/* === Theme Variables === */
:root {
  --color-bg: #ffffff;
  --color-bg-secondary: #f9fafb;
  --color-text: #1a1a1a;
  --color-text-secondary: #6b7280;
  --color-border: #e5e7eb;
  --color-accent: #2563eb;
  --color-accent-hover: #1d4ed8;
  --color-card-shadow: rgba(0,0,0,0.05);
}

[data-theme="dark"] {
  --color-bg: #111111;
  --color-bg-secondary: #1a1a1a;
  --color-text: #e5e5e5;
  --color-text-secondary: #999999;
  --color-border: #2a2a2a;
  --color-accent: #5b9aff;
  --color-accent-hover: #4a89ee;
  --color-card-shadow: rgba(0,0,0,0.3);
}

/* === Reset & Base === */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  min-height: 100vh;
}

a {
  color: var(--color-accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* === Nav === */
.nav {
  background: var(--color-bg-secondary);
  padding: 0.75rem 1.5rem;
  display: flex;
  align-items: center;
  gap: 1rem;
  border-bottom: 1px solid var(--color-border);
}

.nav__brand {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
}

.nav__link {
  color: var(--color-text-secondary);
  font-size: 0.9rem;
}

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

.nav__spacer {
  flex: 1;
}

.theme-toggle {
  background: none;
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
  padding: 0.3rem 0.5rem;
  border-radius: 6px;
  font-size: 1.1rem;
  cursor: pointer;
  line-height: 1;
}

.theme-toggle:hover {
  background: var(--color-border);
  color: var(--color-text);
}

/* === Layout === */
.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

/* === Typography === */
h1 {
  font-size: 2rem;
  margin-bottom: 0.5rem;
  color: var(--color-text);
}

.section h2 {
  position: sticky;
  top: 0;
  background: var(--color-bg);
  z-index: 10;
  padding: 0.5rem 0;
  font-size: 1.4rem;
  margin-bottom: 1rem;
  color: var(--color-text);
}

/* === Card Grid (front page) === */
.section {
  margin-bottom: 2.5rem;
}

.card-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.card {
  background: var(--color-bg-secondary);
  border-radius: 8px;
  padding: 0.75rem 1rem;
  transition: transform 0.15s, box-shadow 0.15s;
  border: 1px solid var(--color-border);
}

.card:hover {
  transform: translateY(-3px);
  box-shadow: 0 4px 12px var(--color-card-shadow);
  border-color: var(--color-accent);
}

.card {
  cursor: pointer;
}

.card a {
  display: block;
  color: var(--color-text);
  font-weight: 600;
  font-size: 1.1rem;
}

.card a:hover {
  text-decoration: none;
}


/* === App page shared === */
.app-container {
  max-width: 600px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
  text-align: center;
}

.app-container h1 {
  margin-bottom: 1rem;
}

button {
  background: var(--color-accent);
  color: #fff;
  border: none;
  padding: 0.6rem 1.5rem;
  border-radius: 6px;
  font-size: 1rem;
  cursor: pointer;
  transition: background 0.15s;
}

button:hover {
  background: var(--color-accent-hover);
}

input, textarea, select {
  background: var(--color-bg-secondary);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 0.5rem 0.75rem;
  font-size: 1rem;
  width: 100%;
}

input:focus, textarea:focus, select:focus {
  outline: none;
  border-color: var(--color-accent);
}