:root {
  --bg: #f3f1ee;
  --surface: #ffffff;
  --surface-2: #ece6dc;
  --border: #d8cfc2;
  --ink: #201a17;
  --ink-muted: #6b5f54;
  --accent: #29467a;
  --accent-ink: #ffffff;
  --success: #2f7a4d;
  --success-bg: #e8f3ec;
  --danger: #b3261e;
  --danger-bg: #fbe9e7;
  --warn: #a3641c;
  --warn-bg: #faf0e2;
  --code-bg: #1c1815;
  --code-ink: #f1ece4;
  --code-muted: #9a8d7c;
  --marker-mine: #6ea0e0;
  --marker-theirs: #e0a25f;
  --belt-1: #cbb896;
  --belt-2: #d9a824;
  --belt-3: #d97b29;
  --belt-4: #2f7a4d;
  --belt-5: #2d6ca8;
  --belt-final: #1a1a1a;
  --belt-r1: #5c7a5f;
  --belt-r2: #a35d2e;
  --belt-r3: #6a5a9c;
  --radius: 12px;
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  --font-body: "IBM Plex Sans", system-ui, -apple-system, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #17130f;
    --surface: #211b16;
    --surface-2: #2b2319;
    --border: #453a2c;
    --ink: #f1ece4;
    --ink-muted: #b4a795;
    --accent: #7ea3e0;
    --accent-ink: #0d1420;
    --success: #7fd99a;
    --success-bg: #1c3324;
    --danger: #ff8a80;
    --danger-bg: #3a1f1d;
    --warn: #e0b04f;
    --warn-bg: #3a2c14;
  }
}
:root[data-theme="dark"] {
  --bg: #17130f;
  --surface: #211b16;
  --surface-2: #2b2319;
  --border: #453a2c;
  --ink: #f1ece4;
  --ink-muted: #b4a795;
  --accent: #7ea3e0;
  --accent-ink: #0d1420;
  --success: #7fd99a;
  --success-bg: #1c3324;
  --danger: #ff8a80;
  --danger-bg: #3a1f1d;
  --warn: #e0b04f;
  --warn-bg: #3a2c14;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  line-height: 1.5;
}

h1, h2, h3 { font-family: var(--font-mono); text-wrap: balance; margin: 0; letter-spacing: -0.01em; }
code, .mono { font-family: var(--font-mono); }
a { color: var(--accent); }

.wrap { max-width: 980px; margin: 0 auto; padding: 24px 20px 64px; }

header.top {
  display: flex; flex-wrap: wrap; justify-content: space-between; align-items: flex-end;
  gap: 16px; padding-bottom: 18px; border-bottom: 2px solid var(--border); margin-bottom: 20px;
}
.eyebrow {
  font-family: var(--font-mono); font-size: 12px; letter-spacing: .08em; text-transform: uppercase;
  color: var(--accent); font-weight: 600; margin: 0 0 4px;
}
h1 { font-size: 28px; font-weight: 700; }
.lede { color: var(--ink-muted); font-size: 14px; max-width: 60ch; margin-top: 6px; }

.top-actions { display: flex; gap: 8px; align-items: center; }
.icon-btn {
  font-family: var(--font-mono); font-size: 12.5px; border: 1px solid var(--border);
  background: var(--surface); color: var(--ink-muted); border-radius: 999px; padding: 7px 14px; cursor: pointer;
}
.icon-btn:hover { color: var(--ink); border-color: var(--accent); }

.progress-bar-outer {
  height: 8px; background: var(--surface-2); border-radius: 999px; overflow: hidden; margin: 4px 0 18px;
}
.progress-bar-inner { height: 100%; background: var(--accent); border-radius: 999px; transition: width .3s ease; }
.progress-label { font-family: var(--font-mono); font-size: 12px; color: var(--ink-muted); margin-bottom: 10px; }

.card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px; margin-bottom: 16px;
}

