:root {
  --bg: #f5fbfa;
  --surface: #ffffff;
  --surface-2: #eef8f6;
  --primary: #0f766e;
  --primary-2: #0ea5a4;
  --primary-3: #0c4a6e;
  --accent: #d4a017;
  --text: #0f172a;
  --muted: #64748b;
  --border: rgba(15, 118, 110, 0.12);
  --shadow: 0 18px 50px rgba(15, 23, 42, 0.08);
  --radius: 24px;
  --radius-sm: 16px;
  --radius-xs: 12px;
  --maxw: 1400px;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; font-family: Inter, ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif; background: linear-gradient(180deg,#f8fcfc,#f2f8f7); color: var(--text); }
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
button, input, select, textarea { font: inherit; }
button { cursor: pointer; border: none; }
.hidden { display: none !important; }
.muted { color: var(--muted); }
.badge { display:inline-flex; align-items:center; gap:6px; border-radius:999px; padding:6px 12px; font-size:12px; font-weight:700; }
.badge.free { background:#d7f9e9; color:#0d7a52; }
.badge.paid { background:#fff3cd; color:#8a6410; }
.badge.mentor { background:#ddf4ff; color:#0b5cad; }
.badge.student { background:#ecebff; color:#5842d4; }
.badge.pending { background:#fff1f2; color:#be123c; }
.container { width: min(var(--maxw), calc(100% - 32px)); margin: 0 auto; }
.topbar {
  position: sticky; top: 0; z-index: 50; backdrop-filter: blur(16px);
  background: rgba(255,255,255,0.85); border-bottom: 1px solid rgba(15,118,110,.08);
}
.topbar-inner { display:flex; align-items:center; gap:16px; padding:14px 0; }
.brand { display:flex; align-items:center; gap:12px; min-width: max-content; }
.brand img { width: 48px; height: 48px; }
.brand-title { font-weight: 800; font-size: 20px; line-height: 1; }
.brand-sub { font-size: 12px; color: var(--muted); margin-top: 4px; }
.nav { display:flex; align-items:center; gap:18px; margin-left:24px; }
.nav a { padding:10px 12px; border-radius: 12px; color: var(--muted); font-weight:600; }
.nav a.active, .nav a:hover { color: var(--primary); background: rgba(15,118,110,.08); }
.search-shell { flex: 1; display:flex; justify-content:flex-end; gap:12px; align-items:center; }
.search-box { position:relative; width: min(420px, 100%); }
.search-box input { width:100%; height:48px; border-radius:16px; border:1px solid var(--border); background:var(--surface); padding:0 16px 0 44px; outline:none; }
.search-box svg { position:absolute; left:16px; top:50%; transform:translateY(-50%); width:18px; height:18px; color: var(--muted); }
.header-actions { display:flex; gap:10px; align-items:center; }
.btn {
  display:inline-flex; align-items:center; justify-content:center; gap:10px;
  height:46px; padding:0 18px; border-radius:16px; background:var(--surface);
  border:1px solid var(--border); color:var(--text); font-weight:700; transition: .2s ease;
}
.btn:hover { transform: translateY(-1px); box-shadow: 0 10px 24px rgba(15,118,110,.09); }
.btn.primary { background: linear-gradient(135deg, var(--primary-2), var(--primary)); color:#fff; border-color: transparent; }
.btn.dark { background: linear-gradient(135deg, #0f172a, #0f766e); color:#fff; border-color: transparent; }
.btn.gold { background: linear-gradient(135deg, #eab308, #d4a017); color:#1f2937; border-color: transparent; }
.btn.ghost { background: rgba(15,118,110,.06); color: var(--primary); }
.btn.small { height: 38px; padding: 0 14px; border-radius: 12px; font-size: 14px; }
.auth-grid, .landing-grid { display:grid; grid-template-columns: 1.1fr .9fr; gap:26px; align-items:stretch; padding: 28px 0 40px; }
.hero-card {
  background: radial-gradient(circle at top right, rgba(212,160,23,.18), transparent 20%), linear-gradient(145deg, #083344, #0f766e 58%, #0ea5a4);
