:root {
  --bg: #f6f3ec;
  --paper: #fffdf8;
  --ink: #1d2433;
  --muted: #5f6675;
  --line: #e3ddd0;
  --accent: #c2522d;
  --accent-soft: #f6e2d8;
  --good: #2f7a4f;
  --good-soft: #e1f1e6;
  --bad: #a93a2c;
  --bad-soft: #f8e0dc;
  --hint: #7a5a12;
  --hint-soft: #fbf0d3;
  --navy: #1f2a44;
  --shadow: 0 1px 2px rgba(29, 36, 51, .06), 0 6px 20px rgba(29, 36, 51, .06);
  --serif: "Fraunces", Georgia, serif;
  --sans: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14171f; --paper: #1c2029; --ink: #e9e6df; --muted: #a2a7b3; --line: #2e3442;
    --accent: #ec8a63; --accent-soft: #3a2820; --good: #6cc792; --good-soft: #1d3326;
    --bad: #f08a7c; --bad-soft: #3b211e; --hint: #e9c46a; --hint-soft: #332b17; --navy: #0e1118;
    --shadow: 0 1px 2px rgba(0,0,0,.3), 0 6px 20px rgba(0,0,0,.25);
  }
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 16px/1.6 var(--sans); }
a { color: var(--accent); }
h1, h2, h3 { font-family: var(--serif); font-weight: 700; line-height: 1.2; margin: 0 0 .5em; letter-spacing: -.01em; }
h1 { font-size: clamp(30px, 5vw, 48px); }
h1 em { font-style: normal; color: var(--accent); }
h2 { font-size: clamp(24px, 3.4vw, 32px); }
h3 { font-size: 20px; }
p { margin: 0 0 .8em; }
.muted { color: var(--muted); }
.small { font-size: 14px; }
.eyebrow { text-transform: uppercase; letter-spacing: .14em; font-size: 12px; font-weight: 700; color: var(--accent); margin-bottom: 10px; }
button, input, select, textarea { font: inherit; color: inherit; }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; }

/* Top bar */
.top { background: var(--navy); color: #f3efe6; position: sticky; top: 0; z-index: 20; }
.top-in { max-width: 1120px; margin: 0 auto; padding: 10px 16px; display: flex; align-items: center; gap: 18px; flex-wrap: wrap; }
.brand { display: flex; align-items: center; gap: 10px; color: inherit; text-decoration: none; font-weight: 700; }
.mark { width: 30px; height: 30px; border-radius: 50%; border: 1.5px solid #ec8a63; display: grid; place-items: center; color: #ec8a63; font-size: 20px; }
.tabs { display: flex; gap: 4px; overflow-x: auto; margin-left: auto; scrollbar-width: none; }
.tabs a { color: #cfd3dc; text-decoration: none; padding: 8px 12px; border-radius: 8px; font-size: 14px; font-weight: 500; white-space: nowrap; }
.tabs a:hover { color: #fff; background: rgba(255,255,255,.08); }
.tabs a.on { color: #fff; background: rgba(236,138,99,.22); }

main { max-width: 1120px; margin: 0 auto; padding: 28px 16px 60px; }
.view[hidden] { display: none; }
.hero { padding: 24px 0 18px; max-width: 760px; }
.lede { font-size: 18px; color: var(--muted); }

.panel, .card { background: var(--paper); border: 1px solid var(--line); border-radius: 14px; padding: 22px; box-shadow: var(--shadow); margin-bottom: 18px; }
.panel.tight { padding: 16px 20px; }
.cards3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 16px; margin: 10px 0 22px; }
.card.link { color: inherit; text-decoration: none; display: block; transition: transform .15s, border-color .15s; margin: 0; }
.card.link:hover { transform: translateY(-2px); border-color: var(--accent); }
.tag { display: inline-block; font-size: 12px; font-weight: 600; background: var(--accent-soft); color: var(--accent); padding: 3px 9px; border-radius: 999px; margin-bottom: 10px; }
.steps { padding-left: 20px; margin: 0 0 12px; }
.steps li { margin-bottom: 8px; }

.btn { background: var(--accent); color: #fff; border: 0; border-radius: 9px; padding: 9px 16px; font-weight: 600; cursor: pointer; }
.btn:hover { filter: brightness(1.07); }
.btn.ghost { background: transparent; color: var(--ink); border: 1px solid var(--line); }
.btn.ghost:hover { border-color: var(--accent); }
.btn.small { padding: 6px 11px; font-size: 14px; }
.btn:disabled { opacity: .45; cursor: not-allowed; }
input[type=text], input[type=number], select, textarea { background: var(--bg); border: 1px solid var(--line); border-radius: 9px; padding: 9px 11px; }
textarea { width: 100%; resize: vertical; line-height: 1.55; }
label { font-size: 14px; font-weight: 600; display: inline-flex; flex-direction: column; gap: 5px; }

/* Cycle list */
.cycle-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 14px; }
.cycle-card { background: var(--paper); border: 1px solid var(--line); border-radius: 14px; padding: 18px; cursor: pointer; text-align: left; box-shadow: var(--shadow); transition: transform .15s, border-color .15s; }
.cycle-card:hover { transform: translateY(-2px); border-color: var(--accent); }
.cycle-card h3 { margin-bottom: 4px; }
.stars { color: var(--accent); letter-spacing: 2px; font-size: 14px; }
.status { font-size: 13px; font-weight: 600; margin-top: 8px; }
.status.done { color: var(--good); }
.loopviz { display: flex; align-items: center; gap: 6px; margin: 10px 0 2px; font-family: var(--mono); font-size: 13px; color: var(--muted); }
.loopviz span.n { width: 26px; height: 26px; border-radius: 50%; border: 1.5px solid var(--line); display: grid; place-items: center; font-weight: 600; color: var(--ink); }
.loopviz span.n.ok { border-color: var(--good); background: var(--good-soft); color: var(--good); }

