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

:root {
  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;

  /* Typography */
  --font-xs: 0.75rem;
  --font-sm: 0.875rem;
  --font-base: 1rem;
  --font-lg: 1.125rem;
  --font-xl: 1.5rem;
  --font-2xl: 2rem;
  --font-3xl: 2.5rem;

  /* Borders */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.12);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.15);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.2);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 350ms ease;
}

/* =================================
   Theme Colors
   ================================= */
[data-theme="auto"] {
  color-scheme: light dark;
}

[data-theme="light"] {
  --bg-primary: #ffffff;
  --bg-secondary: #f5f5f5;
  --bg-tertiary: #e8e8e8;
  --text-primary: #1a1a1a;
  --text-secondary: #666666;
  --text-tertiary: #999999;
  --accent-primary: #2962ff;
  --accent-secondary: #448aff;
  --border-color: #e0e0e0;
  --card-bg: #ffffff;
}

[data-theme="dark"] {
  --bg-primary: #0d1117;
  --bg-secondary: #161b22;
  --bg-tertiary: #21262d;
  --text-primary: #f0f6fc;
  --text-secondary: #8b949e;
  --text-tertiary: #6e7681;
  --accent-primary: #58a6ff;
  --accent-secondary: #1f6feb;
  --border-color: #30363d;
  --card-bg: #161b22;
}

[data-theme="retro"] {
  --bg-primary: #2d2a32;
  --bg-secondary: #3c3a45;
  --bg-tertiary: #4a4753;
  --text-primary: #ffeb99;
  --text-secondary: #ffb48a;
  --text-tertiary: #d9a36c;
  --accent-primary: #ff6f61;
  --accent-secondary: #ff8975;
  --border-color: #5a5662;
  --card-bg: #3c3a45;
}

[data-theme="cosmic"] {
  --bg-primary: #0b0c10;
  --bg-secondary: #1f2833;
  --bg-tertiary: #2c3440;
  --text-primary: #c5c6c7;
  --text-secondary: #66fcf1;
  --text-tertiary: #45a29e;
  --accent-primary: #66fcf1;
  --accent-secondary: #45a29e;
  --border-color: #3a4552;
  --card-bg: #1f2833;
}

[data-theme="sunset"] {
  --bg-primary: #1e1e2e;
  --bg-secondary: #3c2a3e;
  --bg-tertiary: #4f3a4f;
  --text-primary: #ffd580;
  --text-secondary: #ff9f68;
  --text-tertiary: #e88765;
  --accent-primary: #ff6b6b;
  --accent-secondary: #ff8787;
  --border-color: #5f4a5f;
  --card-bg: #3c2a3e;
}

[data-theme="earth"] {
  --bg-primary: #2e2d2b;
  --bg-secondary: #3b3a36;
  --bg-tertiary: #4a4945;
  --text-primary: #d9cbbf;
  --text-secondary: #a3b18a;
  --text-tertiary: #8a9a77;
  --accent-primary: #588157;
  --accent-secondary: #6b9a69;
  --border-color: #5a5955;
  --card-bg: #3b3a36;
}

[data-theme="ocean"] {
  --bg-primary: #001f3f;
  --bg-secondary: #003566;
  --bg-tertiary: #004d7a;
  --text-primary: #e0f7fa;
  --text-secondary: #90caf9;
  --text-tertiary: #64b5f6;
  --accent-primary: #00bcd4;
  --accent-secondary: #26c6da;
  --border-color: #004d7a;
  --card-bg: #003566;
}

[data-theme="solarized"] {
  --bg-primary: #002b36;
  --bg-secondary: #073642;
  --bg-tertiary: #0e4b59;
  --text-primary: #839496;
  --text-secondary: #93a1a1;
  --text-tertiary: #657b83;
  --accent-primary: #b58900;
  --accent-secondary: #cb4b16;
  --border-color: #0e4b59;
  --card-bg: #073642;
}

/* Auto theme detection */
@media (prefers-color-scheme: dark) {
  [data-theme="auto"] {
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-tertiary: #21262d;
    --text-primary: #f0f6fc;
    --text-secondary: #8b949e;
    --text-tertiary: #6e7681;
    --accent-primary: #58a6ff;
    --accent-secondary: #1f6feb;
    --border-color: #30363d;
    --card-bg: #161b22;
  }
}

@media (prefers-color-scheme: light) {
  [data-theme="auto"] {
    --bg-primary: #ffffff;
    --bg-secondary: #f5f5f5;
    --bg-tertiary: #e8e8e8;
    --text-primary: #1a1a1a;
    --text-secondary: #666666;
    --text-tertiary: #999999;
    --accent-primary: #2962ff;
    --accent-secondary: #448aff;
    --border-color: #e0e0e0;
    --card-bg: #ffffff;
  }
}

/* =================================
   Base Styles
   ================================= */
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  transition: background-color var(--transition-base),
    color var(--transition-base);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Accessibility */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

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

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

/* =================================
   Header
   ================================= */
.site-header {
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  padding: var(--space-lg) 0;
  position: sticky;
  top: 0;
  z-index: 1000;
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-sm);
}