.section-title {
  font-size: 13px; font-family: var(--font-mono); text-transform: uppercase; letter-spacing: .05em;
  color: var(--ink-muted); margin: 26px 0 12px; padding-top: 10px; border-top: 1px solid var(--border);
}
.section-title:first-of-type { margin-top: 0; padding-top: 0; border-top: none; }

.challenge-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 14px; }
.challenge-card {
  text-align: left; cursor: pointer; background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 0; overflow: hidden; display: flex; flex-direction: column;
  font-family: var(--font-body); color: var(--ink); transition: border-color .15s, transform .1s;
}
.challenge-card:hover { border-color: var(--accent); }
.challenge-card:active { transform: translateY(1px); }
.belt-stripe { height: 8px; }
.challenge-card-body { padding: 14px 16px 16px; flex: 1; display: flex; flex-direction: column; gap: 8px; }
.challenge-card-top { display: flex; justify-content: space-between; align-items: flex-start; gap: 8px; }
.challenge-num { font-family: var(--font-mono); font-size: 11px; color: var(--ink-muted); }
.belt-tag {
  font-family: var(--font-mono); font-size: 10.5px; padding: 2px 8px; border-radius: 999px; font-weight: 700;
  white-space: nowrap;
}
.challenge-title { font-size: 15px; font-weight: 600; font-family: var(--font-body); }
.challenge-teaser { font-size: 12.8px; color: var(--ink-muted); flex: 1; }
.done-badge {
  font-family: var(--font-mono); font-size: 11.5px; color: var(--success); display: flex; align-items: center; gap: 4px;
}

.completion-banner {
  background: var(--belt-final); color: #f1d98b; border-radius: var(--radius); padding: 22px;
  text-align: center; margin-bottom: 16px;
}
.completion-banner h2 { color: #f1d98b; font-size: 18px; margin-bottom: 6px; }
.completion-banner .code {
  display: inline-block; margin-top: 10px; background: #00000055; padding: 6px 14px; border-radius: 8px;
  font-family: var(--font-mono); letter-spacing: .04em; font-size: 13px;
}

.back-link {
  display: inline-flex; align-items: center; gap: 6px; font-family: var(--font-mono); font-size: 12.5px;
  color: var(--ink-muted); background: none; border: none; cursor: pointer; margin-bottom: 14px; padding: 0;
}
.back-link:hover { color: var(--accent); }

.challenge-header { display: flex; align-items: center; gap: 10px; margin-bottom: 4px; flex-wrap: wrap; }
.challenge-header h2 { font-size: 19px; font-family: var(--font-body); font-weight: 700; }

.story { font-size: 13.8px; color: var(--ink-muted); margin: 10px 0 16px; }

details.context { margin-bottom: 14px; border: 1px solid var(--border); border-radius: 8px; overflow: hidden; }
details.context summary {
  cursor: pointer; padding: 9px 12px; font-family: var(--font-mono); font-size: 12px; background: var(--surface-2);
  list-style: none; color: var(--ink-muted);
}
details.context summary::-webkit-details-marker { display: none; }
details.context summary::before { content: "▸ "; color: var(--accent); }
details.context[open] summary::before { content: "▾ "; }
.context-body { padding: 12px; display: flex; gap: 12px; flex-wrap: wrap; }
.context-col { flex: 1 1 220px; min-width: 0; }
.context-col .label {
  font-family: var(--font-mono); font-size: 10.5px; text-transform: uppercase; letter-spacing: .05em;
  color: var(--ink-muted); margin-bottom: 4px;
}

.code-panel {
  background: var(--code-bg); color: var(--code-ink); border-radius: 8px; overflow: hidden;
  font-family: var(--font-mono); font-size: 12.6px;
}
.code-panel pre { margin: 0; padding: 10px 12px; white-space: pre-wrap; word-break: break-word; overflow-x: auto; }

textarea.resolve-editor {
  width: 100%; min-height: 190px; background: var(--code-bg); color: var(--code-ink);
  font-family: var(--font-mono); font-size: 12.8px; border: 1px solid var(--border); border-radius: 8px;
  padding: 12px; resize: vertical;
}
textarea.resolve-editor:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }

