@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;600;700&display=swap');

:root {
  --bg: radial-gradient(circle at 20% 20%, #363018 0, #1a120d 45%, #160e0a 100%);
  --panel: rgba(255, 255, 255, 0.04);
  --border: rgba(255, 255, 255, 0.08);
  --text: #e9edf3;
  --muted: #babc9a;
  --accent: #f37272;
  --accent-strong: #d33a3a;
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: 'Space Grotesk', 'Segoe UI', sans-serif;
  background: var(--bg);
  color: var(--text);
  display: flex;
  justify-content: center;
  padding: 16px;
}

.app {
  width: min(900px, 100%);
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.hero {
  background: linear-gradient(135deg, rgba(114, 243, 200, 0.14), rgba(58, 211, 211, 0.08));
  border-radius: 18px;
  padding: 16px 14px;
  border: 1px solid var(--border);
}

.hero h1 {
  margin: 4px 0;
  letter-spacing: -0.02em;
}

.hero .lede {
  margin: 6px 0 0;
  color: var(--muted);
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 16px;
}

.panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 10px;
}

h2 {
  margin: 0;
  letter-spacing: -0.015em;
}

.lede {
  color: var(--muted);
}

.pill {
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.08);
  padding: 8px 12px;
  color: var(--muted);
  font-weight: 600;
}

.pill.muted {
  background: rgba(255, 255, 255, 0.06);
}

.field {
  margin: 10px 0;
}

.slider {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.slider-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

input,
button {
  font: inherit;
}

input[type="range"] {
  width: 100%;
  accent-color: var(--accent-strong);
}

.hint {
  text-align: center;
  color: var(--muted);
  font-size: 13px;
  margin: 1;
}

button {
  border: 1px solid var(--border);
  cursor: pointer;
  border-radius: 12px;
  padding: 12px 14px;
  font-weight: 700;
  transition: transform 0.1s ease, background 0.2s ease, border-color 0.2s ease;
}

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

.primary {
  background: linear-gradient(140deg, var(--accent) 0%, var(--accent-strong) 100%);
  color: #0a1b14;
  border-color: rgba(243, 114, 114, 0.3);
}

.mar {
  margin-bottom: 10px;
}

.ghost {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text);
}

.full {
  width: 100%;
}

.card {
  position: relative;
  border-radius: 14px;
  background: linear-gradient(160deg, rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0.02));
  border: 1px solid rgba(255, 255, 255, 0.12);
  min-height: 200px;
  display: grid;
  place-items: center;
  overflow: hidden;
  transform-style: preserve-3d;
  isolation: isolate;
  transition: transform 0.2s ease;
}

.card::after {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 30% 30%, rgba(114, 243, 200, 0.18), transparent 42%);
  pointer-events: none;
}

.card-face {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  font-size: 28px;
  font-weight: 700;
  text-align: center;
  padding: 0 10px;
  z-index: 1;
  backface-visibility: hidden;
  transform: rotateY(0deg);
  transition: transform 0.45s ease, opacity 0.25s ease;
  opacity: 1;
}

.placeholder {
  color: var(--muted);
}

.card .card-face.revealed {
  transform: rotateY(180deg);
  opacity: 0;
}

.card.revealed .placeholder {
  transform: rotateY(-180deg);
  opacity: 0;
}

.card.revealed .card-face.revealed {
  transform: rotateY(0deg);
  opacity: 1;
}

.card.holding {
  transform: rotateX(10deg) scale(1.02);
}

.hidden {
  display: none;
}

@media (max-width: 640px) {
  body {
    padding: 12px;
  }
  .panel-header {
    flex-direction: column;
    align-items: flex-start;
  }
}