/* TEEFU · IGCSE Biology 14–15 — same restrained system as the DGT channel: one violet, black/white/grey, whitespace */
:root{--violet:#6A2FE0;--violet-ink:#6A2FE0;--leaf:#2F8F5B;--surface:#fff;--raised:#F5F4F8;--ink:#14121C;--muted:#5F5B6B;--line:#E4E2EA;--bad:#C8323B;
  --sans:"Manrope","Noto Sans SC",system-ui,sans-serif;color-scheme:light}
@media (prefers-color-scheme:dark){:root{--violet-ink:#B8A2FF;--surface:#0B0920;--raised:#16122E;--ink:#F4F2FA;--muted:#A6A1B8;--line:#2A2640;color-scheme:dark}}
*{box-sizing:border-box}[hidden]{display:none!important}
html,body{margin:0;background:var(--surface);color:var(--ink)}
body{font:16px/26px var(--sans);-webkit-font-smoothing:antialiased}
button{font:inherit;color:inherit}
:focus-visible{outline:2px solid var(--violet-ink);outline-offset:2px}
.app{max-width:620px;margin:0 auto;min-height:100dvh;padding:calc(env(safe-area-inset-top,0px) + 12px) 16px calc(env(safe-area-inset-bottom,0px) + 96px)}
.boot{margin:40vh auto 0;text-align:center;font:800 26px var(--sans);color:var(--violet-ink)}
.top{display:flex;align-items:center;gap:10px;min-height:44px}
.brand{display:flex;align-items:center;gap:8px;text-decoration:none;color:var(--ink);font-weight:800}
.brand img{height:24px}
.top .chan{color:var(--muted);font-size:13px;font-weight:700;border-left:1px solid var(--line);padding-left:10px}
.top .gap{flex:1}
.zh-toggle{appearance:none;border:1px solid var(--line);background:var(--surface);border-radius:99px;padding:6px 12px;font-size:13px;font-weight:700;cursor:pointer;min-height:36px}
.zh-toggle[aria-pressed="true"]{background:var(--violet);border-color:var(--violet);color:#fff}
main{display:flex;flex-direction:column;gap:14px;padding-top:12px;animation:fade .3s ease both}
@keyframes fade{from{opacity:0;transform:translateY(4px)}to{opacity:1;transform:none}}
h1{font-size:27px;line-height:34px;margin:0}h2{font-size:18px;line-height:26px;margin:8px 0 0}h3{font-size:15px;margin:0 0 4px;color:var(--violet-ink)}
.kicker{margin:0;font-size:12px;letter-spacing:.6px;font-weight:800;color:var(--violet-ink);text-transform:uppercase}
.sub{margin:0;color:var(--muted);font-size:14px;line-height:22px}
.zh{color:var(--muted);font-size:14px;line-height:22px;margin:4px 0 0}
.hero{display:grid;grid-template-columns:120px 1fr;gap:16px;align-items:center}
.hero img{width:120px;height:auto}
.speech{background:var(--raised);border-radius:4px 18px 18px 18px;padding:14px 16px}
.speech p{margin:0 0 8px}.speech p:last-child{margin:0}
.motto{font-weight:800;color:var(--violet-ink)}
.card{appearance:none;border:1px solid var(--line);background:var(--surface);border-radius:16px;padding:14px 16px;text-align:left;display:grid;gap:3px;cursor:pointer;width:100%}
.card b{font-size:17px}.card small{color:var(--muted);font-size:13.5px;line-height:20px}
.card .num{font-size:12px;font-weight:800;color:var(--violet-ink)}
.card.done{border-color:var(--violet-ink)}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:8px}
.list{display:grid;gap:8px;margin:0;padding:0;list-style:none}
.row{display:flex;gap:8px;flex-wrap:wrap}
.btn{appearance:none;border:0;cursor:pointer;font-weight:800;font-size:16px;padding:13px 20px;border-radius:12px;background:var(--violet);color:#fff;min-height:48px}
.btn.quiet{background:var(--raised);color:var(--ink)}.btn.wide{width:100%}.btn.small{padding:8px 14px;font-size:14px;min-height:40px}
.link{appearance:none;border:0;background:none;color:var(--violet-ink);font-weight:800;font-size:14px;cursor:pointer;padding:8px 0;min-height:44px}
.lo{border-left:3px solid var(--leaf);padding:2px 0 2px 12px;font-size:14px;line-height:22px;color:var(--muted)}
.box{background:var(--raised);border-radius:14px;padding:12px 14px}
.box p{margin:0}