  color: #fff; border-radius: 32px; padding: 34px; box-shadow: var(--shadow); position:relative; overflow:hidden;
}
.hero-card::before {
  content:""; position:absolute; inset:auto -80px -80px auto; width:280px; height:280px; border-radius:50%;
  background: rgba(255,255,255,.08);
}
.hero-title { font-size: clamp(28px, 4vw, 52px); line-height:1.08; margin:0 0 12px; max-width: 700px; }
.hero-sub { font-size: 17px; color: rgba(255,255,255,.86); max-width: 640px; line-height:1.7; }
.hero-actions { display:flex; gap:12px; flex-wrap: wrap; margin-top:22px; }
.hero-points { display:grid; grid-template-columns: repeat(4,1fr); gap:12px; margin-top:24px; }
.point-card { background: rgba(255,255,255,.1); border:1px solid rgba(255,255,255,.12); border-radius:20px; padding:16px; }
.point-card strong { display:block; font-size:14px; margin-bottom:6px; }
.panel { background: var(--surface); border:1px solid rgba(15,118,110,.08); border-radius: 28px; box-shadow: var(--shadow); }
.auth-panel { padding: 26px; }
.auth-tabs { display:flex; gap:10px; margin-bottom:18px; }
.auth-tabs button { flex:1; height:46px; border-radius:16px; background:#f1f5f9; color:var(--muted); font-weight:800; }
.auth-tabs button.active { background: linear-gradient(135deg, rgba(14,165,164,.15), rgba(15,118,110,.12)); color:var(--primary); }
.form-grid { display:grid; grid-template-columns: 1fr 1fr; gap:14px; }
.field { display:flex; flex-direction:column; gap:8px; margin-bottom: 14px; }
.field.full { grid-column: 1/-1; }
.field label { font-size: 13px; font-weight: 700; color: #334155; }
.field input, .field textarea, .field select {
  min-height: 48px; border:1px solid var(--border); border-radius: 16px; background: #fff; padding: 12px 14px; outline:none;
}
.field textarea { min-height: 110px; resize: vertical; }
.note { padding: 12px 14px; border-radius: 14px; background: #effcf8; color: #166534; font-size: 14px; }
.stats-row { display:grid; grid-template-columns: repeat(4,1fr); gap:18px; margin-top: 24px; }
.stat-card { padding:18px; border-radius: 22px; background: #fff; border: 1px solid var(--border); }
.stat-card strong { display:block; font-size:32px; color: var(--primary); }
.catalog-section { padding: 12px 0 40px; }
.section-head { display:flex; justify-content:space-between; gap:16px; align-items:end; margin-bottom:16px; }
.section-head h2 { margin:0; font-size: 30px; }
.filters { display:flex; gap:10px; flex-wrap:wrap; }
.pill { border:1px solid var(--border); background:#fff; color:var(--muted); border-radius:999px; height:40px; padding:0 16px; font-weight:700; }
.pill.active { background: rgba(15,118,110,.1); color: var(--primary); }
.class-grid { display:grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.class-card { overflow:hidden; position:relative; }
.class-cover { aspect-ratio: 16/9; background: linear-gradient(135deg,#0f766e,#0c4a6e 60%,#d4a017); position:relative; display:flex; align-items:flex-end; padding:18px; color:#fff; }
.class-cover::after { content:""; position:absolute; inset:0; background:linear-gradient(180deg,transparent,rgba(2,6,23,.58)); }
.class-cover > * { position:relative; z-index:1; }
.class-body { padding:18px; }
.class-title { font-size:20px; font-weight:800; margin: 0 0 8px; }
.class-meta { display:flex; justify-content:space-between; gap:10px; color: var(--muted); font-size: 13px; margin-top:10px; }
.course-price { font-size: 24px; font-weight: 800; color: #b45309; }
.layout-app { display:grid; grid-template-columns: 290px 1fr; min-height: calc(100vh - 80px); }
.sidebar {
  background: linear-gradient(180deg,#083344,#0b4b5e 55%,#0f766e); color:#fff; padding: 22px 18px; position: sticky; top: 78px; height: calc(100vh - 78px); overflow:auto;
}
