:root{
  --bg:#07111f;--bg2:#0b1728;--panel:rgba(15,28,46,.78);--panel-solid:#101d30;
  --line:rgba(255,255,255,.09);--line2:rgba(255,255,255,.14);--text:#eef5ff;--muted:#91a1b6;
  --accent:#66e3bd;--accent2:#6ba7ff;--danger:#ff7187;--gold:#f5c86a;
  --shadow:0 28px 80px rgba(0,0,0,.38);--radius:24px;--sans:"DM Sans",system-ui,sans-serif;--display:"Manrope",system-ui,sans-serif
}
*{box-sizing:border-box;-webkit-tap-highlight-color:transparent}html,body{margin:0;min-height:100%;font-family:var(--sans);background:var(--bg);color:var(--text)}
body{overflow-x:hidden;background:radial-gradient(900px 550px at 0% 0%,rgba(68,125,255,.13),transparent 62%),radial-gradient(900px 600px at 100% 5%,rgba(71,231,185,.10),transparent 60%),linear-gradient(145deg,#06101d,#091727 55%,#07111f)}
body.light{--bg:#f3f7fb;--bg2:#fff;--panel:rgba(255,255,255,.82);--panel-solid:#fff;--line:rgba(10,28,52,.09);--line2:rgba(10,28,52,.15);--text:#102039;--muted:#66778e;--shadow:0 25px 65px rgba(36,69,105,.13)}
button,input,textarea{font:inherit}button{cursor:pointer}.hidden{display:none!important}
.ambient{position:fixed;width:420px;height:420px;border-radius:50%;filter:blur(90px);opacity:.11;pointer-events:none}.ambient-a{background:#36d8b0;right:-180px;top:45%}.ambient-b{background:#4d8dff;left:-220px;bottom:-180px}
.app-shell{max-width:1280px;margin:auto;padding:26px 28px 80px;position:relative;z-index:1}.topbar{height:66px;display:flex;align-items:center;justify-content:space-between;gap:18px;margin-bottom:58px}
.brand{display:flex;align-items:center;gap:12px;background:none;border:0;color:var(--text);padding:0;text-align:left}.brand strong{font:800 17px var(--display);letter-spacing:-.3px;display:block}.brand small{display:block;color:var(--muted);font-size:8px;letter-spacing:2px;margin-top:3px}
.brand-mark{width:39px;height:39px;border:1px solid var(--line2);background:linear-gradient(145deg,rgba(102,227,189,.2),rgba(107,167,255,.12));border-radius:13px;display:flex;align-items:end;justify-content:center;gap:3px;padding:9px;box-shadow:0 10px 30px rgba(0,0,0,.18)}.brand-mark span{width:4px;border-radius:4px;background:var(--accent)}.brand-mark span:nth-child(1){height:9px}.brand-mark span:nth-child(2){height:16px;background:var(--accent2)}.brand-mark span:nth-child(3){height:12px;background:var(--gold)}
.top-actions{display:flex;align-items:center;gap:9px}.sync-pill{font-size:11px;color:var(--muted);border:1px solid var(--line);background:rgba(255,255,255,.035);padding:9px 12px;border-radius:999px;display:flex;gap:7px;align-items:center}.sync-pill i{width:7px;height:7px;border-radius:50%;background:var(--accent);box-shadow:0 0 0 4px rgba(102,227,189,.1)}
.primary-btn,.secondary-btn,.danger-btn,.icon-btn{border:1px solid transparent;border-radius:13px;padding:11px 16px;font-weight:700;font-size:13px;transition:.18s ease;display:inline-flex;align-items:center;gap:8px;justify-content:center}.primary-btn{background:linear-gradient(135deg,#74e9c5,#55cfae);color:#062018;box-shadow:0 12px 30px rgba(77,215,177,.18)}.primary-btn:hover{transform:translateY(-1px);box-shadow:0 15px 35px rgba(77,215,177,.27)}.secondary-btn,.icon-btn{color:var(--text);background:rgba(255,255,255,.045);border-color:var(--line)}.secondary-btn:hover,.icon-btn:hover{background:rgba(255,255,255,.08);border-color:var(--line2)}.danger-btn{background:transparent;color:var(--danger);border-color:rgba(255,113,135,.2)}.danger-btn:hover{background:rgba(255,113,135,.08)}.icon-btn{width:42px;height:42px;padding:0;font-size:17px}
