/**
 * Ömer Faruk ÖZKAN - Portfolio Website
 * Dark Theme / Developer-Friendly Design
 * GitHub Dark Color Palette
 */

/* ===== CSS Variables ===== */
:root {
  /* GitHub Dark Palette */
  --bg-primary: #0d1117;
  --bg-secondary: #161b22;
  --bg-tertiary: #21262d;
  --border-color: #30363d;
  --border-muted: #21262d;

  /* Text Colors */
  --text-primary: #c9d1d9;
  --text-secondary: #8b949e;
  --text-muted: #6e7681;

  /* Accent Colors */
  --primary: #58a6ff;
  --primary-hover: #79b8ff;
  --success: #238636;
  --success-hover: #2ea043;
  --warning: #d29922;
  --error: #f85149;
  --accent: #39d353;

  /* Code/Syntax Colors */
  --code-keyword: #ff7b72;
  --code-string: #a5d6ff;
  --code-function: #d2a8ff;
  --code-comment: #8b949e;
  --code-number: #79c0ff;

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

  /* Typography */
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Source Code Pro', monospace;
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans', Helvetica, Arial, sans-serif;

  /* Borders */
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;

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

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-mono);
  font-weight: 600;
  line-height: 1.25;
  margin-bottom: var(--spacing-md);
}

h1 { font-size: clamp(1.75rem, 5vw, 2.5rem); }
h2 { font-size: clamp(1.5rem, 4vw, 2rem); }
h3 { font-size: clamp(1.25rem, 3vw, 1.5rem); }
h4 { font-size: 1.125rem; }

p {
  margin-bottom: var(--spacing-md);
  color: var(--text-secondary);
}

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

a:hover {
  color: var(--primary-hover);
}

/* ===== Layout ===== */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

main {
  flex: 1;
  padding: var(--spacing-xl) 0;
}

/* ===== Header ===== */
.header {
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(10px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-md) 0;
}

.logo {
  font-family: var(--font-mono);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.logo::before {
  content: '>_';
  color: var(--accent);
}

.logo:hover {
  color: var(--primary);
}

/* Navigation */
.nav {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.nav-link {
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-md);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--text-secondary);
  transition: all var(--transition-fast);
  position: relative;
}

.nav-link:hover {
  color: var(--text-primary);
  background-color: var(--bg-tertiary);
}

.nav-link.active {
  color: var(--primary);
}

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 50%;
  transform: translateX(-50%);
  width: 20px;
  height: 2px;
  background-color: var(--primary);
  border-radius: 2px;
}

/* Language Switcher */
.lang-switcher {
  display: flex;
  gap: var(--spacing-xs);
  padding: var(--spacing-xs);
  background-color: var(--bg-tertiary);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.lang-btn {
  padding: var(--spacing-xs) var(--spacing-sm);
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.lang-btn:hover {
  color: var(--text-primary);
}

.lang-btn.active {
  background-color: var(--primary);
  color: var(--bg-primary);
}

/* ===== Hero Section ===== */
.hero {
  text-align: center;
  padding: var(--spacing-2xl) 0;
}

.hero-title {
  font-family: var(--font-mono);
  font-size: 1.125rem;
  color: var(--accent);
  margin-bottom: var(--spacing-sm);
}

.hero-name {
  font-size: clamp(2.5rem, 8vw, 4rem);
  font-weight: 700;
  margin-bottom: var(--spacing-sm);
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--primary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-family: var(--font-mono);
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xl);
}

.hero-bio {
  max-width: 600px;
  margin: 0 auto var(--spacing-xl);
  font-size: 1.125rem;
  line-height: 1.8;
}

/* ===== Stats ===== */
.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-md);
  margin: var(--spacing-xl) 0;
}

.stat-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  text-align: center;
  transition: all var(--transition-normal);
}

.stat-card:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
}

.stat-value {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  color: var(--primary);
}

.stat-label {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-top: var(--spacing-xs);
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-lg);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
}

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

.btn-primary {
  background-color: var(--success);
  border-color: var(--success);
  color: white;
}

.btn-primary:hover {
  background-color: var(--success-hover);
  border-color: var(--success-hover);
}

.btn-icon {
  width: 40px;
  height: 40px;
  padding: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
}

/* ===== Cards ===== */
.card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  margin-bottom: var(--spacing-md);
  transition: all var(--transition-normal);
}

.card:hover {
  border-color: var(--primary);
  box-shadow: 0 4px 20px rgba(88, 166, 255, 0.1);
}