.sidebar .brand { margin-bottom: 18px; }
.sidebar .brand-title { color:#fff; font-size: 22px; }
.sidebar .brand-sub { color: rgba(255,255,255,.7); }
.side-menu { display:flex; flex-direction:column; gap:8px; margin-top: 20px; }
.side-menu a, .side-menu button {
  display:flex; align-items:center; gap:12px; padding: 14px 16px; border-radius: 18px; color: rgba(255,255,255,.84); background: transparent; border:none; width:100%; text-align:left; font-weight:700;
}
.side-menu a.active, .side-menu a:hover, .side-menu button:hover { background: rgba(255,255,255,.12); color:#fff; }
.side-footer { margin-top: 24px; padding: 18px; border-radius: 22px; background: rgba(255,255,255,.08); border:1px solid rgba(255,255,255,.08); }
.app-content { padding: 24px 24px 100px; }
.app-hero { padding: 26px; display:grid; grid-template-columns: 1.2fr .8fr; gap: 18px; }
.app-hero-banner {
  border-radius: 28px; padding: 30px; color:#fff; min-height: 240px; background: linear-gradient(135deg, rgba(2,44,34,1), rgba(15,118,110,.95));
  position:relative; overflow:hidden;
}
.app-hero-banner::after { content:""; position:absolute; inset:auto -70px -100px auto; width:260px; height:260px; border-radius:50%; background: rgba(255,255,255,.08); }
.app-hero-banner h1 { margin: 0 0 12px; font-size: 40px; }
.app-hero-progress { padding: 24px; border-radius: 28px; background: linear-gradient(180deg,#ffffff,#f4faf9); border:1px solid var(--border); }
.progress-ring { width: 128px; height: 128px; border-radius: 50%; background: conic-gradient(var(--accent) 75%, #dbe7e5 0); padding: 12px; margin: 8px auto 18px; }
.progress-ring .inner { background:#fff; width:100%; height:100%; border-radius:50%; display:grid; place-items:center; font-size: 28px; font-weight: 800; color:var(--primary); }
.cards-two { display:grid; grid-template-columns: 1.3fr .7fr; gap: 18px; }
.video-layout { display:grid; grid-template-columns: 1.25fr .75fr; gap: 18px; }
.video-player-shell { padding: 18px; }
.video-embed { position:relative; width:100%; aspect-ratio: 16 / 9; overflow:hidden; border-radius: 24px; background: #0b1120; }
.video-embed iframe, .video-embed video, .video-embed .drive-frame { position:absolute; inset:0; width:100%; height:100%; border:0; }
.video-header { display:flex; justify-content:space-between; gap:16px; align-items:start; margin: 0 0 16px; }
.video-header h1 { margin:0; font-size: 30px; }
.tabs { display:flex; gap:10px; border-bottom:1px solid rgba(15,118,110,.08); margin-top:20px; }
.tabs button { padding:14px 6px; background:none; color: var(--muted); font-weight:800; border-bottom:3px solid transparent; border-radius:0; }
.tabs button.active { color:var(--primary); border-bottom-color:var(--primary); }
.tab-panel { padding-top:16px; }
.module-list, .payment-box, .profile-box, .chat-box, .admin-panel { padding: 20px; }
.list-clean { display:flex; flex-direction:column; gap:10px; }
.lesson-item, .chat-item, .forum-item, .payment-item, .user-item { border:1px solid var(--border); border-radius: 18px; padding: 14px; background:#fff; }
.lesson-item.active { background: #eefaf8; border-color: rgba(15,118,110,.22); }
.forum-list { display:flex; flex-direction:column; gap:12px; margin-bottom:16px; }
.forum-item { display:flex; gap:12px; }
.avatar { width:44px; height:44px; border-radius:50%; display:grid; place-items:center; background: linear-gradient(135deg,#0ea5a4,#0c4a6e); color:#fff; font-weight:800; flex:0 0 auto; }
.forum-bubble { flex:1; }
.forum-meta { display:flex; gap:8px; align-items:center; flex-wrap:wrap; margin-bottom:6px; }
.forum-content { white-space: pre-wrap; line-height:1.65; color:#334155; }
.reply-box { margin-top:8px; padding-left:12px; border-left:2px solid rgba(15,118,110,.12); }
