* {
  box-sizing: border-box;
}

:root {
  --bg: #0f1115;
  --panel: #171a21;
  --panel-2: #1d212b;
  --border: #2a2f3a;
  --text: #f3f4f6;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);

  font-family:
    Inter,
    system-ui,
    sans-serif;

  padding: 24px;
}

.container {
  max-width: 920px;
  margin: 0 auto;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;

  display: flex;
  gap: 12px;
  align-items: center;

  padding-bottom: 18px;
  margin-bottom: 28px;

  background:
    linear-gradient(
      to bottom,
      var(--bg) 75%,
      transparent
    );
}

h1 {
  margin: 0;
  font-size: 1.4rem;
  font-weight: 650;
  letter-spacing: -0.03em;
  flex: 1;
}

.generate-btn {
  border: none;

  background: white;
  color: black;

  padding: 12px 18px;

  border-radius: 12px;

  font-size: 14px;
  font-weight: 600;

  cursor: pointer;

  transition:
    opacity 0.15s ease,
    transform 0.15s ease;
}

.generate-btn:hover {
  opacity: 0.92;
}

.generate-btn:active {
  transform: scale(0.98);
}

.controls {
  display: flex;
  gap: 10px;
  margin-bottom: 22px;
}

.controls button {
  background: var(--panel);
  color: var(--text);

  border: 1px solid var(--border);

  padding: 10px 14px;

  border-radius: 10px;

  font-size: 14px;

  cursor: pointer;
}

.controls button:hover {
  background: var(--panel-2);
}

.categories {
  display: grid;

  grid-template-columns:
    repeat(auto-fill, minmax(160px, 1fr));

  gap: 12px;
}

.category-item {
  position: relative;
}

.category-item input {
  display: none;
}

.category-item label {
  display: flex;
  align-items: center;
  justify-content: center;

  min-height: 62px;
  padding: 14px;

  text-align: center;

  background: var(--panel);

  border:
    1px solid var(--border);

  border-radius: 14px;

  cursor: pointer;

  transition:
    border-color 0.15s ease,
    background 0.15s ease;

  font-size: 14px;
  font-weight: 500;

  line-height: 1.3;

  word-break: break-word;
}

.category-item label:hover {
  background: var(--panel-2);
}

.category-item input:checked + label {
  border-color: white;
  background: #222734;
}

@media (max-width: 640px) {

  body {
    padding: 16px;
  }

  .topbar {
    flex-direction: column;
    align-items: stretch;
  }

  .generate-btn {
    width: 100%;
  }

  .categories {
    grid-template-columns:
      repeat(2, 1fr);
  }
}