.card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: var(--spacing-md);
}

.card-title {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--spacing-xs);
}

.card-subtitle {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--primary);
}

.card-meta {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.card-content {
  color: var(--text-secondary);
}

.card-badge {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-sm);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  background-color: var(--bg-tertiary);
  color: var(--accent);
  border-radius: var(--radius-sm);
}

/* ===== Skills ===== */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}

.skill-category {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
}

.skill-category-title {
  font-family: var(--font-mono);
  font-size: 1rem;
  color: var(--text-primary);
  margin-bottom: var(--spacing-md);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.skill-category-title::before {
  content: '$';
  color: var(--accent);
}

.skill-list {
  list-style: none;
}

.skill-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-sm) 0;
  border-bottom: 1px solid var(--border-muted);
}

.skill-item:last-child {
  border-bottom: none;
}

.skill-name {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.skill-bar {
  width: 100px;
  height: 6px;
  background-color: var(--bg-tertiary);
  border-radius: 3px;
  overflow: hidden;
}

.skill-progress {
  height: 100%;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  border-radius: 3px;
  transition: width var(--transition-slow);
}

/* ===== Certifications ===== */
.certifications {
  margin-top: var(--spacing-xl);
}

.certifications-title {
  font-family: var(--font-mono);
  font-size: 1.25rem;
  margin-bottom: var(--spacing-md);
}

.cert-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: var(--spacing-sm);
}

.cert-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm);
  background-color: var(--bg-tertiary);
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.cert-item::before {
  content: '✓';
  color: var(--accent);
  font-weight: 700;
}

/* ===== Contact Form ===== */
.contact-section {
  max-width: 600px;
  margin: 0 auto;
}

.contact-subtitle {
  text-align: center;
  margin-bottom: var(--spacing-xl);
  color: var(--text-secondary);
}

.form {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}

.form-label {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.form-label::before {
  content: '>';
  color: var(--primary);
}

.form-input,
.form-textarea {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  transition: all var(--transition-fast);
}

.form-input:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.1);
}

.form-textarea {
  min-height: 150px;
  resize: vertical;
}

.form-input.error,
.form-textarea.error {
  border-color: var(--error);
}

.form-error {
  font-size: 0.75rem;
  color: var(--error);
  margin-top: var(--spacing-xs);
}

.form-submit {
  padding: var(--spacing-sm) var(--spacing-xl);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 600;
  background-color: var(--success);
  border: 1px solid var(--success);
  border-radius: var(--radius-md);
  color: white;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.form-submit:hover {
  background-color: var(--success-hover);
}

.form-submit:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

/* ===== Alerts ===== */
.alert {
  padding: var(--spacing-md);
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-md);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: 0.875rem;
}

.alert-success {
  background-color: rgba(35, 134, 54, 0.1);
  border: 1px solid var(--success);
  color: var(--success);
}

.alert-error {
  background-color: rgba(248, 81, 73, 0.1);
  border: 1px solid var(--error);
  color: var(--error);
}

.alert-success::before {
  content: '✓';
  font-weight: 700;
}

.alert-error::before {
  content: '!';
  font-weight: 700;
}

/* ===== Footer ===== */
.footer {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: var(--spacing-lg) 0;
  margin-top: auto;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-md);
  text-align: center;
}

.footer-links {
  display: flex;
  gap: var(--spacing-md);
}

.footer-link {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  transition: all var(--transition-fast);
}

.footer-link:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.footer-text {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* ===== Code Block ===== */
.code-block {
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.6;
}

.code-block::before {
  content: '>';
  color: var(--accent);
  margin-right: var(--spacing-sm);
}

/* ===== Animations ===== */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation: fadeIn var(--transition-slow) ease-out;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .header-inner {
    flex-wrap: wrap;
    gap: var(--spacing-sm);
  }

  .nav {
    order: 3;
    width: 100%;
    justify-content: center;
    flex-wrap: wrap;
  }

  .hero-name {
    font-size: 2rem;
  }

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

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

  .card-header {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
}

@media (max-width: 480px) {
  .lang-switcher {
    order: -1;
    margin-left: auto;
  }

  .hero {
    padding: var(--spacing-lg) 0;
  }

  .form-input,
  .form-textarea {
    font-size: 16px; /* Prevent zoom on iOS */
  }
}

/* ===== Utility Classes ===== */
.text-center { text-align: center; }
.text-muted { color: var(--text-muted); }
.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }