/* course.99dfy.com — one stylesheet, no framework.
   Warm neutral ground, one accent, generous type. The student's screen should
   feel like a place to concentrate, not a dashboard. */

:root {
  --bg:#faf9f7; --panel:#ffffff; --ink:#1c1917; --ink-2:#57534e; --ink-3:#8b8681;
  --line:#e7e5e4; --line-2:#d6d3d1;
  --accent:#1c1917; --accent-ink:#ffffff;
  --good:#15803d; --good-bg:#f0fdf4;
  --warn:#b45309; --warn-bg:#fffbeb;
  --bad:#b91c1c;  --bad-bg:#fef2f2;
  --radius:12px; --radius-lg:16px;
  --shadow:0 1px 2px rgba(28,25,23,.06), 0 4px 16px rgba(28,25,23,.05);
  --sidebar:340px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg:#0f0e0d; --panel:#1a1917; --ink:#f5f5f4; --ink-2:#a8a29e; --ink-3:#78716c;
    --line:#292524; --line-2:#3f3b38;
    --accent:#f5f5f4; --accent-ink:#1c1917;
    --good:#4ade80; --good-bg:#052e16;
    --warn:#fbbf24; --warn-bg:#2a1f05;
    --bad:#f87171;  --bad-bg:#2a0f0f;
    --shadow:0 1px 2px rgba(0,0,0,.4), 0 4px 20px rgba(0,0,0,.3);
  }
}

*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0; background:var(--bg); color:var(--ink);
  font:15px/1.6 -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  -webkit-font-smoothing:antialiased;
}
a{color:inherit}
h1,h2,h3{line-height:1.25; margin:0 0 .5em; letter-spacing:-.01em}
h1{font-size:26px} h2{font-size:19px} h3{font-size:16px}
p{margin:0 0 1em}
small,.small{font-size:13px;color:var(--ink-2)}
.muted{color:var(--ink-3)}
code,kbd{font:12px/1.5 ui-monospace,SFMono-Regular,Menlo,monospace;background:var(--bg);
  border:1px solid var(--line);border-radius:5px;padding:1px 5px}

/* ---------- shell ---------- */
.topbar{
  position:sticky; top:0; z-index:40; display:flex; align-items:center; gap:16px;
  padding:0 20px; height:56px; background:color-mix(in srgb,var(--panel) 88%,transparent);
  backdrop-filter:saturate(1.6) blur(10px); border-bottom:1px solid var(--line);
}
.topbar .brand{font-weight:650;letter-spacing:-.02em;text-decoration:none;font-size:15px}
.topbar nav{margin-left:auto;display:flex;align-items:center;gap:4px}
.topbar nav a{
  text-decoration:none;color:var(--ink-2);padding:7px 12px;border-radius:8px;font-size:14px;
}
.topbar nav a:hover{background:var(--bg);color:var(--ink)}
.topbar nav a.on{color:var(--ink);font-weight:600;background:var(--bg)}
.wrap{max-width:1100px;margin:0 auto;padding:32px 20px 80px}
.wrap.narrow{max-width:660px}

/* ---------- bits ---------- */
.card{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius-lg);
  padding:24px;box-shadow:var(--shadow);margin-bottom:18px}
.card.tight{padding:16px}
.row{display:flex;gap:12px;align-items:center;flex-wrap:wrap}
.row.between{justify-content:space-between}
.grid{display:grid;gap:16px}
.grid.c2{grid-template-columns:repeat(auto-fit,minmax(260px,1fr))}
.grid.c4{grid-template-columns:repeat(auto-fit,minmax(150px,1fr))}
.stack{display:flex;flex-direction:column;gap:10px}

.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  background:var(--accent);color:var(--accent-ink);border:1px solid transparent;
  padding:11px 20px;border-radius:10px;font:inherit;font-weight:600;font-size:14px;
  text-decoration:none;cursor:pointer;transition:opacity .12s,transform .06s;
}
.btn:hover{opacity:.88}
.btn:active{transform:translateY(1px)}
.btn.ghost{background:transparent;color:var(--ink);border-color:var(--line-2)}
.btn.ghost:hover{background:var(--bg);opacity:1}
.btn.danger{background:transparent;color:var(--bad);border-color:var(--line-2)}
.btn.sm{padding:7px 13px;font-size:13px;border-radius:8px}
.btn.block{width:100%}
.btn[disabled]{opacity:.45;pointer-events:none}

label{display:block;font-size:13px;font-weight:600;color:var(--ink-2);margin:0 0 6px}
input[type=text],input[type=email],input[type=password],input[type=url],input[type=number],
select,textarea{
  width:100%;padding:11px 13px;border:1px solid var(--line-2);border-radius:10px;
  background:var(--panel);color:var(--ink);font:inherit;font-size:15px;
}
input:focus,select:focus,textarea:focus{outline:2px solid var(--ink);outline-offset:-1px;border-color:transparent}
textarea{min-height:110px;resize:vertical;line-height:1.6}
.field{margin-bottom:16px}
.check{display:flex;gap:10px;align-items:flex-start;font-size:14px;color:var(--ink);font-weight:400}
.check input{margin-top:3px;width:16px;height:16px;flex:none;accent-color:var(--ink)}

.pill{display:inline-flex;align-items:center;gap:5px;font-size:12px;font-weight:600;
  padding:3px 9px;border-radius:999px;background:var(--bg);border:1px solid var(--line);color:var(--ink-2)}
.pill.good{color:var(--good);background:var(--good-bg);border-color:transparent}
.pill.warn{color:var(--warn);background:var(--warn-bg);border-color:transparent}
.pill.bad{color:var(--bad);background:var(--bad-bg);border-color:transparent}

