/* ==========================================================================
   Base & CSS Variables (Theme Configuration)
   ========================================================================== */
:root {
  /* Light Theme (Default) */
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-tertiary: #f1f5f9;
  --bg-card: rgba(255, 255, 255, 0.85);
  --bg-card-border: rgba(226, 232, 240, 0.8);
  
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --text-light: #94a3b8;

  --accent-primary: #3b82f6;
  --accent-secondary: #6366f1;
  --accent-gradient: linear-gradient(135deg, #3b82f6 0%, #6366f1 50%, #8b5cf6 100%);
  --accent-gradient-hover: linear-gradient(135deg, #2563eb 0%, #4f46e5 50%, #7c3aed 100%);
  --accent-light: rgba(59, 130, 246, 0.1);
  --accent-border: rgba(59, 130, 246, 0.2);

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.05);
  --shadow-glow: 0 0 25px rgba(59, 130, 246, 0.25);

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-full: 9999px;

  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);

  --nav-height: 72px;
  --font-main: 'Pretendard', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-code: 'Fira Code', monospace;
}

[data-theme="dark"] {
  --bg-primary: #0a0f1d;
  --bg-secondary: #0f172a;
  --bg-tertiary: #1e293b;
  --bg-card: rgba(15, 23, 42, 0.75);
  --bg-card-border: rgba(51, 65, 85, 0.6);

  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --text-light: #64748b;

  --accent-primary: #60a5fa;
  --accent-secondary: #818cf8;
  --accent-gradient: linear-gradient(135deg, #60a5fa 0%, #818cf8 50%, #a78bfa 100%);
  --accent-gradient-hover: linear-gradient(135deg, #3b82f6 0%, #6366f1 50%, #8b5cf6 100%);
  --accent-light: rgba(96, 165, 250, 0.15);
  --accent-border: rgba(96, 165, 250, 0.3);

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -2px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -4px rgba(0, 0, 0, 0.3);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.6), 0 8px 10px -6px rgba(0, 0, 0, 0.4);
  --shadow-glow: 0 0 30px rgba(96, 165, 250, 0.35);
}

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

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

body {
  font-family: var(--font-main);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.65;
  transition: background-color var(--transition-normal), color var(--transition-normal);
  overflow-x: hidden;
  position: relative;
}

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

ul {
  list-style: none;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

button, input, textarea {
  font-family: inherit;
  font-size: inherit;
  border: none;
  outline: none;
}

button {
  cursor: pointer;
  background: none;
}

/* Container */
.container {
  width: 100%;
  max-width: 1160px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Section Shared Styles */
.section {
  padding: 100px 0;
  position: relative;
}

.section-header {
  text-align: center;
  margin-bottom: 56px;
}

.section-subtitle {
  display: inline-block;
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--accent-primary);
  margin-bottom: 8px;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 16px;
  letter-spacing: -0.5px;
}

.title-bar {
  width: 48px;
  height: 4px;
  background: var(--accent-gradient);
  border-radius: var(--radius-full);
  margin: 0 auto;
}

/* Common Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 12px 26px;
  font-weight: 600;
  font-size: 0.95rem;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.btn-primary {
  background: var(--accent-gradient);
  color: #ffffff !important;
  box-shadow: 0 4px 15px rgba(59, 130, 246, 0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(59, 130, 246, 0.45);
}

.btn-outline {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--bg-card-border);
  backdrop-filter: blur(8px);
}

.btn-outline:hover {
  border-color: var(--accent-primary);
  color: var(--accent-primary);
  transform: translateY(-2px);
}

.btn-block {
  width: 100%;
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--nav-height);
  z-index: 1000;
  background: rgba(var(--bg-primary), 0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: all var(--transition-normal);
}

.header.scrolled {
  background: var(--bg-card);
  border-bottom: 1px solid var(--bg-card-border);
  box-shadow: var(--shadow-sm);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.logo {
  font-family: var(--font-code);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  letter-spacing: -0.5px;
}

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

.logo-name {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin: 0 2px;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-link {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
  position: relative;
  padding: 4px 0;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0%;
  height: 2px;
  background: var(--accent-gradient);
  transition: width var(--transition-fast);
  border-radius: var(--radius-full);
}

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

.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.theme-toggle-btn {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  background: var(--bg-tertiary);
  border: 1px solid var(--bg-card-border);
  transition: all var(--transition-fast);
}

.theme-toggle-btn:hover {
  color: var(--accent-primary);
  transform: rotate(15deg);
}

[data-theme="light"] .dark-icon {
  display: block;
}
[data-theme="light"] .light-icon {
  display: none;
}
[data-theme="dark"] .dark-icon {
  display: none;
}
[data-theme="dark"] .light-icon {
  display: block;
  color: #fbbf24;
}

.mobile-menu-btn {
  display: none;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  align-items: center;
  justify-content: center;
  color: var(--text-primary);
  font-size: 1.25rem;
  background: var(--bg-tertiary);
}

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero-section {
  min-height: 100vh;
  padding-top: calc(var(--nav-height) + 40px);
  padding-bottom: 60px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  position: relative;
  overflow: hidden;
  background: radial-gradient(circle at 10% 20%, var(--accent-light) 0%, transparent 40%),
              radial-gradient(circle at 90% 80%, rgba(139, 92, 246, 0.08) 0%, transparent 40%);
}

.hero-container {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  align-items: center;
  gap: 48px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  background: var(--accent-light);
  border: 1px solid var(--accent-border);
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent-primary);
  margin-bottom: 24px;
}

