:root {
  --bg: #0f1220;
  --card: #151a2e;
  --text: #e8ecff;
  --muted: #aeb7d9;
  --accent: #6c7cff;
  --cold: #4aa8ff; /* cold  */
  --colder: #1e7fff; /* colder */
  --coldest: #0057d9; /* coldest */
  --warm: #ffb84a; /* warm */
  --hot: #ff6a3d; /* hot  */
  --hottest: #ff2b2b; /* hottest */
  --good: #3ddc81; /* correct */
  --error: #ff477e;
  --ring: 2px solid #3c4270;
  --radius: 16px;
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
  background: radial-gradient(
    1200px 800px at 50% -10%,
    #1a2040 0%,
    #0b0f1d 60%,
    #080b16 100%
  );
  color: var(--text);
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Inter,
    "Helvetica Neue", Arial, "Noto Sans", "Apple Color Emoji", "Segoe UI Emoji",
    "Segoe UI Symbol", sans-serif;
  line-height: 1.4;
}

.container {
  max-width: 760px;
  margin: 24px auto;
  padding: 0 16px;
}

header h1 {
  margin: 24px 0 6px;
  letter-spacing: 0.4px;
}

.sub {
  color: var(--muted);
  margin-top: 0;
}

#game {
  background: linear-gradient(
    180deg,
    rgba(255, 255, 255, 0.03),
    rgba(255, 255, 255, 0.01)
  );
  border: var(--ring);
  border-radius: var(--radius);
  padding: 18px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.35),
    inset 0 1px 0 rgba(255, 255, 255, 0.05);
}

form {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: center;
}

input[type="number"] {
  background: var(--card);
  color: var(--text);
  border: 1px solid #2a2f52;
  border-radius: 12px;
  padding: 12px 14px;
  font-size: 18px;
  width: min(280px, 100%);
  outline: none;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

input[type="number"]:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 4px rgba(108, 124, 255, 0.2);
}

button {
  border: 0;
  border-radius: 12px;
  padding: 12px 16px;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.05s ease, opacity 0.2s ease, box-shadow 0.2s ease;
  background: var(--accent);
  color: #0b0e1a;
  box-shadow: 0 8px 24px rgba(108, 124, 255, 0.35);
}

button:active {
  transform: translateY(1px);
}

button.secondary {
  background: #2a2f52;
  color: var(--text);
  box-shadow: none;
}

.status {
  margin-top: 14px;
}

.feedback {
  font-size: 20px;
  font-weight: 700;
  margin: 12px 0 6px;
}

.meta {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.meta .divider {
  margin: 0 8px;
  opacity: 0.5;
}

.thermo-wrap {
  height: 14px;
  background: #111527;
  border-radius: 999px;
  border: 1px solid #242a4d;
  margin-top: 12px;
  overflow: hidden;
}

.thermo {
  height: 100%;
  width: 0%;
  background: linear-gradient(
    90deg,
    var(--coldest),
    var(--hot),
    var(--hottest)
  );
  transition: width 0.4s ease;
}

.chips {
  list-style: none;
  padding: 0;
  margin: 18px 0 6px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.chips li {
  background: var(--card);
  border: 1px solid #2a2f52;
  color: var(--text);
  border-radius: 999px;
  padding: 8px 12px;
  font-size: 14px;
}

.footer {
  color: var(--muted);
  text-align: center;
  font-size: 14px;
}

/* Temperature feedback color states (extra credit) */
.temp-coldest {
  color: var(--coldest);
}
.temp-colder {
  color: var(--colder);
}
.temp-cold {
  color: var(--cold);
}
.temp-warm {
  color: var(--warm);
}
.temp-hot {
  color: var(--hot);
}
.temp-hottest {
  color: var(--hottest);
}
.temp-correct {
  color: var(--good);
}

.visually-hidden {
  position: absolute !important;
  height: 1px;
  width: 1px;
  overflow: hidden;
  clip: rect(1px, 1px, 1px, 1px);
  white-space: nowrap;
}