-gradient(135deg, color-mix(in srgb, var(--accent) 8%, var(--card)) 0%, color-mix(in srgb, var(--accent) 12%, var(--card)) 100%);
    box-shadow: 0 6px 20px rgba(0,0,0,0.10); 
    border-color: var(--accent);
}
.partner-card:hover::before { opacity: 1; }
.partner-icon { font-size: 22px; flex-shrink: 0; width: 28px; text-align: center; line-height: 1; }
.partner-card h4 { font-size: 12px; font-weight: 600; margin: 0; color: var(--text); line-height: 1.3; flex: 1; min-width: 0; }
.partner-card p { display: none; }
.partner-domain { font-size: 10px; color: var(--accent); opacity: 0.8; font-family: monospace; width: 100%; padding-left: 38px; margin-top: 0; }

.partner-card-info { flex: 1; min-width: 0; }
@media (max-width: 1024px) {
    .partner-grid { grid-template-columns: repeat(3, 1fr); gap: 6px; }
}
@media (max-width: 768px) {
    .partner-grid { grid-template-columns: repeat(2, 1fr); gap: 6px; }
}
@media (max-width: 480px) {
    .partner-grid { grid-template-columns: 1fr; gap: 6px; }
}