.note{padding:14px 16px;border-radius:10px;font-size:14px;line-height:1.55;margin-bottom:16px}
.note.good{background:var(--good-bg);color:var(--good)}
.note.warn{background:var(--warn-bg);color:var(--warn)}
.note.bad{background:var(--bad-bg);color:var(--bad)}

table{width:100%;border-collapse:collapse;font-size:14px}
th{text-align:left;font-size:12px;text-transform:uppercase;letter-spacing:.05em;
  color:var(--ink-3);font-weight:600;padding:0 12px 10px;border-bottom:1px solid var(--line)}
td{padding:11px 12px;border-bottom:1px solid var(--line);vertical-align:top}
tr:last-child td{border-bottom:0}
.scroll-x{overflow-x:auto;-webkit-overflow-scrolling:touch}

.stat{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:16px}
.stat .n{font-size:28px;font-weight:680;letter-spacing:-.02em;line-height:1.1}
.stat .k{font-size:12px;color:var(--ink-3);text-transform:uppercase;letter-spacing:.05em;margin-top:6px}

.bar{height:5px;background:var(--line);border-radius:999px;overflow:hidden}
.bar > i{display:block;height:100%;background:var(--ink);border-radius:999px;transition:width .3s}

/* ---------- login ---------- */
.auth{min-height:100dvh;display:grid;place-items:center;padding:24px}
.auth .box{width:100%;max-width:400px}
.auth .box h1{font-size:24px;text-align:center}
.auth .box > p{text-align:center;color:var(--ink-2);margin-bottom:26px}
.auth .card{padding:28px}
.or{display:flex;align-items:center;gap:12px;color:var(--ink-3);font-size:12px;margin:20px 0}
.or::before,.or::after{content:"";flex:1;height:1px;background:var(--line)}

/* ---------- the classroom ---------- */
.class{display:grid;grid-template-columns:1fr var(--sidebar);min-height:calc(100dvh - 56px)}
.stage{padding:0 0 60px;min-width:0}
.player{background:#000;position:relative;aspect-ratio:16/9;width:100%}
.player iframe,.player video{position:absolute;inset:0;width:100%;height:100%;border:0;display:block}
.player .none{position:absolute;inset:0;display:grid;place-items:center;color:#78716c;font-size:14px}
.lesson-body{max-width:760px;margin:0 auto;padding:28px 24px}
.lesson-body h1{font-size:23px;margin-bottom:6px}
.lesson-kicker{font-size:13px;color:var(--ink-3);margin-bottom:20px}
.prose{font-size:16px;line-height:1.7;color:var(--ink-2)}
.prose p{margin:0 0 1.1em}
.lesson-nav{display:flex;gap:10px;justify-content:space-between;margin-top:32px;
  padding-top:22px;border-top:1px solid var(--line)}

.side{border-left:1px solid var(--line);background:var(--panel);
  max-height:calc(100dvh - 56px);overflow-y:auto;position:sticky;top:56px}
.side-head{padding:20px 20px 16px;border-bottom:1px solid var(--line);
  position:sticky;top:0;background:var(--panel);z-index:2}
.side-head .t{font-weight:650;font-size:15px;margin-bottom:12px;letter-spacing:-.01em}
.side-head .pct{font-size:12px;color:var(--ink-3);margin-top:8px}
.mod{padding:16px 20px 4px;font-size:11px;font-weight:700;letter-spacing:.07em;
  text-transform:uppercase;color:var(--ink-3)}
.les{display:flex;gap:11px;align-items:flex-start;padding:10px 20px;text-decoration:none;
  color:var(--ink-2);font-size:14px;line-height:1.45;border-left:2px solid transparent}
.les:hover{background:var(--bg);color:var(--ink)}
.les.on{background:var(--bg);color:var(--ink);font-weight:600;border-left-color:var(--ink)}
.les .tick{flex:none;width:17px;height:17px;border-radius:50%;border:1.5px solid var(--line-2);
  margin-top:2px;display:grid;place-items:center;font-size:10px;color:transparent}
.les.done .tick{background:var(--good);border-color:var(--good);color:#fff}
.les.part .tick{border-color:var(--ink-3);border-style:dashed}

.res{display:flex;align-items:center;gap:10px;padding:12px 14px;border:1px solid var(--line);
  border-radius:10px;text-decoration:none;color:var(--ink);font-size:14px;font-weight:500;
  background:var(--panel);margin-bottom:8px}
.res:hover{border-color:var(--line-2);background:var(--bg)}

@media (max-width:900px){
  .class{grid-template-columns:1fr}
  .side{border-left:0;border-top:1px solid var(--line);position:static;max-height:none}
  :root{--sidebar:100%}
}

/* ---------- evidence pack (screen + print) ---------- */
.ev{max-width:820px;margin:0 auto;padding:36px 28px 80px;background:var(--panel)}
.ev h1{font-size:22px}
.ev h2{font-size:15px;text-transform:uppercase;letter-spacing:.06em;color:var(--ink-3);
  margin:34px 0 12px;padding-bottom:8px;border-bottom:1px solid var(--line)}
.ev .kv{display:grid;grid-template-columns:190px 1fr;gap:6px 16px;font-size:13.5px}
.ev .kv dt{color:var(--ink-3)}
.ev .kv dd{margin:0;word-break:break-word}
.ev .facts li{margin-bottom:8px;line-height:1.55}
.ev table{font-size:12.5px}
.ev td,.ev th{padding:7px 10px}
.ev .mono{font:11.5px/1.5 ui-monospace,SFMono-Regular,Menlo,monospace}
@media print{
  .no-print{display:none!important}
  body{background:#fff;color:#000}
  .ev{max-width:none;padding:0}
  .ev h2{break-after:avoid}
  table{break-inside:auto} tr{break-inside:avoid}
  a{text-decoration:none;color:#000}
}