:root{
  --navy:#071b5b;--blue:#123c8d;--orange:#f97316;--bg:#f5f7fb;--card:#fff;
  --text:#1f2937;--muted:#667085;--border:#e5eaf2;--sidebar:#071b5b;
}
html[data-theme="dark"]{
  --bg:#0d1423;--card:#141d2f;--text:#edf2f7;--muted:#9aa8bc;--border:#26334a;--sidebar:#081127;
}
*{box-sizing:border-box}body{margin:0;font-family:Inter,Arial,sans-serif;background:var(--bg);color:var(--text)}
a{text-decoration:none;color:inherit}.muted{color:var(--muted)}
.app-shell{min-height:100vh;display:grid;grid-template-columns:240px 1fr}
.sidebar{background:var(--sidebar);color:#fff;padding:24px 16px}.logo{font-size:28px;font-weight:800;margin:0 10px 28px}
.sidebar nav{display:grid;gap:6px}.sidebar nav a{padding:11px 12px;border-radius:8px;color:#dce6ff}
.sidebar nav a:hover,.sidebar nav a.active{background:#17367f;color:#fff}
.main{padding:26px}.topbar{display:flex;justify-content:space-between;gap:16px;align-items:center;margin-bottom:24px}
.topbar h1{margin:0;font-size:28px}.top-actions{display:flex;gap:10px;align-items:center}
select,input,button{font:inherit}select,input{background:var(--card);color:var(--text);border:1px solid var(--border);padding:10px 12px;border-radius:8px}
.btn{display:inline-block;background:#eef2f8;color:var(--text);padding:10px 14px;border-radius:8px;border:0;cursor:pointer}
.btn.primary,button.btn.primary{background:var(--navy);color:#fff}
.stats-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;margin-bottom:22px}
.stat-card,.panel,.video-card{background:var(--card);border:1px solid var(--border);border-radius:14px;padding:20px;box-shadow:0 8px 28px rgba(0,0,0,.035)}
.stat-num{font-size:30px;font-weight:800;color:#2d63e2}.panel{margin-bottom:20px}.panel h2{margin-top:0}
.notice{background:#eef5ff;border:1px solid #cfe0ff;padding:12px 14px;border-radius:10px;color:#21447c}
html[data-theme="dark"] .notice{background:#14233d;border-color:#263d65;color:#d7e5ff}
.auth-page{min-height:100vh;display:grid;place-items:center;padding:20px}.login-card{width:min(420px,100%);background:var(--card);border:1px solid var(--border);border-radius:18px;padding:30px;box-shadow:0 20px 50px rgba(0,0,0,.08)}
.login-card .brand{font-weight:900;font-size:28px;color:var(--navy)}html[data-theme="dark"] .login-card .brand{color:#8fb1ff}
.login-card h1{margin-bottom:6px}.login-card label{display:block;font-weight:700;margin:14px 0 6px}.login-card input{width:100%}.login-card button{width:100%;margin-top:18px;padding:12px;background:var(--navy);color:white;border:0;border-radius:8px;font-weight:700}
.alert{background:#fff0f0;color:#8a1f1f;padding:10px;border-radius:8px;margin-top:12px}
.simple-page{max-width:1180px;margin:0 auto;padding:28px}.back{color:#2d63e2;font-weight:700}.video-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.video-badge{display:inline-block;background:#eef4ff;color:#2450a4;border-radius:99px;padding:6px 10px;font-size:12px;font-weight:700}
.form-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:12px}.form-grid .btn{justify-self:start}
.table-wrap{overflow:auto}table{width:100%;border-collapse:collapse}th,td{text-align:left;padding:11px;border-bottom:1px solid var(--border)}th{color:var(--muted);font-size:13px}
@media(max-width:900px){.app-shell{grid-template-columns:1fr}.sidebar{position:relative}.stats-grid{grid-template-columns:repeat(2,1fr)}.video-grid{grid-template-columns:1fr 1fr}}
@media(max-width:600px){.main,.simple-page{padding:16px}.topbar{align-items:flex-start;flex-direction:column}.stats-grid,.video-grid,.form-grid{grid-template-columns:1fr}.top-actions{width:100%;justify-content:space-between}}