:root{
  --paper:#f5f0e6; --paper-2:#ece5d6; --paper-3:#e2d9c6;
  --ink:#1c1b18; --ink-2:#55503f; --ink-3:#8a8370;
  --line:rgba(28,27,24,.14);
  --diag:#2b4c7e; --pit:#b8432a; --strat:#2c7556; --gold:#b9852e;
  --good:#2c7556; --bad:#b8432a;
  --bg:var(--paper); --surface:#fbf8f2; --surface-2:var(--paper-2);
  --text:var(--ink); --muted:var(--ink-2); --faint:var(--ink-3);
  --ai-bubble:#efe8da; --user-bubble:#24324a; --user-text:#f3efe6;
  --radius:14px;
}
@media (prefers-color-scheme: dark){
  :root:not([data-theme="light"]){
    --bg:#121314; --surface:#1b1c1e; --surface-2:#24262a;
    --text:#ece7dc; --muted:#b3ac9c; --faint:#857f72; --line:rgba(236,231,220,.13);
    --diag:#7fa3dc; --pit:#ec7a5f; --strat:#5fbf93; --gold:#e0b25c; --good:#5fbf93; --bad:#ec7a5f;
    --ai-bubble:#25272b; --user-bubble:#2f4469; --user-text:#eef1f7;
  }
}
:root[data-theme="dark"]{
  --bg:#121314; --surface:#1b1c1e; --surface-2:#24262a;
  --text:#ece7dc; --muted:#b3ac9c; --faint:#857f72; --line:rgba(236,231,220,.13);
  --diag:#7fa3dc; --pit:#ec7a5f; --strat:#5fbf93; --gold:#e0b25c; --good:#5fbf93; --bad:#ec7a5f;
  --ai-bubble:#25272b; --user-bubble:#2f4469; --user-text:#eef1f7;
}

*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--text);font:16px/1.5 'IBM Plex Sans',system-ui,sans-serif;min-height:100vh}
button{font:inherit;color:inherit}
.wrap{max-width:560px;margin:0 auto;padding:0 16px 48px}
.serif{font-family:'Fraunces',Georgia,serif;font-optical-sizing:auto}
.mono{font-family:'IBM Plex Mono',ui-monospace,monospace}

/* top bar */
.top{position:sticky;top:0;z-index:10;background:var(--bg);border-bottom:1px solid var(--line);margin:0 -16px 20px;padding:10px 16px 0}
.top-row{display:flex;justify-content:space-between;align-items:center;gap:8px}
.brand{font-family:'Fraunces',Georgia,serif;font-weight:600;font-size:15px;letter-spacing:.01em}
.linkbtn{background:none;border:none;padding:6px 0;color:var(--muted);font-size:13px;text-decoration:underline;text-underline-offset:3px;cursor:pointer}
.tabs{display:flex;gap:4px;margin-top:8px}
.tab{flex:1;font-size:11.5px;letter-spacing:.08em;text-transform:uppercase;text-align:center;padding:7px 0 8px;color:var(--faint);border-bottom:3px solid transparent}
.tab.on{color:var(--text);font-weight:600}
.tab[data-p="diagnose"].on{border-color:var(--diag)} .tab[data-p="pitfalls"].on{border-color:var(--pit)} .tab[data-p="strategies"].on{border-color:var(--strat)}
.tab .lock{opacity:.7}
.prog{height:3px;background:var(--surface-2);margin:0 -16px}
.prog i{display:block;height:100%;background:var(--accent,var(--diag));transition:width .3s ease}
@media (prefers-reduced-motion: reduce){.prog i{transition:none}}

/* type */
h1{font-family:'Fraunces',Georgia,serif;font-weight:650;font-size:clamp(32px,9vw,44px);line-height:1.03;margin:8px 0 12px;letter-spacing:-.01em;text-wrap:balance}
h2{font-family:'Fraunces',Georgia,serif;font-weight:600;font-size:26px;line-height:1.12;margin:4px 0 10px;text-wrap:balance}
h3{font-size:15px;margin:0 0 8px}
p{margin:0 0 14px}
.lead{font-size:17px;color:var(--muted)}
.kicker{font:600 11.5px/1 'IBM Plex Mono',monospace;letter-spacing:.1em;text-transform:uppercase;color:var(--accent,var(--diag));margin:6px 0 10px}
.muted{color:var(--muted)} .faint{color:var(--faint)} .small{font-size:13.5px}