.hero{display:flex;justify-content:space-between;gap:35px;align-items:end;margin-bottom:35px}.eyebrow{display:block;color:var(--accent);font-size:9px;letter-spacing:2px;font-weight:800;margin-bottom:9px}.hero h1{font:800 clamp(38px,6vw,66px)/1.03 var(--display);letter-spacing:-2.7px;margin:0;max-width:720px}.hero h1 em{font-style:normal;background:linear-gradient(100deg,var(--accent),#9be9ff);-webkit-background-clip:text;background-clip:text;color:transparent}.hero p{color:var(--muted);font-size:15px;margin:17px 0 0;max-width:570px;line-height:1.7}.hero-stats{display:flex;gap:28px;padding-bottom:5px}.hero-stats div{min-width:78px}.hero-stats strong{display:block;font:800 25px var(--display);letter-spacing:-1px}.hero-stats span{font-size:10px;color:var(--muted);text-transform:uppercase;letter-spacing:1.1px}
.toolbar{display:flex;gap:14px;align-items:center;justify-content:space-between;margin-bottom:19px}.search{height:48px;max-width:600px;flex:1;display:flex;align-items:center;gap:10px;border:1px solid var(--line);background:rgba(255,255,255,.045);border-radius:14px;padding:0 13px;color:var(--muted)}.search span{font-size:23px;line-height:1}.search input{background:none;border:0;outline:0;color:var(--text);width:100%;font-size:13px}.search kbd{font-size:9px;border:1px solid var(--line2);padding:4px 7px;border-radius:6px;color:var(--muted);white-space:nowrap}.view-label{font-size:11px;color:var(--muted)}
.subject-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(245px,1fr));gap:15px}.subject-card{position:relative;min-height:185px;padding:23px;border:1px solid var(--line);border-radius:21px;background:linear-gradient(145deg,rgba(255,255,255,.075),rgba(255,255,255,.025));overflow:hidden;cursor:pointer;transition:.22s ease;display:flex;flex-direction:column;justify-content:space-between}.subject-card:before{content:"";position:absolute;width:150px;height:150px;border-radius:50%;background:var(--card-glow,rgba(102,227,189,.12));filter:blur(35px);right:-65px;top:-70px}.subject-card:hover{transform:translateY(-5px);border-color:rgba(102,227,189,.3);box-shadow:0 24px 55px rgba(0,0,0,.24)}.card-icon{width:40px;height:40px;border-radius:13px;background:rgba(102,227,189,.1);border:1px solid rgba(102,227,189,.16);display:grid;place-items:center;color:var(--accent);font-weight:800}.subject-card h3{font:700 20px/1.22 var(--display);margin:20px 0 8px;letter-spacing:-.6px;position:relative}.card-meta{display:flex;align-items:center;justify-content:space-between;color:var(--muted);font-size:11px;position:relative}.count{padding:5px 9px;border-radius:999px;background:rgba(255,255,255,.055);border:1px solid var(--line)}.open-arrow{color:var(--accent);font-size:18px}.add-card{border:1px dashed rgba(102,227,189,.3);background:rgba(102,227,189,.025);align-items:center;justify-content:center;text-align:center}.add-card .plus{font-size:34px;color:var(--accent);font-weight:300}.add-card h3{margin:8px 0 3px;font-size:16px}.add-card p{margin:0;color:var(--muted);font-size:11px}
.crumb{display:flex;align-items:center;gap:12px;margin-bottom:28px;color:var(--muted);font-size:11px;min-width:0}.crumb>span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.back-btn{border:0;background:none;color:var(--muted);padding:7px 0;font-weight:700;font-size:12px}.back-btn:hover{color:var(--text)}
.detail-head{display:flex;justify-content:space-between;align-items:end;gap:25px;margin-bottom:28px}.detail-head h2{font:800 clamp(32px,5vw,52px)/1.06 var(--display);letter-spacing:-2px;margin:0}.detail-head p{color:var(--muted);font-size:12px;margin:10px 0 0}.head-actions{display:flex;gap:8px;flex-wrap:wrap}
