:root {
  --color-background-light-pink: #ffe0f0;
  --color-text: #333;
  --color-game-container-bg: white;
  --color-game-container-shadow: rgba(0, 0, 0, 0.1);
  --color-board-bg: #ffefff;
  --color-board-border: #ffccff;
  --color-grid-lines: #ff99ff;
  --color-intersection-hover: rgba(255, 192, 203, 0.3);
  --color-heart-pink: #FFB6C1;
  --color-last-move-glow: rgba(255, 255, 0, 0.7);
  --color-black: #000;
  --color-white: #fff;
  --color-success-purple: #e0b0ff;
}

body {
  font-family: Arial, sans-serif;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  margin: 0;
  background-color: var(--color-background-light-pink);
  color: var(--color-text);
}

#game-container {
  background-color: var(--color-game-container-bg);
  padding: 20px;
  border-radius: 12px;
  box-shadow: 0 0 20px var(--color-game-container-shadow);
  text-align: center;
}

.game-board-grid {
  position: relative;
  width: calc(14 * 30px);
  height: calc(14 * 30px);
  margin-top: 20px;
  background-color: var(--color-board-bg);
  border: 2px solid var(--color-board-border);
}

.game-board-grid::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image:
    linear-gradient(to right, var(--color-grid-lines) 1px, transparent 1px),
    linear-gradient(to bottom, var(--color-grid-lines) 1px, transparent 1px);
  background-size: 30px 30px;
  background-position: -1px -1px;
  pointer-events: none;
}

.intersection {
  position: absolute;
  width: 30px;
  height: 30px;
  margin-left: -15px;
  margin-top: -15px;
  display: flex;
  justify-content: center;
  align-items: center;
  cursor: pointer;
  z-index: 1;
}

.intersection:hover {
  background-color: var(--color-intersection-hover);
}

.stone-black-heart, .stone-white-heart {
  position: relative;
  width: 24px;
  height: 24px;
  margin: auto;
  overflow: hidden;
}

.stone-black-heart::before,
.stone-black-heart::after,
.stone-white-heart::before,
.stone-white-heart::after {
  content: '';
  position: absolute;
  width: 12px;
  height: 20px;
  border-radius: 50% 50% 0 0;
  border: 1px solid var(--color-black);
  box-sizing: border-box;
  transform: rotate(-45deg);
  transform-origin: 0 100%;
  top: 0;
  left: 12px;
}

.stone-black-heart::after,
.stone-white-heart::after {
  left: 0;
  transform: rotate(45deg);
  transform-origin: 100% 100%;
}

.stone-black-heart::before, .stone-black-heart::after {
  background-color: var(--color-heart-pink);
}

.stone-white-heart::before, .stone-white-heart::after {
  background-color: var(--color-white);
}

.last-move {
  box-shadow: 0 0 5px 3px var(--color-last-move-glow);
}

#messages {
  margin-top: 10px;
  font-size: 0.9em;
  color: var(--color-text);
}

#title-box {
  font-weight: bold;
  color: var(--color-text);
}

#game-link-container {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 40px;
  margin-top: 20px;
}

#copy-link-button {
  position: absolute;
  display: flex;
  justify-content: center;
  align-items: center;
  transition: opacity 0.3s ease;
  padding: 8px 15px;
  border-radius: 5px;
  white-space: nowrap;
}

#copy-link-button {
  background-color: var(--color-board-border);
  color: var(--color-text);
  border: none;
  cursor: pointer;
  gap: 8px;
  font-size: 1em;
}

#copy-link-button:hover {
  background-color: var(--color-grid-lines);
}

#copy-link-button.copied-state {
  background-color: var(--color-success-purple);
}

img.icon {
  width: 1em;
  height: 1em;
  vertical-align: middle;
}