/* Cycle detail */
.detail-head { display: flex; justify-content: space-between; align-items: flex-start; gap: 16px; flex-wrap: wrap; margin-bottom: 16px; }
.timer { font-family: var(--mono); font-size: 28px; font-weight: 600; }
.timer.low { color: var(--bad); }
.timer-box { display: flex; align-items: center; gap: 10px; background: var(--paper); border: 1px solid var(--line); border-radius: 12px; padding: 8px 14px; }
.problem { background: var(--paper); border: 1px solid var(--line); border-radius: 14px; padding: 20px; margin-bottom: 14px; box-shadow: var(--shadow); position: relative; }
.problem .plabel { font-family: var(--mono); font-size: 13px; font-weight: 600; color: var(--accent); margin-bottom: 6px; }
.problem .ptext { font-size: 17px; }
.answer-row { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; margin-top: 12px; }
.answer-row input { width: 150px; }
.feedback { font-size: 14px; font-weight: 600; }
.feedback.ok { color: var(--good); }
.feedback.no { color: var(--bad); }
.hintbox { margin-top: 10px; }
.hint { background: var(--hint-soft); color: var(--ink); border-left: 3px solid var(--hint); border-radius: 6px; padding: 9px 12px; margin-top: 8px; font-size: 15px; }
.hint b.h { color: var(--hint); }
.solution { background: var(--good-soft); border-left: 3px solid var(--good); border-radius: 6px; padding: 11px 14px; margin-top: 10px; font-size: 15px; }
.arrow { text-align: center; color: var(--muted); font-size: 13px; margin: -6px 0 8px; font-family: var(--mono); }
.wayin { background: var(--accent-soft); border-radius: 10px; padding: 12px 16px; margin-bottom: 14px; }
.rubric { width: 100%; border-collapse: collapse; font-size: 14px; margin-top: 8px; }
.rubric td { border-top: 1px solid var(--line); padding: 8px 6px; vertical-align: top; }
.rubric td:first-child { width: 44px; }
.score-line { font-weight: 700; margin-top: 8px; }
.bar { display: flex; gap: 8px; flex-wrap: wrap; margin: 6px 0 14px; }

/* Mystery ops */
.head-row { display: flex; justify-content: space-between; gap: 20px; flex-wrap: wrap; align-items: flex-end; margin-bottom: 14px; }
.head-row > div:first-child { max-width: 700px; }
.ops-controls { display: flex; gap: 10px; align-items: flex-end; flex-wrap: wrap; }
.ops-layout { display: grid; grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr); gap: 16px; }
@media (max-width: 860px) { .ops-layout { grid-template-columns: 1fr; } }
.opchips { display: flex; gap: 8px; margin: 8px 0 12px; flex-wrap: wrap; }
.opbtn { font-size: 22px; width: 54px; height: 46px; border-radius: 10px; border: 1px solid var(--line); background: var(--bg); cursor: pointer; }
.opbtn:hover { border-color: var(--accent); }
.keyrow { display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 10px; }
.keyrow button { min-width: 40px; height: 40px; border-radius: 8px; border: 1px solid var(--line); background: var(--bg); cursor: pointer; font-family: var(--mono); }
.calc-input { width: 100%; font-family: var(--mono); font-size: 20px; padding: 10px 12px; }
.log { font-family: var(--mono); font-size: 14px; max-height: 300px; overflow: auto; border-top: 1px solid var(--line); margin-top: 10px; padding-top: 6px; }
.log div { padding: 3px 0; border-bottom: 1px dashed var(--line); display: flex; justify-content: space-between; gap: 10px; }
.log .err { color: var(--bad); }
.puzzle { border: 1px solid var(--line); border-radius: 12px; padding: 14px; margin-bottom: 10px; background: var(--bg); }
.puzzle.solved { border-color: var(--good); background: var(--good-soft); }
.puzzle .nums { font-family: var(--mono); font-size: 18px; font-weight: 600; }
.puzzle .target { font-family: var(--mono); font-size: 18px; font-weight: 700; color: var(--accent); }
.puzzle input { width: 100%; font-family: var(--mono); margin-top: 8px; }
.setbar { display: flex; justify-content: space-between; align-items: center; gap: 12px; flex-wrap: wrap; margin-bottom: 12px; }
.pill { font-size: 13px; font-weight: 600; padding: 4px 10px; border-radius: 999px; background: var(--accent-soft); color: var(--accent); }
.reveal-ops { font-family: var(--mono); font-size: 15px; }
.tips summary { cursor: pointer; font-weight: 600; }

/* Cipher packs */
.packs { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 16px; }
.pack h3 { margin-bottom: 2px; }
.cipher { font-family: var(--mono); font-size: 14px; background: var(--bg); border: 1px dashed var(--line); border-radius: 8px; padding: 12px; word-break: break-all; white-space: pre-wrap; margin: 8px 0; line-height: 1.7; }
.pack .q { border-top: 1px solid var(--line); padding-top: 12px; margin-top: 12px; }
.teach { font-size: 15px; }
.teach-hidden { filter: blur(6px); user-select: none; }

.foot { text-align: center; color: var(--muted); font-size: 13px; padding: 20px 16px 40px; }

@media (max-width: 600px) {
  .top-in { gap: 8px; }
  .tabs { margin-left: 0; width: 100%; }
  .problem .ptext { font-size: 16px; }
  .panel, .card, .problem { padding: 16px; }
}