:root{--bg:#f5f7fb;--card:#fff;--text:#0f172a;--muted:#64748b;--primary:#2563eb;--primary2:#1d4ed8;--success:#16a34a;--danger:#dc2626;--warning:#f59e0b;--border:#e2e8f0;--dark:#111827;--shadow:0 18px 45px rgba(15,23,42,.08);--radius:22px}
*{box-sizing:border-box}body{margin:0;font-family:Inter,system-ui,-apple-system,Segoe UI,Arial,sans-serif;background:linear-gradient(135deg,#eef4ff,#f8fafc);color:var(--text);min-height:100vh}.topbar{position:sticky;top:0;z-index:20;display:flex;align-items:center;justify-content:space-between;gap:16px;padding:12px 5vw;background:rgba(255,255,255,.9);backdrop-filter:blur(12px);border-bottom:1px solid var(--border)}.brand{display:flex;align-items:center;gap:10px;color:var(--text);font-weight:800;text-decoration:none}.brand-icon{background:linear-gradient(135deg,var(--primary),#7c3aed);color:#fff;padding:9px 10px;border-radius:14px;font-size:13px;letter-spacing:.5px}.nav{display:flex;align-items:center;gap:10px}.nav a{color:var(--muted);text-decoration:none;font-weight:700;padding:9px 12px;border-radius:12px}.nav a:hover{background:#eff6ff;color:var(--primary)}.menu-btn{display:none;border:0;background:var(--primary);color:#fff;border-radius:12px;padding:9px 12px;font-size:18px}.container{width:min(1180px,92vw);margin:28px auto}.footer{text-align:center;color:var(--muted);font-size:13px;padding:32px}.hero{display:grid;grid-template-columns:1.2fr .8fr;gap:22px;align-items:center}.card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);padding:24px}.card.compact{padding:16px}.title{font-size:clamp(26px,4vw,48px);line-height:1.05;margin:0 0 12px}.subtitle{color:var(--muted);font-size:16px;line-height:1.7}.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.grid.two{grid-template-columns:repeat(2,1fr)}.grid.four{grid-template-columns:repeat(4,1fr)}.stat{padding:20px;border-radius:20px;background:#fff;border:1px solid var(--border)}.stat strong{font-size:30px;display:block}.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;border:0;border-radius:14px;background:var(--primary);color:#fff;text-decoration:none;font-weight:800;padding:12px 16px;cursor:pointer;min-height:44px}.btn:hover{background:var(--primary2)}.btn.secondary{background:#e2e8f0;color:#0f172a}.btn.success{background:var(--success)}.btn.danger{background:var(--danger)}.btn.warning{background:var(--warning);color:#111827}.btn.block{width:100%}input,select,textarea{width:100%;border:1px solid var(--border);border-radius:14px;padding:12px 14px;font:inherit;background:#fff;color:var(--text);min-height:44px}label{font-weight:800;font-size:14px;display:block;margin:12px 0 7px}.form-row{display:grid;grid-template-columns:repeat(2,1fr);gap:14px}.alert{padding:14px 16px;border-radius:16px;margin:14px 0;font-weight:700}.alert.danger{background:#fee2e2;color:#991b1b}.alert.success{background:#dcfce7;color:#166534}.alert.info{background:#dbeafe;color:#1e40af}.table-wrap{overflow:auto;border-radius:18px;border:1px solid var(--border)}table{width:100%;border-collapse:collapse;background:#fff;min-width:720px}th,td{text-align:left;padding:13px 14px;border-bottom:1px solid var(--border);vertical-align:top}th{background:#f8fafc;font-size:13px;color:#475569;text-transform:uppercase;letter-spacing:.04em}.pill{display:inline-flex;padding:7px 10px;border-radius:999px;font-size:12px;font-weight:900;background:#e0f2fe;color:#0369a1}.progress{height:12px;background:#e2e8f0;border-radius:999px;overflow:hidden}.progress span{display:block;height:100%;background:linear-gradient(90deg,var(--primary),#22c55e);border-radius:999px}.chapter{display:grid;grid-template-columns:1fr auto;gap:16px;align-items:center}.video-list{display:grid;gap:12px}.video-item{display:flex;align-items:center;justify-content:space-between;gap:14px;padding:14px;border:1px solid var(--border);border-radius:18px;background:#fff}.video-meta{display:flex;flex-direction:column;gap:4px}.locked{opacity:.55}.youtube-box{position:relative;width:100%;aspect-ratio:16/9;background:#111827;border-radius:22px;overflow:hidden;box-shadow:var(--shadow)}.youtube-box iframe{position:absolute;inset:0;width:100%;height:100%;border:0}.code-layout{display:grid;grid-template-columns:1fr 1fr;gap:16px}.editor-pane textarea{min-height:520px;font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;background:#0b1020;color:#dbeafe;border:0;border-radius:18px;tab-size:2}.preview{width:100%;height:520px;border:1px solid var(--border);border-radius:18px;background:white}.certificate{max-width:900px;margin:auto;text-align:center;padding:50px;border:12px solid #d4af37;background:#fff;border-radius:16px}.certificate h1{font-size:48px;margin:8px 0}.small{font-size:13px;color:var(--muted)}.actions{display:flex;flex-wrap:wrap;gap:10px;margin-top:14px}.login-wrap{min-height:calc(100vh - 160px);display:grid;place-items:center}.login-card{width:min(440px,100%)}
@media(max-width:850px){.hero,.grid,.grid.two,.grid.four,.code-layout{grid-template-columns:1fr}.menu-btn{display:block}.nav{position:absolute;display:none;left:4vw;right:4vw;top:64px;flex-direction:column;align-items:stretch;background:white;border:1px solid var(--border);border-radius:18px;padding:12px;box-shadow:var(--shadow)}.nav-open .nav{display:flex}.container{width:94vw;margin:18px auto}.card{padding:18px}.video-item,.chapter{grid-template-columns:1fr;align-items:stretch}.actions .btn{width:100%}.certificate{padding:24px;border-width:8px}.certificate h1{font-size:32px}.form-row{grid-template-columns:1fr}}
@media(max-width:420px){.topbar{padding:10px 3vw}.brand span:last-child{font-size:14px}.title{font-size:28px}.card{padding:15px;border-radius:18px}.stat strong{font-size:24px}.btn,input,select,textarea{font-size:14px}.preview,.editor-pane textarea{height:420px}.youtube-box{border-radius:16px}}
.compact-actions{margin-top:0}.compact-actions .btn{padding:9px 12px;min-height:38px;font-size:13px}.compact-actions form{margin:0}
@media(max-width:850px){.compact-actions .btn{width:auto}}