/* blocks */
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:18px}
.stack>*+*{margin-top:12px}
.stem{font-size:18px;line-height:1.45;margin:0 0 14px}
.quote{border-left:3px solid var(--accent,var(--diag));background:var(--surface-2);padding:12px 14px;border-radius:0 10px 10px 0;font-size:15px;margin:0 0 14px;white-space:pre-wrap}

/* buttons */
.btn{appearance:none;border:none;border-radius:12px;padding:15px 20px;font-weight:600;font-size:16px;cursor:pointer;width:100%;background:var(--text);color:var(--bg)}
.btn.accent{background:var(--accent,var(--diag));color:#fff}
.btn.ghost{background:transparent;color:var(--text);border:1.5px solid var(--line)}
.btn:disabled{opacity:.4;cursor:default}
.btn:focus-visible,.opt:focus-visible,.chip:focus-visible{outline:3px solid var(--gold);outline-offset:2px}
.opts{display:grid;gap:10px}
.opt{appearance:none;text-align:left;width:100%;background:var(--surface);border:1.5px solid var(--line);border-radius:12px;padding:14px 15px;font-size:15.5px;line-height:1.4;cursor:pointer;display:flex;gap:12px;align-items:flex-start}
.opt .l{font:600 12px/1.9 'IBM Plex Mono',monospace;color:var(--faint);flex:none;width:18px}
.opt.sel{border-color:var(--accent,var(--diag));background:color-mix(in srgb,var(--accent,var(--diag)) 10%,var(--surface))}
.opt.ok{border-color:var(--good);background:color-mix(in srgb,var(--good) 13%,var(--surface))}
.opt.no{border-color:var(--bad);background:color-mix(in srgb,var(--bad) 11%,var(--surface))}
.opt.dim{opacity:.55}
.opt[disabled]{cursor:default}
.conf{margin-top:18px}
.conf-row{display:grid;grid-template-columns:repeat(4,1fr);gap:6px}
.chip{appearance:none;border:1.5px solid var(--line);background:var(--surface);border-radius:10px;padding:11px 4px;font-size:13px;font-weight:500;cursor:pointer;line-height:1.2}
.chip.sel{border-color:var(--accent,var(--diag));background:var(--accent,var(--diag));color:#fff}
.row{display:flex;gap:10px} .row>*{flex:1}
.spacer{height:18px}

/* stepper */
.stepper{display:flex;align-items:center;justify-content:center;gap:18px;margin:10px 0 6px}
.stepper button{width:52px;height:52px;border-radius:50%;border:1.5px solid var(--line);background:var(--surface);font-size:24px;cursor:pointer}
.stepper .n{font:600 48px/1 'IBM Plex Mono',monospace;min-width:70px;text-align:center}

/* feedback */
.reveal{margin-top:16px;padding-top:14px;border-top:1px dashed var(--line)}
.verdict{font:600 12px/1 'IBM Plex Mono',monospace;letter-spacing:.08em;text-transform:uppercase;margin-bottom:8px}
.verdict.ok{color:var(--good)} .verdict.no{color:var(--bad)}
.evidence{background:var(--surface-2);border-radius:10px;padding:12px 14px;font-size:14.5px;margin-top:12px}
.evidence b{font:600 11px/1 'IBM Plex Mono',monospace;letter-spacing:.08em;text-transform:uppercase;display:block;margin-bottom:6px;color:var(--muted)}

/* chat transcript */
.chat{display:flex;flex-direction:column;gap:8px;margin:0 0 14px}
.bub{max-width:88%;padding:10px 13px;border-radius:14px;font-size:14.5px;line-height:1.45;white-space:pre-wrap;overflow-wrap:anywhere}
.bub.user{align-self:flex-end;background:var(--user-bubble);color:var(--user-text);border-bottom-right-radius:4px}
.bub.ai{align-self:flex-start;background:var(--ai-bubble);border-bottom-left-radius:4px}
.meta{font:500 11.5px/1.3 'IBM Plex Mono',monospace;color:var(--faint);margin:-4px 0 10px}

