:root {
  /* Light Theme */
  --bg-color: oklch(0.98 0.01 240);
  --text-color: oklch(0.2 0.01 240);
  --card-bg: oklch(1 0 0 / 0.8);
  --accent-color: oklch(0.6 0.2 250);
  --button-hover: oklch(0.5 0.2 250);
  --shadow: 0 10px 30px oklch(0 0 0 / 0.1);
  --ball-text: #fff;
  --nav-height: 70px;
}

[data-theme="dark"] {
  /* Dark Theme */
  --bg-color: oklch(0.15 0.02 240);
  --text-color: oklch(0.95 0.01 240);
  --card-bg: oklch(0.2 0.03 240 / 0.8);
  --accent-color: oklch(0.7 0.15 250);
  --button-hover: oklch(0.8 0.15 250);
  --shadow: 0 10px 30px oklch(0 0 0 / 0.3);
}

* {
  box-sizing: border-box;
  transition: background-color 0.3s ease, color 0.3s ease;
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  margin: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 100vh;
  background-color: var(--bg-color);
  color: var(--text-color);
  padding-top: var(--nav-height);
}

#app {
  width: 100%;
  max-width: 800px;
  display: flex;
  flex-direction: column;
  gap: 4rem;
  padding: 40px 20px;
}

/* Navbar */
.navbar {
  position: fixed;
  top: 0;
  width: 100%;
  height: var(--nav-height);
  background: var(--card-bg);
  backdrop-filter: blur(15px);
  border-bottom: 1px solid oklch(0.5 0 0 / 0.1);
  display: flex;
  justify-content: center;
  z-index: 900;
}

.nav-content {
  width: 100%;
  max-width: 800px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 20px;
}

.logo {
  font-weight: 900;
  font-size: 1.4rem;
  letter-spacing: -0.05em;
  color: var(--accent-color);
}

.nav-links {
  display: flex;
  gap: 1.5rem;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-color);
  font-weight: 600;
  font-size: 0.95rem;
  opacity: 0.7;
  transition: opacity 0.2s;
}

.nav-links a:hover {
  opacity: 1;
}

/* Hero Section */
.hero {
  text-align: center;
  padding: 2rem 0;
}

.hero h1 {
  font-size: clamp(2.5rem, 8vw, 3.5rem);
  font-weight: 900;
  letter-spacing: -0.06em;
  margin: 0;
  line-height: 1.1;
  background: linear-gradient(135deg, var(--accent-color), oklch(0.7 0.2 330));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero p {
  font-size: 1.2rem;
  opacity: 0.7;
  max-width: 600px;
  margin: 1.5rem auto 0;
  line-height: 1.6;
}

/* Content Sections */
.content-section {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.description-card {
  background: var(--card-bg);
  padding: 2rem;
  border-radius: 20px;
  border: 1px solid oklch(0.5 0 0 / 0.05);
  box-shadow: var(--shadow);
}

.description-card h3 {
  margin: 0 0 1rem 0;
  font-size: 1.3rem;
  font-weight: 700;
}

.description-card p {
  line-height: 1.7;
  opacity: 0.8;
  margin: 0 0 1rem 0;
}

.info-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
}

.info-cards .card {
  background: var(--card-bg);
  padding: 2rem;
  border-radius: 20px;
  box-shadow: var(--shadow);
  border: 1px solid oklch(0.5 0 0 / 0.05);
}

/* Footer */
.footer {
  width: 100%;
  background: var(--card-bg);
  padding: 4rem 20px;
  margin-top: 4rem;
  border-top: 1px solid oklch(0.5 0 0 / 0.1);
  display: flex;
  justify-content: center;
}

.footer-content {
  width: 100%;
  max-width: 800px;
  text-align: center;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-top: 1.5rem;
}

.footer-links a {
  text-decoration: none;
  color: var(--text-color);
  font-size: 0.9rem;
  opacity: 0.6;
}

.theme-toggle {
  position: fixed;
  bottom: 30px;
  right: 30px;
  background: var(--card-bg);
  border: 1px solid var(--accent-color);
  color: var(--text-color);
  padding: 10px;
  border-radius: 50%;
  cursor: pointer;
  box-shadow: var(--shadow);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 50px;
  height: 50px;
  font-size: 1.3rem;
  z-index: 1000;
}

@media (max-width: 600px) {
  .nav-links { display: none; }
  .hero h1 { font-size: 2.5rem; }
}