/* Problem bank — visual identity ported from the Wordle Lab reference.
   Warm near-black brown, terracotta accent, Fraunces / JetBrains Mono / DM Sans.
   The ONE bold place is the difficulty/rating display (.rating-chip / .level-marker). */

:root {
  --bg: #15110d;
  --bg-grad-1: #1a1611;
  --bg-grad-2: #120e0a;
  --surface: #1f1b16;
  --surface-2: #2a251f;
  --surface-3: #36302a;
  --border: #3a342d;
  --border-strong: #524a40;
  --text: #f3ede2;
  --text-dim: #a89f91;
  --text-faint: #6f675c;
  --green: #6aaa64;
  --green-dim: #4d7848;
  --yellow: #c9b458;
  --yellow-dim: #8d7d3d;
  --gray: #4a4540;
  --accent: #e08850;
  --accent-dim: #9d5f38;
  --danger: #c75555;
  --shadow: 0 1px 0 rgba(255, 255, 255, 0.04), 0 4px 24px rgba(0, 0, 0, 0.4);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: radial-gradient(ellipse at top, var(--bg-grad-1), var(--bg-grad-2) 60%, var(--bg));
  background-attachment: fixed;
  color: var(--text);
  font-family: "DM Sans", system-ui, sans-serif;
  font-size: 15px;
  line-height: 1.55;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.012) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.012) 1px, transparent 1px);
  background-size: 48px 48px;
  z-index: 0;
  mix-blend-mode: screen;
}

main {
  position: relative;
  z-index: 1;
  max-width: 1180px;
  margin: 0 auto;
  padding: 56px 32px 96px;
}

a { color: inherit; }

/* ===== Header ===== */
header {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  border-bottom: 1px solid var(--border);
  padding-bottom: 24px;
  margin-bottom: 36px;
  gap: 32px;
  flex-wrap: wrap;
}

.brand {
  font-family: "Fraunces", serif;
  font-variation-settings: "opsz" 144, "wght" 500;
  font-size: clamp(34px, 5vw, 58px);
  letter-spacing: -0.025em;
  line-height: 0.95;
  margin: 0;
  color: var(--text);
  text-decoration: none;
}
.brand .amp {
  color: var(--accent);
  font-style: italic;
  font-variation-settings: "opsz" 144, "wght" 400;
}
.tagline {
  font-family: "JetBrains Mono", monospace;
  font-size: 12px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-faint);
  margin-top: 8px;
}
.meta {
  font-family: "JetBrains Mono", monospace;
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-faint);
  text-align: right;
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-items: flex-end;
}
.meta span { color: var(--accent); }
.meta a { color: var(--text-dim); text-decoration: none; border-bottom: 1px dotted var(--border-strong); }
.meta a:hover { color: var(--accent); }

/* ===== Section heading ===== */
.section-head {
  display: flex;
  align-items: baseline;
  gap: 16px;
  margin-bottom: 18px;
  flex-wrap: wrap;
}
.section-num {
  font-family: "JetBrains Mono", monospace;
  font-size: 11px;
  letter-spacing: 0.15em;
  color: var(--accent);
}
.section-title {
  font-family: "Fraunces", serif;
  font-variation-settings: "opsz" 72, "wght" 500;
  font-size: 26px;
  letter-spacing: -0.015em;
  margin: 0;
}
.section-sub {
  font-family: "JetBrains Mono", monospace;
  font-size: 11px;
  color: var(--text-faint);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

/* ===== Mono label / eyebrow ===== */
.label {
  font-family: "JetBrains Mono", monospace;
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-faint);
  display: block;
  margin-bottom: 6px;
}

/* ===== Panels / cards ===== */
.panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 24px 26px;
  box-shadow: var(--shadow);
  margin-bottom: 28px;
}

