:root {
  --ink: #202224;
  --paper: #f9f7f0;
  --wood: #6e4429;
  --wood-dark: #402515;
  --field: #15805a;
  --line: #0d5a40;
  --hint: #f2c84b;
  --shadow: rgba(28, 20, 10, .28);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at 20% 8%, rgba(255,255,255,.9), transparent 28%),
    linear-gradient(145deg, #d8e3d9 0%, #f0eadb 48%, #d2c1a8 100%);
  color: var(--ink);
  font-family: "Hiragino Sans", "Yu Gothic", sans-serif;
}

.wrap {
  max-width: 590px;
  margin: 24px auto;
  padding: 0 16px 24px;
}

.top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

h1 {
  margin: 0;
  font-size: 32px;
  letter-spacing: .08em;
  text-shadow: 0 1px 0 rgba(255,255,255,.8);
}

.status, .score {
  margin: 12px 0;
  padding: 10px 12px;
  border-left: 5px solid var(--field);
  border-radius: 0 8px 8px 0;
  background: rgba(255,255,255,.76);
  box-shadow: 0 8px 18px rgba(50, 42, 30, .08);
}

.panel {
  padding: 18px;
  border: 10px solid var(--wood);
  border-radius: 8px;
  background:
    linear-gradient(135deg, rgba(255,255,255,.18), transparent 28%),
    repeating-linear-gradient(90deg, #8a5835 0 18px, var(--wood) 18px 36px);
  box-shadow: 0 20px 40px var(--shadow), inset 0 0 0 2px var(--wood-dark);
}

.board {
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  border: 3px solid #083826;
  border-radius: 4px;
  background: var(--line);
  overflow: hidden;
  box-shadow: inset 0 0 18px rgba(0,0,0,.42);
}

.cell {
  display: grid;
  place-items: center;
  aspect-ratio: 1 / 1;
  min-width: 0;
  border: 1px solid rgba(8, 56, 38, .9);
  background:
    radial-gradient(circle at 35% 25%, #31a97d, var(--field) 58%, #0c5b41),
    linear-gradient(135deg, rgba(255,255,255,.12), rgba(0,0,0,.14));
  cursor: pointer;
  position: relative;
  box-shadow: inset 0 1px 0 rgba(255,255,255,.18), inset 0 -2px 4px rgba(0,0,0,.24);
}

.cell:hover {
  filter: brightness(1.08);
}

.cell:focus-visible {
  outline: 3px solid #ffe08a;
  outline-offset: -5px;
}

.cell.hint::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  width: 24%;
  aspect-ratio: 1;
  border-radius: 50%;
  background: radial-gradient(circle, #ffe58a, var(--hint));
  box-shadow: 0 0 0 5px rgba(242, 200, 75, .16), 0 0 18px rgba(242, 200, 75, .58);
}

.stone {
  width: 74%;
  aspect-ratio: 1;
  border-radius: 50%;
  position: relative;
  transform: translateY(-1px);
}

.stone::before {
  content: "";
  position: absolute;
  inset: 9% 12% auto auto;
  width: 34%;
  aspect-ratio: 1;
  border-radius: 50%;
  filter: blur(1px);
}

.stone.black {
  background:
    radial-gradient(circle at 33% 24%, #6d747b 0 10%, #202329 40%, #050608 76%),
    linear-gradient(145deg, #30343a, #050608);
  box-shadow: inset -9px -10px 15px #000, inset 5px 5px 10px rgba(255,255,255,.08), 0 6px 11px rgba(0,0,0,.48);
}

.stone.black::before {
  background: rgba(255,255,255,.23);
}

.stone.white {
  background:
    radial-gradient(circle at 31% 23%, #fff 0 16%, #f1eadf 48%, #c7bba7 82%),
    linear-gradient(145deg, #fff, #cfc2af);
  box-shadow: inset -8px -9px 14px #b4aa99, inset 5px 5px 11px rgba(255,255,255,.72), 0 6px 11px rgba(0,0,0,.34);
}

.stone.white::before {
  background: rgba(255,255,255,.9);
}

#restart {
  padding: 9px 14px;
  border: none;
  border-radius: 8px;
  background: linear-gradient(180deg, #226e58, #164636);
  color: #fff;
  cursor: pointer;
  box-shadow: 0 7px 14px rgba(22, 70, 54, .28);
}

#restart:hover {
  background: linear-gradient(180deg, #287f66, #194f3d);
}

@media (max-width: 520px) {
  .wrap { margin-top: 14px; padding-inline: 10px; }
  h1 { font-size: 25px; }
  .panel { padding: 10px; border-width: 7px; }
  .status, .score { font-size: 14px; }
}