.chapter-grid .subject-card{min-height:165px}.class-list{display:flex;flex-direction:column;gap:10px;margin-bottom:16px}.class-row{display:grid;grid-template-columns:42px 88px minmax(0,1fr) 40px 34px;gap:13px;align-items:center;padding:10px;border:1px solid var(--line);background:rgba(255,255,255,.038);border-radius:17px;cursor:pointer;transition:.18s}.class-row:hover{background:rgba(255,255,255,.065);border-color:rgba(107,167,255,.25);transform:translateX(2px)}.class-num{font:700 11px var(--sans);color:var(--accent);text-align:center;background:rgba(102,227,189,.08);border:1px solid rgba(102,227,189,.12);padding:8px 4px;border-radius:10px}.class-thumb{width:88px;height:54px;border-radius:10px;object-fit:cover;background:#030811}.class-info{min-width:0}.class-title{font-weight:700;font-size:13px;margin:0 0 4px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.class-url{color:var(--muted);font-size:10px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.play{width:35px;height:35px;border-radius:50%;background:rgba(102,227,189,.11);color:var(--accent);display:grid;place-items:center}.class-del{border:0;background:none;color:var(--muted);font-size:19px}.class-del:hover{color:var(--danger)}.add-row{width:100%;border:1px dashed rgba(102,227,189,.28);background:rgba(102,227,189,.025);border-radius:17px;padding:17px;display:flex;align-items:center;gap:13px;color:var(--text);text-align:left}.add-row>span{font-size:25px;color:var(--accent)}.add-row strong{display:block;font-size:13px}.add-row small{display:block;color:var(--muted);font-size:10px;margin-top:3px}.add-row>b{margin-left:auto;color:var(--accent);font-size:19px}
.video-card{max-width:1000px;margin:0 auto;border:1px solid var(--line);border-radius:26px;background:rgba(255,255,255,.045);box-shadow:var(--shadow);overflow:hidden}.video-head{display:flex;align-items:center;gap:16px;padding:22px 24px}.video-head h2{font:800 23px var(--display);margin:0;letter-spacing:-.7px}.video-number{width:46px;height:46px;border-radius:14px;display:grid;place-items:center;background:linear-gradient(145deg,rgba(102,227,189,.14),rgba(107,167,255,.1));color:var(--accent);font:800 12px var(--sans)}.player-wrap{padding:0 18px}.player{position:relative;aspect-ratio:16/9;background:#02060c;border-radius:18px;overflow:hidden}.player iframe{width:100%;height:100%;border:0}.video-meta{padding:13px 22px 19px;display:flex;gap:12px;align-items:center;font-size:9px;color:var(--muted);letter-spacing:1.5px}.video-meta a{font-size:10px;color:var(--muted);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.video-meta a:hover{color:var(--accent)}
.note-block{border-top:1px solid var(--line);padding:24px}.note-heading{font:700 17px var(--display);margin:0 0 14px}.note-upload-tile{border:1px dashed rgba(102,227,189,.25);border-radius:16px;padding:25px;text-align:center;display:block;background:rgba(102,227,189,.025);cursor:pointer}.note-upload-tile .plus{font-size:28px;color:var(--accent)}.note-upload-tile .label{display:block;font-weight:700;font-size:12px}.note-hint{display:block;color:var(--muted);font-size:10px;margin-top:6px}.note-card{display:flex;align-items:center;gap:13px;border:1px solid var(--line);padding:13px;border-radius:15px;background:rgba(255,255,255,.035)}.note-card-icon{width:40px;height:40px;border-radius:11px;display:grid;place-items:center;background:rgba(107,167,255,.1);font-size:19px}.note-card-info{min-width:0;flex:1}.note-card-name{margin:0 0 4px;font-weight:700;font-size:12px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.note-card-meta{margin:0;color:var(--muted);font-size:9px}.note-card-actions{display:flex;gap:6px;flex-wrap:wrap}.note-btn{font-size:10px;padding:7px 10px}.note-preview{margin-top:13px;border-radius:15px;overflow:hidden}.note-preview img{max-height:560px;width:100%;object-fit:contain;background:#030811}.note-preview-pdf embed{width:100%;height:650px;background:#fff}.note-preview-text{padding:16px;background:rgba(255,255,255,.035);color:var(--muted);font-size:11px;line-height:1.7}.note-error,.error{color:var(--danger);font-size:11px;margin-top:9px;display:none}.tip{font-size:10px;color:var(--muted);padding:10px 12px;border-radius:10px;background:rgba(102,227,189,.05);margin-top:10px}
