@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&display=swap');

:root {
  /* Light Theme Variables */
  --bg-main: #f4f6f9;
  --bg-secondary: #ffffff;
  --bg-glass: rgba(255, 255, 255, 0.65);
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --accent-color: #2563eb;
  --accent-gradient: linear-gradient(135deg, #2563eb, #3b82f6);
  --shadow-soft: 0 10px 25px -5px rgba(0, 0, 0, 0.05), 0 8px 10px -6px rgba(0, 0, 0, 0.01);
  --shadow-3d: 6px 6px 12px rgba(163, 177, 198, 0.4), -6px -6px 12px rgba(255, 255, 255, 0.9);
  --shadow-3d-inset: inset 4px 4px 8px rgba(163, 177, 198, 0.4), inset -4px -4px 8px rgba(255, 255, 255, 0.9);
  --border-color: rgba(226, 232, 240, 0.8);
  --glass-border: 1px solid rgba(255, 255, 255, 0.5);
  --nav-bg: rgba(244, 246, 249, 0.85);
  --danger: #ef4444;
  --success: #10b981;
}

[data-theme="dark"] {
  /* Dark Theme Variables - Navy / Dark Blue aesthetic */
  --bg-main: #0b1120;
  --bg-secondary: #1e293b;
  --bg-glass: rgba(30, 41, 59, 0.7);
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --accent-color: #3b82f6;
  --accent-gradient: linear-gradient(135deg, #3b82f6, #60a5fa);
  --shadow-soft: 0 10px 25px -5px rgba(0, 0, 0, 0.5), 0 8px 10px -6px rgba(0, 0, 0, 0.3);
  --shadow-3d: 6px 6px 15px rgba(0, 0, 0, 0.6), -6px -6px 15px rgba(30, 41, 59, 0.5);
  --shadow-3d-inset: inset 4px 4px 8px rgba(0, 0, 0, 0.6), inset -4px -4px 8px rgba(30, 41, 59, 0.5);
  --border-color: rgba(51, 65, 85, 0.8);
  --glass-border: 1px solid rgba(255, 255, 255, 0.05);
  --nav-bg: rgba(11, 17, 32, 0.85);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Inter', sans-serif;
}

body {
  background-color: var(--bg-main);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  transition: background-color 0.3s ease, color 0.3s ease;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1;
  padding-top: 80px; /* offset for sticky header */
  padding-bottom: 80px; /* prevent touching footer */
}

a {
  text-decoration: none;
  color: var(--accent-color);
  transition: color 0.2s ease;
}

a:hover {
  filter: brightness(1.2);
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Typography SEO */
h1, h2, h3, h4, h5, h6 {
  color: var(--text-primary);
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: 1rem;
}

h1 { font-size: 2.8rem; letter-spacing: -0.02em; }
h2 { font-size: 2.2rem; }
h3 { font-size: 1.5rem; }

p {
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

ul {
  padding-left: 1.5rem;
  margin-bottom: 1rem;
  color: var(--text-secondary);
}

li {
  margin-bottom: 0.5rem;
}

.text-gradient {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.text-center { text-align: center; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mb-5 { margin-bottom: 3rem; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mt-5 { margin-top: 3rem; }

section {
  padding: 80px 0;
}

@media (max-width: 1024px) {
  main {
    padding-bottom: 70px;
  }
}

@media (max-width: 768px) {
  h1 { font-size: 2rem; }
  h2 { font-size: 1.7rem; }
  section { padding: 50px 0; }
  
  main {
    padding-bottom: 60px;
  }
}