:root {
  --bg: #f4f7fb;
  --panel: #ffffff;
  --text: #1c2430;
  --muted: #697386;
  --accent: #0f766e;
  --accent-2: #0b5f58;
  --danger: #b42318;
  --border: #d8dee8;
  --shadow: 0 10px 28px rgba(26, 36, 53, 0.1);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Segoe UI", Tahoma, sans-serif;
  background: radial-gradient(circle at top left, #ffffff, var(--bg));
  color: var(--text);
}

.container {
  width: min(1100px, 94vw);
  margin: 0 auto;
  padding: 20px 0 36px;
}

h1,
h2,
h3,
p {
  margin: 0;
}

a {
  color: inherit;
}

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

.stack {
  display: grid;
  gap: 14px;
}

.row {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.between {
  justify-content: space-between;
}

.btn {
  border: none;
  border-radius: 10px;
  padding: 10px 14px;
  font-weight: 600;
  cursor: pointer;
  background: #e6edf5;
  color: #123;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.btn:hover {
  filter: brightness(0.97);
}

.btn.primary {
  background: var(--accent);
  color: #fff;
}

.btn.primary:hover {
  background: var(--accent-2);
}

.btn.danger {
  background: var(--danger);
  color: #fff;
}

label {
  font-size: 0.92rem;
  color: var(--muted);
}

input,
select {
  width: 100%;
  padding: 10px;
  border-radius: 9px;
  border: 1px solid var(--border);
  font-size: 1rem;
}

.notice {
  color: var(--muted);
  font-size: 0.92rem;
}

.error {
  color: var(--danger);
  font-size: 0.94rem;
}

.game-header {
  display: grid;
  grid-template-columns: repeat(4, minmax(130px, 1fr));
  gap: 10px;
}

.stat {
  background: #f8fafc;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px;
}

.stat .k {
  font-size: 0.78rem;
  color: var(--muted);
}

.stat .v {
  font-size: 1.15rem;
  font-weight: 700;
  margin-top: 4px;
}

.board {
  --cols: 4;
  display: grid;
  grid-template-columns: repeat(var(--cols), minmax(48px, 1fr));
  gap: 8px;
}

.card {
  position: relative;
  width: 100%;
  aspect-ratio: 3 / 4;
  perspective: 700px;
  border: none;
  background: transparent;
  padding: 0;
  cursor: pointer;
}

.card[disabled] {
  cursor: default;
}

.card-inner {
  position: absolute;
  inset: 0;
  border-radius: 10px;
  transform-style: preserve-3d;
  transition: transform 0.35s ease;
  border: 1px solid var(--border);
}

.card.flipped .card-inner,
.card.matched .card-inner {
  transform: rotateY(180deg);
}

.card-face {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  border-radius: 10px;
  backface-visibility: hidden;
}

.card-front {
  background: #fff;
  transform: rotateY(180deg);
}

.card-back {
  background: linear-gradient(135deg, #0f766e, #115e59);
  color: #fff;
  font-weight: 700;
}

.card img {
  width: 85%;
  height: 85%;
  object-fit: contain;
}

.card.matched {
  opacity: 0.72;
}

.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

@media (max-width: 860px) {
  .game-header {
    grid-template-columns: repeat(2, minmax(130px, 1fr));
  }

  .grid-2 {
    grid-template-columns: 1fr;
  }
}