/* ===== Inputs ===== */
input[type="text"],
input[type="number"],
input[type="search"],
select,
textarea {
  font-family: "DM Sans", system-ui, sans-serif;
  font-size: 14px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 9px 12px;
  border-radius: 7px;
  outline: none;
  transition: border-color 0.1s, background 0.1s;
  width: 100%;
}
input:focus, select:focus, textarea:focus {
  border-color: var(--accent);
  background: var(--surface-3);
}
input.invalid, select.invalid, textarea.invalid { border-color: var(--danger); }
textarea {
  resize: vertical;
  line-height: 1.55;
  min-height: 120px;
}
.mono-input {
  font-family: "JetBrains Mono", monospace;
  letter-spacing: 0.02em;
}
select {
  appearance: none;
  background-image: linear-gradient(45deg, transparent 50%, var(--text-faint) 50%),
    linear-gradient(135deg, var(--text-faint) 50%, transparent 50%);
  background-position: calc(100% - 16px) 50%, calc(100% - 11px) 50%;
  background-size: 5px 5px, 5px 5px;
  background-repeat: no-repeat;
  padding-right: 30px;
}

/* ===== Buttons ===== */
.btn {
  font-family: "JetBrains Mono", monospace;
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 10px 18px;
  border-radius: 7px;
  cursor: pointer;
  transition: all 0.12s;
  border: 1px solid var(--border-strong);
  background: var(--surface-2);
  color: var(--text);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.btn:hover { border-color: var(--accent-dim); background: var(--surface-3); }
.btn.primary {
  background: linear-gradient(180deg, var(--accent), var(--accent-dim));
  border-color: var(--accent-dim);
  color: #1a1410;
  font-weight: 700;
}
.btn.primary:hover { filter: brightness(1.07); }
.btn.ghost {
  background: transparent;
  border-style: dashed;
  color: var(--text-dim);
}
.btn.ghost:hover { color: var(--accent); border-color: var(--accent-dim); }
.btn.danger:hover { border-color: var(--danger); color: var(--danger); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

/* ===== Filter bar ===== */
.filters {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}
@media (max-width: 820px) { .filters { grid-template-columns: 1fr; } }
.field { margin-bottom: 14px; }
.field:last-child { margin-bottom: 0; }

.range-row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.range-row input[type="number"] { width: 90px; }
.range-sep { color: var(--text-faint); font-family: "JetBrains Mono", monospace; }

/* chips (multi-select toggles) */
.chips { display: flex; flex-wrap: wrap; gap: 6px; }
.chip {
  font-family: "JetBrains Mono", monospace;
  font-size: 11px;
  letter-spacing: 0.05em;
  padding: 5px 11px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text-dim);
  cursor: pointer;
  transition: all 0.12s;
  user-select: none;
}
.chip:hover { border-color: var(--accent-dim); color: var(--text); }
.chip.on { background: var(--accent); border-color: var(--accent); color: #1a1410; font-weight: 700; }
.chip.tiny { font-size: 10px; padding: 3px 9px; }

/* tag autocomplete helper */
.tag-helper { position: relative; }
.tag-cloud {
  display: flex; flex-wrap: wrap; gap: 6px;
  max-height: 132px; overflow-y: auto;
  margin-top: 8px; padding: 4px;
}
.tag-cloud .chip { cursor: pointer; }

.inline-error {
  margin-top: 8px;
  font-family: "JetBrains Mono", monospace;
  font-size: 12px;
  color: var(--danger);
  line-height: 1.5;
}
.inline-hint {
  margin-top: 6px;
  font-size: 12px;
  color: var(--text-faint);
}

/* ===== Results ===== */
.results-head {
  display: flex; justify-content: space-between; align-items: baseline;
  margin: 8px 0 18px; flex-wrap: wrap; gap: 12px;
}
.count {
  font-family: "JetBrains Mono", monospace;
  font-size: 11px; letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--text-faint);
}
.count b { color: var(--accent); }

