/* Achilles Gambit prototype — gold/navy, mobile-first, thumb-zone.
   Ported structure from Exam Prep Mode: card patterns, streak row,
   briefing card, mastery bars, bottom-anchored primary actions. */
:root{
  --navy:#0a1628; --navy2:#1b2a44; --gold:#c9a227; --gold-bright:#f5c518;
  --bg:#f7f5ef; --card:#ffffff; --line:#ddd6c2; --text:#101828;
  --muted:#5b6675; --muted2:#8a93a3; --good:#1e7d4d; --bad:#b42318;
  --radius:14px;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--text);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  font-size:16px;line-height:1.5}
a{color:var(--navy2)}
button{font:inherit;cursor:pointer}
button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid var(--gold-bright);outline-offset:2px}
.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}
.app{max-width:430px;margin:0 auto;min-height:100vh;background:var(--bg);padding-bottom:24px}
header.top{background:var(--navy);color:#fff;padding:14px 16px 12px;position:sticky;top:0;z-index:10}
header.top .brand{display:flex;align-items:center;gap:10px;font-weight:800;font-size:21px;letter-spacing:.02em}
header.top .brand img{height:32px;width:auto;display:block}
header.top .tag{font-size:12px;color:#c8d0dc;margin:2px 0 0}
header.top .tag b{color:var(--gold-bright)}
.offline-banner{display:none;background:var(--gold-bright);color:#1a1a1a;text-align:center;
  font-size:13px;font-weight:700;padding:8px 12px}
.offline-banner.show{display:block}
main{padding:14px 14px 0}
h1{font-size:24px;line-height:1.25;margin:6px 0 4px}
h2{font-size:19px;margin:18px 0 8px}
h3{font-size:16px;margin:0 0 6px}
p{margin:8px 0}
.eyebrow{font-size:12px;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);font-weight:700;margin:0}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:16px;margin:12px 0}
.card--navy{background:var(--navy);color:#fff;border-color:var(--navy)}
.card--navy .muted{color:#c8d0dc}
.muted{color:var(--muted);font-size:14px}
.small{font-size:13px}
.badge{display:inline-block;font-size:11px;font-weight:800;letter-spacing:.06em;text-transform:uppercase;
  background:#fff8e1;border:1px solid var(--gold);color:#6b5310;border-radius:999px;padding:3px 9px}
.badge--airgap{background:#eef4ff;border-color:#2a4a8f;color:#1d3a7a}
.badge--sample{background:#fff8e1;border-color:var(--gold);color:#6b5310}
.streak-row{display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap;align-items:center}
.streak-row .big{font-size:22px;font-weight:800}
.stat-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin:12px 0}
.stat{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:12px}
.stat .n{font-size:22px;font-weight:800}
.stat .l{font-size:12px;color:var(--muted);text-transform:uppercase;letter-spacing:.06em;font-weight:700}
/* Segmented path switcher — always visible on Home */
.seg{display:flex;background:#ece7d8;border:1px solid var(--line);border-radius:999px;padding:4px;gap:4px;margin:12px 0}
.seg button{flex:1;border:0;background:transparent;border-radius:999px;min-height:44px;font-weight:700;padding:8px 6px}
.seg button[aria-selected="true"]{background:var(--navy);color:#fff}
.seg button:disabled{opacity:.55}
/* Buttons — thumb-zone: primary actions ≥44px, full-width in action area */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;
  min-height:48px;padding:12px 18px;border-radius:999px;border:0;
  background:var(--gold);color:#1a1a1a;font-weight:800;font-size:16px;width:100%;text-align:center}
.btn--navy{background:var(--navy);color:#fff}
.btn--ghost{background:transparent;border:2px solid var(--navy2);color:var(--navy2)}
.btn--quiet{background:#eee8d8;color:var(--navy2)}
.btn:disabled{opacity:.5;cursor:not-allowed}
.btn-row{display:flex;gap:10px}
.btn-row .btn{flex:1}
.actions{margin:16px 0 4px}
/* Option buttons */
.opts{display:grid;gap:10px;margin:14px 0}
.opt{width:100%;text-align:left;min-height:52px;padding:12px 14px;border-radius:12px;
  border:2px solid var(--line);background:#fff;font-size:16px;display:flex;gap:10px;align-items:flex-start}
.opt .letter{font-weight:800;color:var(--navy2);flex:0 0 22px}
.opt.correct{border-color:var(--good);background:#e8f6ee}
.opt.incorrect{border-color:var(--bad);background:#fdecea}
.opt:disabled{cursor:default;opacity:1}
.opt:disabled:not(.correct):not(.incorrect){opacity:.6}
.feedback{border-radius:12px;padding:12px 14px;margin:12px 0;font-size:15px}
