:root{--bg:#fafaf9;--fg:#1c1917;--mut:#78716c;--line:#e7e5e4;--card:#fff;--acc:#0f766e;--acc-fg:#fff;--ok:#15803d;--bad:#b91c1c;--okbg:#f0fdf4;--badbg:#fef2f2}
@media(prefers-color-scheme:dark){:root{--bg:#161514;--fg:#f5f5f4;--mut:#a8a29e;--line:#2e2c2a;--card:#1f1d1b;--acc:#2dd4bf;--acc-fg:#042f2e;--ok:#4ade80;--bad:#f87171;--okbg:#0f2417;--badbg:#2a1414}}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--fg);font:16px/1.55 system-ui,-apple-system,"Segoe UI",Roboto,sans-serif}
header{display:flex;flex-wrap:wrap;gap:.5rem 1.25rem;align-items:center;justify-content:space-between;max-width:720px;margin:0 auto;padding:1rem 1rem .5rem}
.brand{font-weight:650;color:var(--fg);text-decoration:none}
nav{display:flex;flex-wrap:wrap;gap:.25rem 1rem}
nav a{color:var(--mut);text-decoration:none;font-size:.95rem;padding:.25rem 0;border-bottom:2px solid transparent}
nav a:hover,nav a.on{color:var(--fg);border-color:var(--acc)}
main{max-width:720px;margin:0 auto;padding:1rem 1rem 4rem}
h1{font-size:1.5rem;margin:.5rem 0 .25rem}h2{font-size:1.05rem;margin:1.5rem 0 .5rem}h3{font-size:.9rem;color:var(--mut);font-weight:600;margin:1.25rem 0 .5rem}
p{margin:.5rem 0}.mut,.src,.hint{color:var(--mut);font-size:.9rem}
a{color:var(--acc)}
button,select{font:inherit;color:inherit;background:var(--card);border:1px solid var(--line);border-radius:10px;padding:.6rem 1rem;min-height:44px;cursor:pointer}
button:hover,select:hover{border-color:var(--mut)}
button:focus-visible,.card:focus-visible,a:focus-visible,select:focus-visible{outline:2px solid var(--acc);outline-offset:2px}
button.primary{background:var(--acc);color:var(--acc-fg);border-color:var(--acc);font-weight:600}
button:disabled{cursor:default;opacity:1}
.tiles{display:grid;gap:.75rem;margin:1.25rem 0}
.tile{display:block;padding:1rem 1.25rem;border:1px solid var(--line);border-radius:12px;background:var(--card);color:var(--fg);text-decoration:none}
.tile:hover{border-color:var(--acc)}.tile b{display:block;font-size:1.05rem}.tile span{color:var(--mut);font-size:.9rem}
.chips{display:flex;flex-wrap:wrap;gap:.4rem}
.chip{min-height:36px;padding:.3rem .75rem;border-radius:999px;font-size:.9rem}
.chip.on{background:var(--acc);color:var(--acc-fg);border-color:var(--acc)}
.chip small{opacity:.7;margin-left:.25rem}
.row{display:flex;flex-wrap:wrap;gap:.5rem;align-items:center;margin:1rem 0}
.seg{display:inline-flex}.seg button{border-radius:0;margin-left:-1px}.seg button:first-child{border-radius:10px 0 0 10px;margin:0}.seg button:last-child{border-radius:0 10px 10px 0}
.seg button.on{background:var(--acc);color:var(--acc-fg);border-color:var(--acc)}
label.chk{display:flex;gap:.5rem;align-items:center;cursor:pointer}
.meta{display:flex;justify-content:space-between;gap:1rem;color:var(--mut);font-size:.85rem;margin:.5rem 0}
.bar{height:3px;background:var(--line);border-radius:2px;margin-bottom:1rem}.bar i{display:block;height:100%;background:var(--acc);border-radius:2px}
.card{border:1px solid var(--line);border-radius:14px;background:var(--card);padding:1.5rem;min-height:200px;cursor:pointer}
.big{font-size:1.2rem;line-height:1.45;margin:0}.ans{font-size:1.05rem;margin:.75rem 0 0}
.card hr{border:0;border-top:1px solid var(--line);margin:1rem 0}
.deep{margin-top:1rem;padding:.75rem 1rem;border-left:3px solid var(--acc);background:var(--bg);border-radius:0 8px 8px 0;font-size:.95rem;white-space:pre-line}
.opts{display:grid;gap:.5rem;margin:1rem 0}
.opt{text-align:left;display:flex;gap:.75rem;align-items:flex-start}.opt b{color:var(--mut);min-width:1.1rem}
.opt.right{border-color:var(--ok);background:var(--okbg)}.opt.wrong{border-color:var(--bad);background:var(--badbg)}
.fb{font-weight:600}.fb.ok{color:var(--ok)}.fb.bad{color:var(--bad)}
.change{margin:1rem 0;padding:.75rem 1rem;border:1px solid var(--line);border-radius:10px;background:var(--card);font-size:.95rem}
.tag{display:inline-block;padding:0 .5rem;border-radius:999px;border:1px solid var(--line);font-size:.8rem}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:.75rem}
.thumb{padding:.4rem;text-align:left;display:block}.thumb img{width:100%;aspect-ratio:4/3;object-fit:cover;border-radius:6px;display:block}.thumb span{display:block;font-size:.8rem;margin-top:.3rem}
details{border-top:1px solid var(--line);padding:.5rem 0}summary{cursor:pointer;font-weight:600;padding:.4rem 0}
dialog{border:0;padding:0;background:transparent;max-width:96vw;max-height:96vh}dialog::backdrop{background:rgba(0,0,0,.75)}dialog img{max-width:96vw;max-height:94vh;display:block;border-radius:8px;background:#fff}
.note{font-size:.85rem;color:var(--mut);border-top:1px solid var(--line);margin-top:2rem;padding-top:.75rem}