.btnrow { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }
button.action {
  font-family: var(--font-mono); font-size: 12.6px; font-weight: 500; border: 1px solid var(--border);
  background: var(--surface-2); color: var(--ink); border-radius: 8px; padding: 9px 14px; cursor: pointer;
}
button.action:hover { border-color: var(--accent); }
button.action.primary { background: var(--accent); color: var(--accent-ink); border-color: var(--accent); }
button.action.ghost { background: none; }

.choice-list { display: flex; flex-direction: column; gap: 8px; margin-top: 14px; }
.choice-btn {
  text-align: left; font-family: var(--font-body); font-size: 13.6px; padding: 12px 14px;
  border: 1px solid var(--border); background: var(--surface); color: var(--ink); border-radius: 8px; cursor: pointer;
}
.choice-btn:hover { border-color: var(--accent); }
.choice-btn.correct { border-color: var(--success); background: var(--success-bg); }
.choice-btn.incorrect { border-color: var(--danger); background: var(--danger-bg); }

.feedback {
  font-size: 13.4px; padding: 12px 14px; border-radius: 8px; margin-top: 14px; display: flex; gap: 10px;
}
.feedback[hidden] { display: none; }
.feedback.ok { background: var(--success-bg); color: var(--success); }
.feedback.err { background: var(--danger-bg); color: var(--danger); }
.feedback .icon { font-size: 16px; line-height: 1; }

.hint-box {
  margin-top: 14px; border: 1px dashed var(--border); border-radius: 8px; padding: 12px 14px; font-size: 13px;
}
.hint-box .hint-title { font-family: var(--font-mono); font-size: 11px; text-transform: uppercase; color: var(--ink-muted); margin-bottom: 6px; }
.hint-list { margin: 0; padding-left: 18px; }
.hint-list li { margin-bottom: 6px; color: var(--ink); }

/* modal */
.modal-overlay {
  position: fixed; inset: 0; background: rgba(20, 16, 12, .5); display: flex; align-items: center;
  justify-content: center; padding: 20px; z-index: 50;
}
.modal-overlay[hidden] { display: none; }
.modal {
  background: var(--surface); border-radius: var(--radius); max-width: 640px; width: 100%;
  max-height: 85vh; overflow-y: auto; padding: 22px 24px; border: 1px solid var(--border);
}
.modal h2 { font-size: 17px; margin-bottom: 4px; }
.modal .close-modal {
  float: right; font-family: var(--font-mono); font-size: 12px; border: 1px solid var(--border);
  background: var(--surface-2); border-radius: 999px; padding: 5px 12px; cursor: pointer; color: var(--ink-muted);
}
.help-section { margin-top: 16px; }
.help-section h3 { font-size: 13px; margin-bottom: 6px; }
.help-section p, .help-section li { font-size: 13px; color: var(--ink-muted); }
.marker-example { margin: 8px 0; }
table.cmds { width: 100%; border-collapse: collapse; font-size: 12.6px; margin-top: 6px; }
table.cmds td { padding: 4px 0; border-top: 1px solid var(--border); vertical-align: top; }
table.cmds td.cmdcol { font-family: var(--font-mono); white-space: nowrap; padding-right: 10px; }
table.cmds td.desc { color: var(--ink-muted); }

footer.note { margin-top: 22px; font-size: 12px; color: var(--ink-muted); text-align: center; }