.scrim{position:fixed;inset:0;z-index:50;background:rgba(1,6,12,.76);backdrop-filter:blur(12px);display:flex;align-items:center;justify-content:center;padding:20px}.modal{position:relative;width:min(450px,100%);border:1px solid var(--line2);border-radius:24px;background:var(--panel-solid);padding:28px;box-shadow:var(--shadow)}.modal.wide{width:min(620px,100%)}.modal-x{position:absolute;right:18px;top:16px;border:0;background:none;color:var(--muted);font-size:25px}.modal h3{font:800 25px var(--display);margin:0 0 6px;letter-spacing:-1px}.modal>p{margin:0 0 24px;color:var(--muted);font-size:12px;line-height:1.6}.modal label{display:block;font-size:10px;text-transform:uppercase;letter-spacing:1px;color:var(--muted);font-weight:800}.modal input,.modal textarea{display:block;width:100%;margin-top:8px;border:1px solid var(--line2);background:rgba(255,255,255,.045);color:var(--text);border-radius:13px;padding:13px 14px;outline:none;font-size:13px}.modal textarea{min-height:190px;resize:vertical;font-size:11px;line-height:1.65}.modal input:focus,.modal textarea:focus{border-color:rgba(102,227,189,.5);box-shadow:0 0 0 3px rgba(102,227,189,.06)}.modal-actions{display:flex;justify-content:flex-end;gap:8px;margin-top:20px}
.toast{position:fixed;z-index:100;bottom:25px;left:50%;transform:translate(-50%,20px);opacity:0;pointer-events:none;background:#f1f7ff;color:#0a1625;border-radius:999px;padding:11px 17px;font-size:12px;font-weight:700;box-shadow:0 20px 50px rgba(0,0,0,.3);transition:.22s}.toast.show{opacity:1;transform:translate(-50%,0)}.toast.err{background:#ffdbe1;color:#681522}
.empty{grid-column:1/-1;padding:65px 20px;text-align:center;border:1px dashed var(--line2);border-radius:20px;color:var(--muted)}.empty strong{display:block;color:var(--text);font:700 18px var(--display);margin-bottom:6px}.empty p{font-size:11px;margin:0}
@media(max-width:760px){.app-shell{padding:18px 15px 60px}.topbar{margin-bottom:40px}.sync-pill{display:none}.primary-btn{padding:10px 12px}.hero{display:block}.hero h1{letter-spacing:-1.8px}.hero-stats{margin-top:25px;gap:24px}.toolbar{display:block}.view-label{margin-top:8px}.subject-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}.subject-card{min-height:165px;padding:17px;border-radius:17px}.subject-card h3{font-size:16px}.detail-head{align-items:start;display:block}.head-actions{margin-top:17px}.class-row{grid-template-columns:35px 62px minmax(0,1fr) 32px 24px;gap:8px}.class-thumb{width:62px;height:42px}.class-title{font-size:11px}.class-url{font-size:8px}.class-del{font-size:16px}.video-head{padding:17px}.player-wrap{padding:0 9px}.video-card{border-radius:19px}.note-card{align-items:flex-start}.note-card-actions{width:100%}.note-card{flex-wrap:wrap}.note-card-info{max-width:calc(100% - 55px)}.note-card-actions{padding-left:53px}.video-meta{padding-left:13px}.crumb{margin-bottom:20px}}
@media(max-width:420px){.subject-grid{grid-template-columns:1fr}.brand small{display:none}.top-actions{gap:5px}.hero h1{font-size:40px}.class-row{grid-template-columns:31px minmax(0,1fr) 30px 20px}.class-thumb{display:none}}