:root {
  --color-bg: #ffffff;
  --color-surface: #f4f4f7;
  --color-border: #dcdce3;
  --color-text: #0a0a0c;
  --color-text-muted: #54545e;
  --color-accent: #7c3aed;
  --color-accent-contrast: #ffffff;
  --radius: 4px;
  --space-1: 0.5rem;
  --space-2: 1rem;
  --space-3: 1.5rem;
  --space-4: 2.5rem;
  --font-sans: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-heading: "Space Grotesk", var(--font-sans);
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --color-bg: #09090b;
    --color-surface: #161618;
    --color-border: #2a2a2f;
    --color-text: #f5f5f7;
    --color-text-muted: #a3a3ad;
    --color-accent: #a78bfa;
    --color-accent-contrast: #0a0a0c;
  }
}

:root[data-theme="dark"] {
  --color-bg: #09090b;
  --color-surface: #161618;
  --color-border: #2a2a2f;
  --color-text: #f5f5f7;
  --color-text-muted: #a3a3ad;
  --color-accent: #a78bfa;
  --color-accent-contrast: #0a0a0c;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  line-height: 1.5;
}

a {
  color: var(--color-accent);
}

h1,
h2,
h3 {
  font-family: var(--font-heading);
  font-weight: 700;
  letter-spacing: -0.02em;
}

.site-header {
  border-bottom: 2px solid var(--color-text);
  background: var(--color-bg);
}

.site-header__inner {
  max-width: 960px;
  margin: 0 auto;
  padding: var(--space-2) var(--space-2);
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-2);
  flex-wrap: wrap;
}

.site-title {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  text-decoration: none;
  color: var(--color-text);
}

.site-tagline {
  margin: 0;
  color: var(--color-text-muted);
  font-size: 0.95rem;
}

.breadcrumb {
  font-size: 0.9rem;
}

main {
  max-width: 960px;
  margin: 0 auto;
  padding: var(--space-3) var(--space-2);
}

.site-footer {
  border-top: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-size: 0.85rem;
  text-align: center;
  padding: var(--space-3) var(--space-2);
  margin-top: var(--space-4);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: var(--space-2);
  padding: 0;
  margin: var(--space-3) 0 0;
  list-style: none;
}

.card {
  display: block;
  background: var(--color-surface);
  border-top: 3px solid var(--color-accent);
  border-radius: var(--radius);
  padding: var(--space-2);
  text-decoration: none;
  color: inherit;
  transition: transform 0.15s ease;
}

.card:hover,
.card:focus-visible {
  transform: translateY(-2px);
}

.card h2 {
  margin: 0 0 var(--space-1);
  font-size: 1.05rem;
}

.card p {
  margin: 0;
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

.tool-panel {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: var(--space-3);
}

label {
  display: block;
  font-weight: 600;
  margin-bottom: var(--space-1);
  font-size: 0.9rem;
}

input[type="text"],
input[type="color"] {
  font: inherit;
  padding: 0.5rem;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  background: var(--color-bg);
  color: var(--color-text);
}

button {
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  border: none;
  background: var(--color-accent);
  color: var(--color-accent-contrast);
  border-radius: var(--radius);
  padding: 0.5rem 0.9rem;
}

button:hover {
  filter: brightness(1.1);
}

button:focus-visible,
a:focus-visible,
input:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

.field-error {
  color: #c0392b;
  font-size: 0.85rem;
  margin-top: var(--space-1);
}

.theme-toggle {
  display: flex;
  gap: 2px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 2px;
}

.theme-toggle__btn {
  font: inherit;
  font-weight: 600;
  font-size: 0.8rem;
  cursor: pointer;
  border: none;
  background: transparent;
  color: var(--color-text-muted);
  border-radius: calc(var(--radius) - 2px);
  padding: 0.3rem 0.6rem;
}

.theme-toggle__btn:hover {
  color: var(--color-text);
}

.theme-toggle__btn[aria-pressed="true"] {
  background: var(--color-accent);
  color: var(--color-accent-contrast);
}

@media (max-width: 480px) {
  .site-header__inner {
    flex-direction: column;
    align-items: flex-start;
  }
}