:root{
  color-scheme:dark;
  --bg:#0E0E10;--bg-alt:#151518;--card:#1B1B1F;--ink:#F4F4F5;--muted:#A9A9B0;--line:#2C2C31;
  --accent:#FF7A1A;--accent-strong:#FF9A4D;--accent-soft:#2B1709;--ok:#3DDC84;--err:#FF6B6B;
}
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:"Prompt",system-ui,sans-serif;background:var(--bg);color:var(--ink);line-height:1.6;-webkit-font-smoothing:antialiased}
a{color:inherit}
.wrap{max-width:960px;margin:0 auto;padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px))}
header{border-bottom:1px solid var(--line);background:var(--bg)}
header .wrap{display:flex;align-items:center;justify-content:space-between;gap:12px;height:60px}
.logo{font-weight:800;font-size:18px;text-decoration:none;white-space:nowrap}.logo span{color:var(--accent)}
.who{font-size:13px;color:var(--muted);display:flex;gap:10px;align-items:center;min-width:0}
.who span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
main{padding-block:28px 60px}
h1{font-size:clamp(24px,5vw,34px);line-height:1.25;font-weight:800;text-wrap:balance}
h2{font-size:20px;font-weight:700;margin:24px 0 10px}
.muted{color:var(--muted)}.small{font-size:13px}
.box{background:var(--card);border:1px solid var(--line);border-radius:18px;padding:20px;max-width:440px}
label{display:block;font-size:14px;color:var(--muted);margin:14px 0 6px}
input{width:100%;font:inherit;font-size:17px;background:var(--bg-alt);color:var(--ink);border:1.5px solid var(--line);border-radius:12px;padding:12px 14px}
input:focus{outline:none;border-color:var(--accent)}
input.code{letter-spacing:8px;font-size:24px;text-align:center}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;font:inherit;font-weight:600;font-size:16px;text-decoration:none;border:0;border-radius:99px;padding:12px 22px;cursor:pointer}
.btn:disabled{opacity:.5;cursor:default}
.btn-o{background:var(--accent);color:#111}.btn-o:hover{background:var(--accent-strong)}
.btn-g{background:transparent;color:var(--ink);border:1.5px solid var(--line)}
.btn-sm{font-size:14px;padding:7px 14px}
.full{width:100%;margin-top:16px}
.msg{margin-top:12px;font-size:14px}.msg.err{color:var(--err)}.msg.ok{color:var(--ok)}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.grid{display:grid;gap:12px;grid-template-columns:1fr}
@media(min-width:640px){.grid{grid-template-columns:repeat(2,1fr)}}
.tile{display:block;text-decoration:none;background:var(--card);border:1px solid var(--line);border-radius:16px;padding:16px}
.tile:hover{border-color:var(--accent)}
.tile b{display:block;font-size:17px}.tile small{color:var(--muted)}
.dev{list-style:none;display:grid;gap:8px;margin-top:8px}
.dev li{background:var(--bg-alt);border-radius:12px;padding:10px 12px;font-size:14px}
/* course player */
.player{display:grid;gap:18px}
@media(min-width:900px){.player{grid-template-columns:minmax(0,1fr) 320px;align-items:start}}
.player>div{min-width:0}
.video{position:relative;aspect-ratio:16/9;background:#000;border-radius:14px;overflow:hidden}
.video iframe{position:absolute;inset:0;width:100%;height:100%;border:0}
.wm{position:absolute;right:10px;top:10px;font-size:11px;color:rgba(255,255,255,.35);pointer-events:none;user-select:none}
.lessons{background:var(--card);border:1px solid var(--line);border-radius:16px;max-height:70vh;overflow:auto}
.lessons h3{font-size:14px;padding:12px 14px 6px;color:var(--accent)}
.lessons button{display:flex;gap:10px;width:100%;text-align:left;font:inherit;font-size:14px;color:var(--ink);background:none;border:0;border-top:1px solid var(--line);padding:10px 14px;cursor:pointer}
.lessons button.on{background:var(--accent-soft)}
.lessons button small{color:var(--muted);margin-left:auto;flex:none}
.lessons .n{flex:none;color:var(--muted);min-width:22px}
.note{background:var(--accent-soft);border-radius:12px;padding:10px 12px;font-size:14px;margin-top:12px}
/* ebook */
.pages{display:grid;gap:12px;max-width:760px;margin:0 auto}
.pg{position:relative;background:#fff;border-radius:6px;overflow:hidden;min-height:200px}
.pg img{display:block;width:100%;height:auto;user-select:none;-webkit-user-drag:none;pointer-events:none}
.pg .mark{position:absolute;inset:0;pointer-events:none;display:grid;place-items:center;overflow:hidden}
.pg .mark span{transform:rotate(-30deg);font-size:clamp(14px,3vw,22px);font-weight:700;color:rgba(255,122,26,.18);white-space:nowrap;line-height:3.2;text-align:center}
.pg .foot{position:absolute;left:0;right:0;bottom:6px;text-align:center;font-size:11px;color:rgba(0,0,0,.45);pointer-events:none}
table{border-collapse:collapse;width:100%;font-size:14px}
td,th{border-top:1px solid var(--line);padding:8px;text-align:left}
.scroll{overflow-x:auto}
textarea{width:100%;min-height:120px;font:inherit;background:var(--bg-alt);color:var(--ink);border:1.5px solid var(--line);border-radius:12px;padding:10px}
.checks{display:grid;gap:6px;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));margin-top:6px}
.checks label{display:flex;gap:8px;align-items:center;margin:0;color:var(--ink)}
.checks input{width:auto}
[hidden]{display:none!important}