/* Design System */
:root {
  --color-primary: hsl(220, 90%, 50%);
  --color-secondary: hsl(280, 50%, 60%);
  --color-accent: hsl(40, 100%, 60%);
  --color-text: hsl(0, 0%, 20%);
  --color-bg: hsl(0, 0%, 98%);
  --color-card: hsl(0, 0%, 100%);
  --color-border: hsl(0, 0%, 90%);
  --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  --radius: 16px;
  --font-family: system-ui, -apple-system, sans-serif;
  --font-size-base: 16px;
  --spacing: 1rem;
}

[data-theme="dark"] {
  --color-text: hsl(0, 0%, 90%);
  --color-bg: hsl(0, 0%, 10%);
  --color-card: hsl(0, 0%, 15%);
  --color-border: hsl(0, 0%, 25%);
  --shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  transition: background-color 0.3s, color 0.3s;
}

header {
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  color: white;
  padding: 2rem;
  text-align: center;
  box-shadow: var(--shadow);
}

nav ul {
  list-style: none;
  display: flex;
  justify-content: center;
  background: var(--color-card);
  padding: 1rem;
  box-shadow: var(--shadow);
}

nav a {
  color: var(--color-text);
  text-decoration: none;
  padding: 0.5rem 1rem;
  border-radius: var(--radius);
  transition: background-color 0.3s;
}

nav a:hover, nav a:focus {
  background-color: var(--color-primary);
  color: white;
}

main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem;
}

section {
  margin-bottom: 3rem;
}

h1, h2 {
  margin-bottom: 1rem;
}

button {
  background: var(--color-primary);
  color: white;
  border: none;
  padding: 0.5rem 1rem;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: var(--font-size-base);
  transition: background-color 0.3s;
}

button:hover, button:focus {
  background: hsl(220, 90%, 40%);
  outline: 2px solid var(--color-accent);
}

#filters {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin-bottom: 2rem;
}

#dino-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1rem;
}

.card {
  background: var(--color-card);
  border-radius: var(--radius);
  padding: 1rem;
  box-shadow: var(--shadow);
  transition: transform 0.3s;
}

.card:hover {
  transform: translateY(-5px);
}

.chip {
  display: inline-block;
  background: var(--color-accent);
  color: var(--color-text);
  padding: 0.25rem 0.5rem;
  border-radius: 12px;
  font-size: 0.8rem;
  margin: 0.25rem;
}

#timeline-svg {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}

.modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 1000;
}

.modal-content {
  background: var(--color-card);
  padding: 2rem;
  border-radius: var(--radius);
  max-width: 80%;
  max-height: 80%;
  overflow-y: auto;
}

.tooltip {
  position: relative;
  display: inline-block;
}

.tooltip .tooltiptext {
  visibility: hidden;
  background: var(--color-text);
  color: var(--color-bg);
  padding: 0.5rem;
  border-radius: var(--radius);
  position: absolute;
  z-index: 1;
  bottom: 125%;
  left: 50%;
  transform: translateX(-50%);
  opacity: 0;
  transition: opacity 0.3s;
}

.tooltip:hover .tooltiptext {
  visibility: visible;
  opacity: 1;
}

footer {
  text-align: center;
  padding: 2rem;
  background: var(--color-card);
  box-shadow: var(--shadow);
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}