.chain{display:flex;flex-wrap:wrap;gap:6px;align-items:center;margin:0;padding:0;list-style:none}
.chain li{background:color-mix(in srgb,var(--leaf) 12%,var(--surface));border-radius:10px;padding:6px 10px;font-size:14px;line-height:20px}
.chain li+li::before{content:"→";margin-right:6px;color:var(--muted)}
.lens{border-left:3px solid var(--violet);padding:2px 0 2px 12px}
.lens p{margin:0}
.q .stem{font-size:18px;line-height:27px;font-weight:700;margin:0}
.opts{list-style:none;margin:12px 0 0;padding:0;display:grid;gap:8px}
.opt{appearance:none;border:0;width:100%;text-align:left;background:var(--raised);border-radius:12px;padding:12px 14px;display:flex;gap:12px;cursor:pointer;font-size:16px;line-height:24px;min-height:48px}
.opt .k{font-weight:800;color:var(--muted)}
.opt.right{background:var(--violet);color:#fff}.opt.right .k{color:#fff}
.opt.wrong{background:color-mix(in srgb,var(--bad) 14%,var(--surface))}
.opt.tried{opacity:.5}
.opt[disabled]{cursor:default}
.hint{background:color-mix(in srgb,#F2A33A 16%,var(--surface));border-radius:12px;padding:10px 14px;font-size:15px}
.ok{color:var(--violet-ink);font-weight:800}.no{color:var(--bad);font-weight:800}
textarea{width:100%;min-height:120px;border:1px solid var(--line);border-radius:12px;padding:12px;font:16px/24px var(--sans);background:var(--surface);color:var(--ink);resize:vertical}
.points{list-style:none;margin:0;padding:0;display:grid;gap:6px}
.points label{display:flex;gap:10px;align-items:flex-start;background:var(--raised);border-radius:10px;padding:10px 12px;cursor:pointer}
.points input{margin-top:5px;width:18px;height:18px;accent-color:var(--violet)}
.clue{display:flex;gap:10px;align-items:flex-start;background:var(--raised);border-radius:12px;padding:10px 12px}
.clue b{font-size:12px;color:var(--violet-ink);min-width:44px}
.meter{height:8px;border-radius:99px;background:var(--raised);overflow:hidden}
.meter span{display:block;height:100%;background:var(--violet);border-radius:99px}
.stat{display:grid;grid-template-columns:1fr 2fr auto;gap:10px;align-items:center;font-size:14px}
.stat small{color:var(--muted);min-width:5.5em;text-align:right}
.bar{display:flex;gap:2px;height:10px}.bar span{flex:1;background:var(--line);border-radius:2px}.bar span.r{background:var(--violet)}.bar span.w{background:var(--bad)}
figure.viz{margin:0;background:var(--raised);border-radius:14px;padding:10px}
figure.viz svg{display:block;width:100%;height:auto}
figure.viz figcaption{font-size:13px;color:var(--muted);margin-top:6px}
.tabs{position:fixed;inset-inline:0;bottom:0;background:var(--surface);border-top:1px solid var(--line);padding-bottom:env(safe-area-inset-bottom,0px);z-index:5}
.tabs nav{max-width:620px;margin:0 auto;display:grid;grid-template-columns:repeat(3,1fr)}
.tab{appearance:none;border:0;background:none;padding:9px 4px 11px;display:grid;justify-items:center;gap:1px;cursor:pointer;color:var(--muted)}
.tab b{font-size:13.5px}.tab small{font-size:11px}
.tab[aria-current="page"]{color:var(--violet-ink)}
.note{font-size:12px;line-height:19px;color:var(--muted);margin:10px 0 0}
.chips{display:flex;flex-wrap:wrap;gap:8px}
.chip{appearance:none;border:1px solid var(--line);background:var(--surface);border-radius:99px;padding:7px 12px;font-size:14px;cursor:pointer;min-height:38px}
.chip[aria-pressed="true"]{background:var(--violet);border-color:var(--violet);color:#fff}
@media (prefers-reduced-motion:reduce){main{animation:none}}

.stem.scan{line-height:34px}
.word{appearance:none;border:0;background:none;padding:2px 1px;border-radius:6px;font:inherit;cursor:pointer;color:inherit}
.word[aria-pressed="true"],mark{background:color-mix(in srgb,#F2A33A 40%,transparent);color:inherit;border-radius:6px;padding:0 2px}
.btn[disabled]{opacity:.45;cursor:default}