.header-content {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  margin-bottom: var(--space-md);
}

.avatar {
  width: 80px;
  height: 80px;
  border-radius: var(--radius-full);
  border: 3px solid var(--accent-primary);
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-base);
}

.avatar:hover {
  transform: scale(1.05) rotate(5deg);
}

.header-text h1 {
  font-size: var(--font-3xl);
  font-weight: 700;
  background: linear-gradient(
    135deg,
    var(--accent-primary),
    var(--accent-secondary)
  );
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--space-xs);
}

.tagline {
  color: var(--text-secondary);
  font-size: var(--font-lg);
}

.controls {
  display: flex;
  justify-content: flex-end;
  gap: var(--space-sm);
}

.controls select {
  padding: var(--space-sm) var(--space-md);
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  font-size: var(--font-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.controls select:hover,
.controls select:focus {
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.1);
  outline: none;
}

/* =================================
   Navigation
   ================================= */
.main-nav {
  background: var(--bg-secondary);
  padding: var(--space-lg) 0;
  border-bottom: 1px solid var(--border-color);
}

.nav-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-md);
}

.nav-card {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  text-decoration: none;
  color: var(--text-primary);
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.nav-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(
    90deg,
    var(--accent-primary),
    var(--accent-secondary)
  );
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-base);
}

.nav-card:hover,
.nav-card:focus {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--accent-primary);
}

.nav-card:hover::before {
  transform: scaleX(1);
}

.nav-card-icon {
  font-size: var(--font-3xl);
  margin-bottom: var(--space-sm);
  display: block;
}

.nav-card h3 {
  font-size: var(--font-xl);
  margin-bottom: var(--space-xs);
  color: var(--accent-primary);
}

.nav-card p {
  color: var(--text-secondary);
  font-size: var(--font-sm);
  line-height: 1.5;
}

.nav-card-badge {
  display: inline-block;
  margin-top: var(--space-sm);
  padding: var(--space-xs) var(--space-sm);
  background: var(--accent-primary);
  color: white;
  font-size: var(--font-xs);
  font-weight: 600;
  border-radius: var(--radius-full);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* =================================
   Main Content
   ================================= */
.main-content {
  flex: 1;
  padding: var(--space-2xl) 0;
}

.welcome-section {
  text-align: center;
  margin-bottom: var(--space-2xl);
  padding: var(--space-xl);
  background: var(--card-bg);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
}

.welcome-section h2 {
  font-size: var(--font-2xl);
  margin-bottom: var(--space-md);
  color: var(--accent-primary);
}

.welcome-section p {
  font-size: var(--font-lg);
  color: var(--text-secondary);
  max-width: 700px;
  margin: 0 auto;
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--space-lg);
}

.project-card {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.project-card::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(
    90deg,
    var(--accent-primary),
    var(--accent-secondary)
  );
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-base);
}

.project-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
  border-color: var(--accent-primary);
}

.project-card:hover::after {
  transform: scaleX(1);
}

.project-card h3 {
  font-size: var(--font-xl);
  margin-bottom: var(--space-sm);
  color: var(--text-primary);
}

.project-card p {
  color: var(--text-secondary);
  margin-bottom: var(--space-md);
  line-height: 1.6;
}

.project-links {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.btn {
  padding: var(--space-sm) var(--space-md);
  background: var(--accent-primary);
  color: white;
  text-decoration: none;
  border-radius: var(--radius-md);
  font-size: var(--font-sm);
  font-weight: 600;
  transition: all var(--transition-fast);
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
}

.btn:hover {
  background: var(--accent-secondary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-secondary {
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background: var(--bg-secondary);
  border-color: var(--accent-primary);
}

/* =================================
   Footer
   ================================= */
.site-footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: var(--space-xl) 0;
  text-align: center;
  color: var(--text-secondary);
  font-size: var(--font-sm);
}

.footer-content {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  align-items: center;
}

.footer-content a {
  color: var(--accent-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer-content a:hover {
  color: var(--accent-secondary);
  text-decoration: underline;
}

.visit-counter {
  padding: var(--space-sm) var(--space-lg);
  background: var(--accent-primary);
  color: white;
  border-radius: var(--radius-full);
  font-weight: 600;
  box-shadow: var(--shadow-md);
}

/* =================================
   Responsive Design
   ================================= */
@media (max-width: 768px) {
  .header-content {
    flex-direction: column;
    text-align: center;
  }

  .header-text h1 {
    font-size: var(--font-2xl);
  }

  .tagline {
    font-size: var(--font-base);
  }

  .nav-grid {
    grid-template-columns: 1fr;
  }

  .projects-grid {
    grid-template-columns: 1fr;
  }

  .controls {
    justify-content: center;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 var(--space-md);
  }

  .avatar {
    width: 60px;
    height: 60px;
  }
}

/* =================================
   Loading State
   ================================= */
.loading {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 300px;
}

.spinner {
  width: 50px;
  height: 50px;
  border: 4px solid var(--border-color);
  border-top-color: var(--accent-primary);
  border-radius: var(--radius-full);
  animation: spin 1s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}