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 18px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px 22px;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  gap: 12px;
  transition: border-color 0.15s, transform 0.05s;
  cursor: pointer;
  text-decoration: none;
  color: inherit;
}
.card:hover { border-color: var(--border-strong); }
.card:active { transform: scale(0.997); }
.card-top { display: flex; justify-content: space-between; align-items: flex-start; gap: 12px; }
.card-name {
  font-family: "Fraunces", serif;
  font-variation-settings: "opsz" 36, "wght" 500;
  font-size: 20px;
  letter-spacing: -0.01em;
  margin: 0;
  line-height: 1.15;
}
.card-excerpt {
  font-size: 13px;
  color: var(--text-dim);
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.card-tags { display: flex; flex-wrap: wrap; gap: 5px; }
.tag-pill {
  font-family: "JetBrains Mono", monospace;
  font-size: 10px;
  letter-spacing: 0.04em;
  padding: 2px 8px;
  border-radius: 4px;
  background: var(--surface-2);
  color: var(--text-dim);
  border: 1px solid var(--border);
}
.card-foot {
  display: flex; align-items: center; gap: 10px; flex-wrap: wrap;
  margin-top: 2px;
}

/* ===== Signature: difficulty display ===== */
.rating-chip {
  font-family: "JetBrains Mono", monospace;
  font-weight: 700;
  font-size: 13px;
  letter-spacing: 0.02em;
  padding: 5px 11px 5px 9px;
  border-radius: 7px;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  background: var(--surface-2);
  border: 1px solid var(--border-strong);
  color: var(--text);
  white-space: nowrap;
}
.rating-chip::before {
  content: "";
  width: 9px; height: 9px; border-radius: 50%;
  background: var(--rating-color, var(--text-faint));
  box-shadow: 0 0 0 2px color-mix(in srgb, var(--rating-color, var(--text-faint)) 30%, transparent);
}
.rating-chip.unrated { color: var(--text-faint); }
.rating-chip .num { font-size: 14px; }

/* Codeforces-ish rating bands as a dot colour */
.r-gray   { --rating-color: #9b9b9b; }
.r-green  { --rating-color: #4aa14a; }
.r-cyan   { --rating-color: #45b3b3; }
.r-blue   { --rating-color: #5b8def; }
.r-purple { --rating-color: #b05bd6; }
.r-orange { --rating-color: #e08850; }
.r-red    { --rating-color: #d05656; }

.level-marker {
  font-family: "JetBrains Mono", monospace;
  font-weight: 700;
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 5px 10px;
  border-radius: 7px;
  border: 1px solid var(--accent-dim);
  color: var(--accent);
  background: linear-gradient(180deg, rgba(224, 136, 80, 0.12), rgba(224, 136, 80, 0.02));
  white-space: nowrap;
}
.level-marker .lv-lab { color: var(--text-faint); font-weight: 400; margin-right: 6px; }

/* ===== Status badges ===== */
.status-badge {
  font-family: "JetBrains Mono", monospace;
  font-size: 10px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 4px 9px;
  border-radius: 999px;
  border: 1px solid transparent;
  white-space: nowrap;
}
.status-unused   { color: var(--green);  border-color: var(--green-dim);  background: rgba(106, 170, 100, 0.08); }
.status-reserved { color: var(--yellow); border-color: var(--yellow-dim); background: rgba(201, 180, 88, 0.08); }
.status-used     { color: var(--text-faint); border-color: var(--border-strong); background: var(--surface-2); }
.status-draft    { color: var(--accent); border-color: var(--accent-dim); background: rgba(224, 136, 80, 0.08); }

.extra-flag {
  font-family: "JetBrains Mono", monospace;
  font-size: 10px;
  letter-spacing: 0.06em;
  color: var(--text-faint);
}

/* ===== Empty / error states ===== */
.empty-state {
  font-family: "JetBrains Mono", monospace;
  font-size: 13px;
  color: var(--text-faint);
  letter-spacing: 0.04em;
  padding: 40px 8px;
  text-align: center;
  font-style: italic;
}
.help-banner {
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: 8px;
  padding: 14px 18px;
  margin-bottom: 24px;
  font-size: 14px;
  color: var(--text-dim);
  line-height: 1.6;
}
.help-banner strong { color: var(--text); font-weight: 500; }
.help-banner code {
  font-family: "JetBrains Mono", monospace;
  font-size: 12px;
  background: var(--surface-2);
  padding: 1px 6px;
  border-radius: 3px;
  color: var(--accent);
}