.feedback.good{background:#e8f6ee;border:1px solid var(--good)}
.feedback.bad{background:#fdecea;border:1px solid var(--bad)}
.progress{height:10px;background:#ece7d8;border-radius:999px;overflow:hidden;margin:8px 0}
.progress > div{height:100%;background:var(--gold);border-radius:999px;transition:width .2s}
.mastery-row{margin:12px 0}
.mastery-row .label{display:flex;justify-content:space-between;font-size:14px}
.mastery-row .label b{font-weight:700}
.mastery-row .bar{height:12px;background:#ece7d8;border-radius:999px;overflow:hidden;margin-top:4px}
.mastery-row .bar > div{height:100%;background:var(--navy2);border-radius:999px}
.mastery-row .bar > div.gold{background:var(--gold)}
/* Plan views — milestones, picker chips, replan, nudge (ported patterns) */
.nudge{display:flex;align-items:center;gap:8px;margin:0 0 4px;font-size:13px;line-height:20px;color:var(--muted)}
.nudge span{flex:1 1 auto;min-width:0;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.nudge-link{flex:none;background:none;border:0;color:#6b5310;font-size:13px;font-family:inherit;font-weight:700;cursor:pointer;text-decoration:underline;text-underline-offset:3px;padding:12px 4px;min-height:44px;white-space:nowrap}
.nudge-link:disabled{opacity:.6;cursor:not-allowed;text-decoration:none}
.nudge-x{flex:none;background:none;border:0;color:var(--muted);font-size:18px;line-height:1;cursor:pointer;padding:12px;min-height:44px;min-width:44px}
.chips{display:flex;flex-wrap:wrap;gap:8px;margin:10px 0}
.chip{min-height:44px;padding:8px 14px;border-radius:999px;border:2px solid var(--line);background:#fff;font-weight:700;cursor:pointer}
.chip.on{border-color:var(--gold);background:#fff8e1}
.link{background:none;border:0;color:var(--navy2);text-decoration:underline;padding:0;font-weight:700;cursor:pointer;font-size:14px}
.radio{display:block;margin:10px 0;font-size:15px}
.radio input{accent-color:var(--navy2);min-width:18px;min-height:18px;vertical-align:middle}
.milestones{list-style:none;padding:0;margin:0}
.milestones li{font-size:15px;line-height:28px}
.milestone-flag{color:#6b5310;font-weight:700}
.week summary{cursor:pointer;padding:10px 0;font-size:15px}
.week p{margin:4px 0 12px}
.topic-order{padding-left:22px;margin:10px 0}
.topic-order li{margin:8px 0;font-size:15px}
.topic-order li span{display:inline-block;min-width:190px}
.mini{min-height:36px;padding:6px 10px;border-radius:8px;border:2px solid var(--line);background:#fff;font-weight:700;font-size:13px;cursor:pointer}
.mini:disabled{opacity:.45;cursor:not-allowed}
label.field select{display:block;width:100%;margin-top:6px;min-height:48px;font:inherit;padding:10px 12px;border:2px solid var(--line);border-radius:10px;background:#fff}
details.card summary{cursor:pointer}
label.field{display:block;margin:12px 0;font-weight:700;font-size:15px}
label.field input,label.field select{display:block;width:100%;margin-top:6px;min-height:48px;
  font:inherit;padding:10px 12px;border:2px solid var(--line);border-radius:10px;background:#fff}
.choice-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin:10px 0}
.choice-grid button{min-height:52px;border-radius:12px;border:2px solid var(--line);background:#fff;font-weight:700;padding:10px 8px}
.choice-grid button[aria-pressed="true"]{border-color:var(--gold);background:#fff8e1}
.choice-grid button.full{grid-column:1/-1}
nav.bottom{display:flex;gap:6px;padding:10px 12px;position:sticky;bottom:0;background:#fff;border-top:1px solid var(--line);max-width:430px;margin:14px auto 0}
nav.bottom button{flex:1;border:0;background:transparent;min-height:44px;border-radius:10px;font-weight:700;font-size:13px;color:var(--navy2)}
nav.bottom button.active{background:var(--navy);color:#fff}
footer.site{padding:16px;text-align:center;font-size:12px;color:var(--muted)}
.timer{font-variant-numeric:tabular-nums;font-weight:800}
.end-score{font-size:56px;font-weight:800;line-height:1;margin:8px 0}
.kv{display:flex;justify-content:space-between;padding:8px 0;border-bottom:1px solid #eee8d8;font-size:15px}
.kv:last-child{border-bottom:0}
hr.sep{border:0;border-top:1px solid var(--line);margin:16px 0}
dialog{border:1px solid var(--line);border-radius:16px;padding:20px;max-width:380px;width:calc(100% - 32px)}
dialog::backdrop{background:rgba(10,22,40,.55)}
@media (max-width:340px){.stat-grid{grid-template-columns:1fr}.btn-row{flex-direction:column}}