/* rebase board */
.rebase-palette { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; margin-bottom: 10px; }
.rebase-palette-label { font-size: 12.6px; color: var(--ink-muted); margin-right: 4px; }
.action-chip {
  font-family: var(--font-mono); font-size: 12.6px; font-weight: 600; padding: 7px 14px; border-radius: 999px;
  cursor: grab; border: 1px solid transparent; user-select: none;
}
.action-chip:active { cursor: grabbing; }
.chip-pick { background: var(--surface-2); color: var(--ink); border-color: var(--border); }
.chip-squash { background: var(--warn-bg); color: var(--warn); border-color: var(--warn); }
.chip-drop { background: var(--danger-bg); color: var(--danger); border-color: var(--danger); }

.rebase-legend { display: flex; flex-wrap: wrap; gap: 14px; font-size: 12px; color: var(--ink-muted); margin-bottom: 16px; }
.rebase-legend b { font-family: var(--font-mono); }
.rebase-legend b.action-pick { color: var(--ink); }
.rebase-legend b.action-squash { color: var(--warn); }
.rebase-legend b.action-drop { color: var(--danger); }

.rebase-list { display: flex; flex-direction: column; gap: 8px; }
.rebase-row {
  display: flex; align-items: center; gap: 12px; padding: 10px 12px; background: var(--surface-2);
  border: 1px solid var(--border); border-radius: 8px; flex-wrap: wrap;
}
.rebase-hash { font-size: 12px; color: var(--ink-muted); }
.rebase-message { flex: 1; min-width: 160px; font-size: 13.4px; }
.rebase-dropzone {
  font-family: var(--font-mono); font-size: 12.6px; font-weight: 600; padding: 7px 16px; border-radius: 999px;
  border: 2px dashed var(--border); cursor: pointer; min-width: 74px; text-align: center; user-select: none;
  transition: border-color .12s, background .12s;
}
.rebase-dropzone.action-pick { background: var(--surface); color: var(--ink); }
.rebase-dropzone.action-squash { background: var(--warn-bg); color: var(--warn); border-style: solid; border-color: var(--warn); }
.rebase-dropzone.action-drop { background: var(--danger-bg); color: var(--danger); border-style: solid; border-color: var(--danger); }
.rebase-dropzone.drag-over { border-color: var(--accent); }

/* name gate */
.name-gate-overlay {
  position: fixed; inset: 0; background: var(--bg); display: flex; align-items: center;
  justify-content: center; padding: 20px; z-index: 60;
}
.name-gate-overlay[hidden] { display: none; }
.name-gate-card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 28px; max-width: 420px; width: 100%; text-align: center;
}
.name-gate-card h2 { font-size: 18px; margin-bottom: 8px; }
.name-gate-card p { font-size: 13px; color: var(--ink-muted); margin-bottom: 16px; }
.name-gate-card input[type="text"] {
  width: 100%; font-family: var(--font-body); font-size: 14px; padding: 10px 12px;
  border: 1px solid var(--border); border-radius: 8px; background: var(--surface-2); color: var(--ink);
  margin-bottom: 12px;
}
.student-badge {
  font-family: var(--font-mono); font-size: 12px; color: var(--ink-muted); display: flex;
  align-items: center; gap: 8px;
}
.student-badge[hidden] { display: none; }
.student-badge button { font: inherit; }

/* admin */
.admin-password-input {
  font-family: var(--font-body); font-size: 14px; padding: 9px 12px; border: 1px solid var(--border);
  border-radius: 8px; background: var(--surface-2); color: var(--ink); width: 220px; max-width: 100%;
}
table.admin-table { width: 100%; border-collapse: collapse; font-size: 13px; }
table.admin-table th, table.admin-table td {
  padding: 9px 12px; text-align: left; border-bottom: 1px solid var(--border); white-space: nowrap;
}
table.admin-table thead th {
  font-family: var(--font-mono); font-size: 11px; text-transform: uppercase; letter-spacing: .04em;
  color: var(--ink-muted); background: var(--surface-2);
}
table.admin-table td.cell-center, table.admin-table th.cell-center { text-align: center; }
.check-yes { color: var(--success); font-weight: 700; }
.check-no { color: var(--ink-muted); }