:root {
  --bg: #ffffff;
  --card: #f5f5f5;
  --text: #111111;
  --accent: #000000;
}

body.dark {
  --bg: #0e0e0e;
  --card: #1b1b1b;
  --text: #f2f2f2;
  --accent: #ffffff;
}

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background: var(--bg);
  color: var(--text);
}

header {
  padding: 16px 24px;
  border-bottom: 2px solid var(--accent);
  font-size: 22px;
  font-weight: bold;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.theme-btn {
  background: transparent;
  border: none;
  cursor: pointer;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.theme-btn svg {
  width: 24px;
  height: 24px;
  fill: var(--text);
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 20px;
  padding: 24px;
}

.card {
  background: var(--card);
  border: 2px solid var(--accent);
  border-radius: 12px;
  overflow: hidden;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.15s;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 6px 14px rgba(0, 0, 0, 0.25);
}

.card img {
  width: 100%;
  height: 140px;
  object-fit: cover;
}

.card-title {
  padding: 10px 12px;
  font-weight: bold;
  border-top: 2px solid var(--accent);
}

.ad-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 9999;
}

.ad-box {
  background: var(--bg);
  color: var(--text);
  padding: 20px;
  border-radius: 12px;
  width: 320px;
  text-align: center;
  border: 3px solid var(--accent);
}

.ad-box button {
  margin-top: 12px;
  padding: 8px 14px;
  border: none;
  background: var(--accent);
  color: var(--bg);
  border-radius: 6px;
  cursor: pointer;
}