.sticky-mobile-nav { display:none; position: fixed; left: 12px; right: 12px; bottom: 12px; z-index: 60; background: rgba(255,255,255,.95); backdrop-filter: blur(16px); border-radius: 22px; padding: 10px; border:1px solid rgba(15,118,110,.1); box-shadow: var(--shadow); }
.sticky-mobile-nav a { flex:1; display:flex; flex-direction:column; align-items:center; gap:6px; font-size:12px; color:var(--muted); font-weight:700; padding:8px 6px; border-radius:14px; }
.sticky-mobile-nav a.active { background: rgba(15,118,110,.1); color: var(--primary); }
.empty-state { padding: 34px; text-align:center; color: var(--muted); border: 1px dashed rgba(15,118,110,.2); border-radius: 20px; }
.kv-grid { display:grid; grid-template-columns: repeat(3,1fr); gap:14px; }
.kv { background: #fff; border: 1px solid var(--border); border-radius: 18px; padding: 16px; }
.kv strong { display:block; margin-bottom:6px; color: var(--muted); font-size:13px; }
.copy-row { display:flex; gap:10px; align-items:center; }
.notice { background:#fffbeb; color:#92400e; border:1px solid #fcd34d; border-radius:18px; padding:14px 16px; }
.table-wrap { overflow:auto; border-radius: 20px; border:1px solid rgba(15,118,110,.08); }
table { width:100%; border-collapse: collapse; background:#fff; }
th, td { padding: 14px 16px; text-align:left; border-bottom:1px solid rgba(15,118,110,.08); }
th { font-size: 13px; text-transform: uppercase; letter-spacing: .05em; color: var(--muted); background: #f7fbfa; }
.toast { position: fixed; right: 20px; top: 20px; z-index: 100; padding: 14px 16px; background: #052e2b; color: #fff; border-radius: 16px; box-shadow: var(--shadow); opacity: 0; transform: translateY(-8px); pointer-events: none; transition: .25s ease; }
.toast.show { opacity: 1; transform: translateY(0); }
.modal-backdrop { position: fixed; inset: 0; background: rgba(2,6,23,.42); display:none; align-items:center; justify-content:center; padding:20px; z-index: 70; }
.modal-backdrop.show { display:flex; }
.modal { width:min(820px,100%); max-height:90vh; overflow:auto; background:#fff; border-radius: 30px; padding: 24px; box-shadow: var(--shadow); }
.utility-row { display:flex; gap:10px; flex-wrap:wrap; align-items:center; }
hr.sep { border:none; border-top:1px solid rgba(15,118,110,.08); margin:18px 0; }
@media (max-width: 1180px) {
  .class-grid { grid-template-columns: repeat(3,1fr); }
  .landing-grid, .auth-grid, .app-hero, .cards-two, .video-layout { grid-template-columns: 1fr; }
}
@media (max-width: 980px) {
  .layout-app { grid-template-columns: 1fr; }
  .sidebar { display:none; }
  .nav { display:none; }
  .topbar-inner { flex-wrap: wrap; }
  .search-shell { width:100%; }
  .hero-points, .stats-row, .kv-grid { grid-template-columns: repeat(2,1fr); }
  .class-grid { grid-template-columns: repeat(2,1fr); }
  .sticky-mobile-nav { display:flex; }
  .app-content { padding-bottom: 110px; }
}
@media (max-width: 640px) {
  .container { width: min(var(--maxw), calc(100% - 20px)); }
  .topbar-inner { padding: 12px 0; }
  .brand img { width:42px; height:42px; }
  .brand-title { font-size:18px; }
  .header-actions { width:100%; justify-content:space-between; }
  .search-box { width:100%; }
  .hero-card, .auth-panel, .panel, .app-hero-banner, .app-hero-progress, .video-player-shell { border-radius: 24px; }
  .hero-card { padding:24px; }
  .hero-title { font-size: 33px; }
  .hero-points, .stats-row, .kv-grid, .class-grid, .form-grid { grid-template-columns: 1fr; }
  .section-head { flex-direction:column; align-items:start; }
  .video-header { flex-direction:column; }
  .video-header h1 { font-size:24px; }
  .tabs { overflow:auto; }
  .sticky-mobile-nav { left: 8px; right: 8px; bottom: 8px; }
}