/* results */
.big{font:600 56px/1 'IBM Plex Mono',monospace;letter-spacing:-.02em}
.gapline{font-size:17px;line-height:1.45}
.dimrow{display:flex;justify-content:space-between;align-items:center;padding:10px 0;border-bottom:1px solid var(--line);gap:12px}
.dimrow:last-child{border-bottom:none}
.dots{display:flex;gap:5px;flex:none}
.dots i{width:12px;height:12px;border-radius:50%;background:var(--surface-2);border:1.5px solid var(--line)}
.dots i.on{background:var(--diag);border-color:var(--diag)}
.band{font:600 11px/1 'IBM Plex Mono',monospace;letter-spacing:.06em;text-transform:uppercase;color:var(--muted);width:64px;text-align:right}
.meter{position:relative;height:30px;margin:14px 0 4px}
.meter .track{position:absolute;left:0;right:0;top:13px;height:4px;border-radius:4px;background:var(--surface-2)}
.meter .mk{position:absolute;top:0;transform:translateX(-50%);font:600 10.5px/1 'IBM Plex Mono',monospace;text-align:center;white-space:nowrap}
.meter .mk::after{content:"";display:block;width:12px;height:12px;border-radius:50%;margin:3px auto 0;background:currentColor}
.review details{border-bottom:1px solid var(--line);padding:10px 0}
.review summary{cursor:pointer;font-size:14.5px;list-style:none;display:flex;gap:10px}
.review summary::-webkit-details-marker{display:none}
.review .mark{font:600 13px/1.5 'IBM Plex Mono',monospace;flex:none;width:16px}
.review .mark.ok{color:var(--good)} .review .mark.no{color:var(--bad)}
.review .body{font-size:14px;color:var(--muted);padding:8px 0 4px 26px}

/* wait screen */
.wait{text-align:center;padding:40px 8px}
.pulse{width:14px;height:14px;border-radius:50%;background:var(--accent,var(--diag));margin:0 auto 18px;animation:pulse 1.6s ease-in-out infinite}
@keyframes pulse{0%,100%{opacity:.25;transform:scale(.8)}50%{opacity:1;transform:scale(1)}}
@media (prefers-reduced-motion: reduce){.pulse{animation:none}}

/* live AI */
.grade{display:inline-block;font:600 30px/1 'IBM Plex Mono',monospace;padding:8px 12px;border-radius:10px;background:var(--surface-2);margin-right:10px;vertical-align:middle}
.delta{font:600 15px 'IBM Plex Mono',monospace}
.delta.up{color:var(--bad)} .delta.same{color:var(--good)}
textarea{width:100%;font:inherit;font-size:15px;padding:12px;border-radius:10px;border:1.5px solid var(--line);background:var(--surface);color:var(--text);resize:vertical;min-height:72px}

/* strategies */
.prompt-box{position:relative;background:var(--surface-2);border-radius:10px;padding:12px 14px 44px;font:14px/1.5 'IBM Plex Mono',monospace;white-space:pre-wrap}
.copy{position:absolute;right:8px;bottom:8px;border:1.5px solid var(--line);background:var(--surface);border-radius:8px;padding:6px 12px;font-size:13px;cursor:pointer}
.pick{display:grid;gap:8px}
.pick .opt .tick{width:20px;height:20px;border:1.5px solid var(--line);border-radius:6px;flex:none;display:grid;place-items:center;font-size:13px}
.pick .opt.sel .tick{background:var(--strat);border-color:var(--strat);color:#fff}

/* take-home card */
.takehome{border:2px solid var(--text);border-radius:18px;padding:20px;background:var(--surface)}
.takehome h2{margin-top:0}
.takehome .habit{border-top:1px solid var(--line);padding:12px 0}
.takehome .habit:first-of-type{border-top:none}

/* sheet */
.sheet{position:fixed;inset:0;z-index:50;background:rgba(0,0,0,.45);display:flex;align-items:flex-end;justify-content:center}
.sheet[hidden]{display:none}
.sheet-in{background:var(--bg);width:100%;max-width:560px;max-height:85vh;overflow:auto;border-radius:18px 18px 0 0;padding:18px 16px 32px}
.src-list li{font-size:13.5px;margin-bottom:10px;overflow-wrap:anywhere;color:var(--muted)}
.toast{position:fixed;left:50%;bottom:22px;transform:translateX(-50%);background:var(--text);color:var(--bg);padding:10px 16px;border-radius:10px;font-size:14px;z-index:60}
.note{font-size:13px;color:var(--faint);line-height:1.5}
[hidden]{display:none!important}