/* ===== Validation issue lists ===== */
.issue-list { display: flex; flex-direction: column; gap: 6px; margin-top: 6px; }
.issue {
  display: flex; gap: 10px; align-items: baseline;
  font-size: 13px; padding: 8px 12px; border-radius: 7px;
  background: var(--surface-2); border: 1px solid var(--border);
}
.issue .lvl {
  font-family: "JetBrains Mono", monospace; font-size: 10px;
  letter-spacing: 0.1em; text-transform: uppercase; padding: 2px 7px;
  border-radius: 4px; flex-shrink: 0;
}
.issue.error  { border-left: 3px solid var(--danger); }
.issue.error .lvl  { color: var(--danger); }
.issue.confirm { border-left: 3px solid var(--yellow); }
.issue.confirm .lvl { color: var(--yellow); }
.issue.warn   { border-left: 3px solid var(--accent); }
.issue.warn .lvl  { color: var(--accent); }
.issue .where { font-family: "JetBrains Mono", monospace; font-size: 11px; color: var(--text-faint); }

/* ===== Detail / modal view ===== */
.detail-section { margin-top: 22px; }
.detail-section h3 {
  font-family: "JetBrains Mono", monospace;
  font-size: 11px; letter-spacing: 0.12em; text-transform: uppercase;
  color: var(--accent); margin: 0 0 10px;
}
.prose {
  font-size: 15px; line-height: 1.65; color: var(--text);
  white-space: pre-wrap; word-wrap: break-word;
}
.extra-files-list {
  font-family: "JetBrains Mono", monospace; font-size: 13px;
  color: var(--text-dim); line-height: 1.9;
}
.extra-files-list .f {
  display: inline-block; padding: 1px 8px; margin: 0 4px 4px 0;
  border-radius: 4px; background: var(--surface-2); border: 1px solid var(--border);
}

/* ===== Editor layout ===== */
.editor-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
@media (max-width: 820px) { .editor-grid { grid-template-columns: 1fr; } }
.editor-grid .full { grid-column: 1 / -1; }

.tag-input-row { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; }
.selected-tags { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 8px; min-height: 8px; }
.selected-tags .chip { cursor: default; }
.selected-tags .chip .x { margin-left: 6px; cursor: pointer; color: inherit; opacity: 0.7; }
.selected-tags .chip .x:hover { opacity: 1; }
.selected-tags .chip.unknown { border-style: dashed; border-color: var(--yellow-dim); color: var(--yellow); background: rgba(201, 180, 88, 0.06); }

.toolbar { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; margin-top: 8px; }
.save-state {
  font-family: "JetBrains Mono", monospace; font-size: 11px;
  letter-spacing: 0.06em; text-transform: uppercase; color: var(--text-faint);
}
.save-state.ok { color: var(--green); }
.save-state.err { color: var(--danger); }
.save-state.busy { color: var(--accent); }

/* ===== Footer ===== */
footer {
  margin-top: 56px; padding-top: 24px;
  border-top: 1px solid var(--border);
  font-family: "JetBrains Mono", monospace;
  font-size: 11px; color: var(--text-faint);
  letter-spacing: 0.05em;
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 12px;
}
footer a { color: var(--text-dim); text-decoration: none; border-bottom: 1px dotted var(--border-strong); }
footer a:hover { color: var(--accent); }

/* ===== Modal ===== */
.modal-backdrop {
  position: fixed; inset: 0; z-index: 50;
  background: rgba(8, 6, 4, 0.7);
  display: none; align-items: flex-start; justify-content: center;
  padding: 48px 20px; overflow-y: auto;
}
.modal-backdrop.open { display: flex; }
.modal {
  position: relative; z-index: 51;
  background: var(--surface); border: 1px solid var(--border-strong);
  border-radius: 14px; box-shadow: var(--shadow);
  max-width: 820px; width: 100%; padding: 28px 32px 32px;
}
.modal-close {
  position: absolute; top: 16px; right: 18px;
  background: transparent; border: 1px solid var(--border);
  color: var(--text-faint); width: 30px; height: 30px; border-radius: 7px;
  cursor: pointer; font-size: 16px; line-height: 1;
}
.modal-close:hover { color: var(--danger); border-color: var(--danger); }

/* ===== Accessibility ===== */
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; scroll-behavior: auto !important; }
}