:root {
  --bg: #0f1115; --panel: #181b22; --line: #2a2f3a; --text: #e7e9ee;
  --muted: #9aa3b2; --accent: #6ea8fe; --good: #58d68d; --bad: #ff6b6b;
  --target: #f7b955;
}
* { box-sizing: border-box; }
body {
  margin: 0; background: var(--bg); color: var(--text);
  font: 16px/1.5 system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
}
main { max-width: 540px; margin: 0 auto; padding: 24px 18px 80px; }
header { text-align: center; }
h1 { letter-spacing: .04em; margin: .2em 0 0; }
.date { color: var(--muted); margin: .2em 0 .25em; }
.countdown { color: var(--accent); font-size: .8rem; letter-spacing: .03em; margin: 0 0 1.3em; }

.puzzle { text-align: center; margin-bottom: 14px; }
.word {
  font-size: 2rem; font-weight: 700; letter-spacing: .12em;
  text-transform: uppercase; padding: 10px;
}
.word.start { color: var(--accent); }
.word.target { color: var(--target); }
.arrow { color: var(--muted); font-size: .85rem; letter-spacing: .05em; }

.topnav { display: flex; gap: 8px; justify-content: center; margin: 2px 0 18px; }
button.ghost { background: transparent; color: var(--accent); border: 1px solid var(--line);
  padding: 6px 12px; font-size: .85rem; font-weight: 600; }
button.ghost:hover { border-color: var(--accent); }

.builder { background: var(--panel); border: 1px solid var(--line);
  border-radius: 12px; padding: 14px; }
ol#chain { list-style: none; margin: 0; padding: 0; display: flex;
  flex-direction: column; gap: 8px; }
.row { display: flex; align-items: center; gap: 10px; }
.row .idx { width: 1.4em; color: var(--muted); text-align: right; font-variant-numeric: tabular-nums; }
.row input, .row .fixed {
  flex: 1; padding: 9px 12px; border-radius: 8px; border: 1px solid var(--line);
  background: #0d0f14; color: var(--text); font-size: 1.05rem; letter-spacing: .12em;
  font-weight: 700; text-transform: uppercase;
}
.row input::placeholder { font-weight: 400; letter-spacing: normal; text-transform: none; }
.row .fixed { display: flex; align-items: center; }
.row.startfixed .fixed { color: var(--accent); }
.row.targetfixed .fixed { color: var(--target); }
.row input.ok { border-color: var(--good); }
.row input.err { border-color: var(--bad); }
.row .mark { width: 1.4em; text-align: center; }
.row .mark.ok { color: var(--good); }
.row .mark.err { color: var(--bad); }
.row .del { background: none; border: none; color: var(--muted); cursor: pointer; font-size: 1.1rem; }

.builder-actions { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-top: 12px; }
button { background: var(--accent); color: #07101f; border: none; border-radius: 8px;
  padding: 9px 16px; font-weight: 700; cursor: pointer; white-space: nowrap; }
button:disabled { opacity: .45; cursor: not-allowed; }
#addRow { background: transparent; color: var(--accent); border: 1px solid var(--line); flex-shrink: 0; }
.status { font-size: .9rem; color: var(--muted); min-width: 0; text-align: right; }
.status.good { color: var(--good); }
.status.bad { color: var(--bad); }

.submit-row { display: flex; gap: 10px; margin: 16px 0; }
#name { flex: 1; padding: 9px 12px; border-radius: 8px; border: 1px solid var(--line);
  background: #0d0f14; color: var(--text); }

.results { background: var(--panel); border: 1px solid var(--line); border-radius: 12px; padding: 16px; }
.results h2 { margin: 0 0 6px; }
.yourbest { color: var(--good); font-weight: 700; }
.yoursolution { color: var(--text); font-size: .95rem; letter-spacing: .04em; margin: 2px 0 8px; }
.yoursolution .w { font-weight: 700; }
.reveal { color: var(--target); }
.histo { display: flex; flex-direction: column; gap: 4px; margin: 12px 0; }
.bar-row { display: flex; align-items: center; gap: 8px; font-size: .9rem; }
.bar-row .lbl { width: 5.5em; color: var(--muted); }
.bar { height: 16px; background: var(--accent); border-radius: 4px; min-width: 2px; }
.bar.you { background: var(--good); }
.leaderboard { padding-left: 1.4em; }
.leaderboard li { margin: 2px 0; }
.leaderboard .s { color: var(--muted); }

/* ---------- modal ---------- */
.modal-overlay {
  position: fixed; inset: 0; background: rgba(0,0,0,.6);
  display: flex; align-items: flex-start; justify-content: center;
  padding: 28px 14px; overflow-y: auto; z-index: 50;
}
/* the explicit display:flex above would otherwise defeat the `hidden` attribute */
.modal-overlay[hidden] { display: none; }
.modal {
  position: relative; background: var(--panel); border: 1px solid var(--line);
  border-radius: 14px; padding: 22px; max-width: 540px; width: 100%;
  box-shadow: 0 18px 50px rgba(0,0,0,.5);
}
.modal-close {
  position: absolute; top: 10px; right: 12px; background: none; border: none;
  color: var(--muted); font-size: 1.5rem; line-height: 1; padding: 4px 8px; cursor: pointer;
}
.modal-close:hover { color: var(--text); }
.modal-body h2 { margin: 0 0 4px; }
.modal-body h3 { margin: 18px 0 8px; }
.modal-body p { color: var(--muted); }

/* help: move chips */
.moves { display: flex; flex-direction: column; gap: 8px; margin: 10px 0; }
.move { display: flex; gap: 10px; align-items: baseline; background: #0d0f14;
  border: 1px solid var(--line); border-radius: 8px; padding: 8px 12px; }
.move .tag { font-weight: 700; color: var(--accent); min-width: 5.2em; }
.move .ex { letter-spacing: .06em; }
.move .ex b { color: var(--text); }
.note { font-size: .88rem; }

/* worked example ladder */
.ladder { list-style: none; margin: 8px 0 0; padding: 0; }
.ladder .w { font-size: 1.15rem; font-weight: 700; letter-spacing: .12em;
  text-transform: uppercase; }
.ladder .w.s0 { color: var(--accent); }
.ladder .w.sN { color: var(--target); }
.ladder .op { color: var(--muted); font-size: .82rem; margin: 2px 0 2px 4px;
  border-left: 2px solid var(--line); padding: 1px 0 1px 12px; }
.ladder .op .combo { color: var(--accent); font-style: italic; }

/* past days */
.daynav { display: flex; align-items: center; justify-content: space-between; gap: 8px; margin: 4px 0 14px; }
.daynav button { padding: 6px 12px; flex-shrink: 0; }
.daynav button:disabled { opacity: .4; }
.daynav .dlabel { font-weight: 700; flex: 1; min-width: 0; text-align: center; font-size: .9rem; }
.solpath { background: #0d0f14; border: 1px solid var(--line); border-radius: 8px;
  padding: 8px 12px; margin: 6px 0; letter-spacing: .05em; }
.solpath .w { font-weight: 700; text-transform: uppercase; }
.solpath .meta { color: var(--muted); font-weight: 400; text-transform: none; letter-spacing: normal; }
.optimal .w { color: var(--good); }
.muted { color: var(--muted); }
.spinner { color: var(--muted); }
.modal-body .bad { color: var(--bad); }