:root {
  --bg: #0d1117;
  --panel: #161b22;
  --panel-2: #1c2230;
  --border: #2a3140;
  --text: #e6edf3;
  --muted: #9aa7b4;
  --accent: #5b9dff;
  --accent-2: #7c5cff;
  --green: #3fb950;
  --radius: 12px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: radial-gradient(1200px 600px at 50% -10%, #182233 0%, var(--bg) 60%);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}

.app {
  max-width: 860px;
  margin: 0 auto;
  padding: 48px 20px 80px;
  /* Sticky footer: fill at least the viewport so .foot can sit at the bottom. */
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Hero */
.hero { text-align: center; margin-bottom: 28px; }
.hero h1 {
  font-size: 34px;
  margin: 0 0 6px;
  letter-spacing: -0.5px;
}
.logo {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.subtitle { color: var(--muted); margin: 0; font-size: 15px; }
.stats { color: var(--accent); }

/* Search bar */
.searchbar {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.35);
}
.input-row { display: flex; gap: 10px; }
.input-row input {
  flex: 1;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 14px 16px;
  color: var(--text);
  font-size: 16px;
  outline: none;
  transition: border-color 0.15s;
}
.input-row input:focus { border-color: var(--accent); }
.input-row button {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff;
  border: 0;
  border-radius: 10px;
  padding: 0 22px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.05s, opacity 0.15s;
}
.input-row button:hover { opacity: 0.92; }
.input-row button:active { transform: translateY(1px); }
.input-row button:disabled { opacity: 0.6; cursor: default; }

/* Example chips */
.examples { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }
.chip {
  background: var(--panel-2);
  border: 1px solid var(--border);
  color: var(--muted);
  border-radius: 999px;
  padding: 6px 12px;
  font-size: 13px;
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s;
}
.chip:hover { color: var(--text); border-color: var(--accent); }

/* Controls */
.controls {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
}
.methods { display: flex; flex-wrap: wrap; gap: 6px; }
.method {
  background: var(--panel-2);
  border: 1px solid var(--border);
  color: var(--muted);
  border-radius: 8px;
  padding: 7px 12px;
  font-size: 13px;
  cursor: pointer;
  transition: all 0.15s;
}
.method:hover:not(:disabled) { color: var(--text); }
.method.active {
  background: rgba(91, 157, 255, 0.16);
  border-color: var(--accent);
  color: var(--accent);
}
.method:disabled { opacity: 0.4; cursor: not-allowed; }

.filters { display: flex; gap: 14px; }
.filters label {
  display: flex;
  flex-direction: column;
  font-size: 11px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  gap: 4px;
}
.filters select {
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 8px;
  padding: 6px 8px;
  font-size: 14px;
}

/* Error */
.error {
  margin-top: 18px;
  background: rgba(248, 81, 73, 0.12);
  border: 1px solid rgba(248, 81, 73, 0.4);
  color: #ff8b82;
  padding: 12px 16px;
  border-radius: 10px;
}

/* Results */
.results { margin-top: 26px; }
.results-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--muted);
  font-size: 14px;
  margin-bottom: 12px;
}
.timing {
  font-variant-numeric: tabular-nums;
  background: var(--panel-2);
  border: 1px solid var(--border);
  padding: 4px 10px;
  border-radius: 999px;
  font-size: 12px;
}
.expansion {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  margin-bottom: 16px;
}
.exp-label { color: var(--muted); font-size: 13px; }
.exp-term {
  background: rgba(124, 92, 255, 0.16);
  border: 1px solid rgba(124, 92, 255, 0.4);
  color: #c4b5ff;
  border-radius: 999px;
  padding: 3px 10px;
  font-size: 12px;
}

.empty { color: var(--muted); padding: 24px; text-align: center; }

.cards { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 12px; }
.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 18px;
  transition: border-color 0.15s, transform 0.05s;
}
.card:hover { border-color: var(--accent); }
.card-head { display: flex; gap: 10px; align-items: baseline; }
.rank { color: var(--muted); font-size: 13px; font-variant-numeric: tabular-nums; min-width: 28px; }
.headline {
  color: var(--text);
  font-size: 16px;
  font-weight: 600;
  text-decoration: none;
  line-height: 1.35;
}
.headline:hover { color: var(--accent); text-decoration: underline; }
.desc { color: var(--muted); font-size: 14px; line-height: 1.5; margin: 8px 0 10px 38px; }
.card-foot {
  display: flex;
  gap: 14px;
  align-items: center;
  margin-left: 38px;
  font-size: 12px;
}
.cat {
  background: rgba(63, 185, 80, 0.14);
  color: var(--green);
  border-radius: 6px;
  padding: 2px 8px;
  font-weight: 600;
  letter-spacing: 0.3px;
}
.date { color: var(--muted); }
.score { color: var(--muted); margin-left: auto; font-variant-numeric: tabular-nums; }

/* Relevance feedback */
.fb-hint {
  margin: 12px 0 0;
  font-size: 13px;
  color: var(--muted);
}
.feedback-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin: 4px 0 16px;
  padding: 10px 14px;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 13px;
  color: var(--muted);
}
.feedback-bar button {
  padding: 7px 14px;
  border: 0;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  font-weight: 600;
  cursor: pointer;
}
.feedback-bar button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}
.relevant-check {
  width: 16px;
  height: 16px;
  margin-right: 4px;
  accent-color: var(--accent);
  cursor: pointer;
}
.card.marked {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent) inset;
}

.foot {
  /* Push to the bottom of the page; keeps spacing from content when the page
     is long, but pins to the viewport bottom when content is short. */
  margin-top: auto;
  padding-top: 48px;
  text-align: center;
  color: var(--muted);
  font-size: 12px;
}

/* ---- Mobile ---- */
@media (max-width: 640px) {
  .app { padding: 28px 16px 56px; }
  .hero { margin-bottom: 22px; }
  .hero h1 { font-size: 27px; }
  .subtitle { font-size: 14px; }
  .searchbar { padding: 14px; }

  /* stack methods over the filters, and let filters fill the width */
  .controls { flex-direction: column; }
  .filters { width: 100%; }
  .filters label { flex: 1; }
  .filters select { width: 100%; }

  /* wrap instead of overflowing on narrow screens */
  .results-meta { flex-wrap: wrap; gap: 6px; }
  .card-foot { flex-wrap: wrap; gap: 8px 12px; }
  .desc, .card-foot { margin-left: 0; }
  .feedback-bar { flex-wrap: wrap; }
}

@media (max-width: 380px) {
  .hero h1 { font-size: 24px; }
  /* stack the search input and button so both are full-width, thumb-friendly */
  .input-row { flex-direction: column; }
  .input-row button { padding: 12px; }
  .method { padding: 6px 10px; font-size: 12px; }
}