.pulse-dot {
  width: 8px;
  height: 8px;
  background: #10b981;
  border-radius: 50%;
  box-shadow: 0 0 0 rgba(16, 185, 129, 0.6);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% {
    box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.6);
  }
  70% {
    box-shadow: 0 0 0 8px rgba(16, 185, 129, 0);
  }
  100% {
    box-shadow: 0 0 0 0 rgba(16, 185, 129, 0);
  }
}

.hero-title {
  font-size: 3.25rem;
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -1px;
  margin-bottom: 16px;
}

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

.typing-wrapper {
  font-size: 1.4rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 20px;
  min-height: 36px;
  display: flex;
  align-items: center;
}

.typing-text {
  color: var(--accent-primary);
  margin-left: 4px;
}

.cursor {
  display: inline-block;
  width: 2px;
  background-color: var(--accent-primary);
  animation: blink 1s infinite;
  margin-left: 2px;
}

@keyframes blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

.hero-description {
  font-size: 1.1rem;
  color: var(--text-secondary);
  max-width: 540px;
  margin-bottom: 32px;
}

.hero-cta-group {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 36px;
}

.social-links {
  display: flex;
  gap: 14px;
}

.social-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background: var(--bg-secondary);
  border: 1px solid var(--bg-card-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  color: var(--text-secondary);
  transition: all var(--transition-fast);
}

.social-icon:hover {
  color: #ffffff;
  background: var(--accent-gradient);
  border-color: transparent;
  transform: translateY(-3px);
  box-shadow: 0 6px 15px rgba(59, 130, 246, 0.3);
}

/* Hero Visual & Profile Card */
.profile-card-wrapper {
  position: relative;
  display: flex;
  justify-content: center;
}

.profile-blob {
  position: absolute;
  width: 320px;
  height: 320px;
  background: var(--accent-gradient);
  filter: blur(60px);
  opacity: 0.25;
  border-radius: 50%;
  z-index: 1;
}

.profile-card {
  position: relative;
  z-index: 2;
  background: var(--bg-card);
  border: 1px solid var(--bg-card-border);
  backdrop-filter: blur(16px);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-xl);
  max-width: 360px;
  width: 100%;
}

.profile-img-container {
  width: 120px;
  height: 120px;
  margin: 0 auto 20px;
  border-radius: 50%;
  padding: 4px;
  background: var(--accent-gradient);
  box-shadow: var(--shadow-glow);
}

.profile-avatar-fallback {
  width: 100%;
  height: 100%;
  background: var(--bg-tertiary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3rem;
  color: var(--accent-primary);
}

.profile-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 50%;
}

.code-snippet-box {
  background: #0f172a;
  border-radius: var(--radius-sm);
  padding: 14px;
  color: #f8fafc;
  font-family: var(--font-code);
  font-size: 0.82rem;
  box-shadow: inset 0 2px 4px rgba(0,0,0,0.4);
}

.code-dots {
  display: flex;
  gap: 6px;
  margin-bottom: 10px;
}

.code-dots .dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}
.dot.red { background-color: #ef4444; }
.dot.yellow { background-color: #f59e0b; }
.dot.green { background-color: #10b981; }

.code-content {
  overflow-x: auto;
  line-height: 1.5;
}

.code-content .keyword { color: #f43f5e; }
.code-content .variable { color: #38bdf8; }
.code-content .prop { color: #a78bfa; }
.code-content .string { color: #4ade80; }
.code-content .number { color: #fbbf24; }

/* Scroll Down Hint */
.scroll-down-hint {
  position: absolute;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.scroll-down-hint a {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
}

.mouse-icon {
  width: 22px;
  height: 34px;
  border: 2px solid var(--text-muted);
  border-radius: 12px;
  position: relative;
}

.mouse-icon .wheel {
  width: 4px;
  height: 6px;
  background-color: var(--accent-primary);
  border-radius: 2px;
  position: absolute;
  top: 6px;
  left: 50%;
  transform: translateX(-50%);
  animation: scrollWheel 1.5s infinite;
}

@keyframes scrollWheel {
  0% { top: 6px; opacity: 1; }
  100% { top: 18px; opacity: 0; }
}

/* ==========================================================================
   About Me Section
   ========================================================================== */
.about-section {
  background-color: var(--bg-secondary);
}

.about-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 48px;
  align-items: center;
}

.about-heading {
  font-size: 1.45rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 20px;
  color: var(--text-primary);
}

.about-paragraph {
  font-size: 1.05rem;
  color: var(--text-secondary);
  margin-bottom: 16px;
  line-height: 1.7;
}

.stat-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 32px;
}

.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--bg-card-border);
  padding: 20px 16px;
  border-radius: var(--radius-md);
  text-align: center;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-fast);
}

.stat-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.stat-number {
  font-size: 2rem;
  font-weight: 800;
  color: var(--accent-primary);
}

.stat-suffix {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent-secondary);
}

.stat-label {
  display: block;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 4px;
  font-weight: 500;
}

.about-cards-column {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--bg-card-border);
  padding: 22px;
  border-radius: var(--radius-md);
  display: flex;
  gap: 18px;
  align-items: flex-start;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-fast);
}

.feature-card:hover {
  transform: translateX(6px);
  border-color: var(--accent-border);
  box-shadow: var(--shadow-md);
}

.feature-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: var(--accent-light);
  color: var(--accent-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.35rem;
  flex-shrink: 0;
}

.feature-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 6px;
  color: var(--text-primary);
}

.feature-desc {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.55;
}

/* ==========================================================================
   Skills Section
   ========================================================================== */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.skill-category-card {
  background: var(--bg-card);
  border: 1px solid var(--bg-card-border);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-fast);
}

.skill-category-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-xl);
  border-color: var(--accent-border);
}

.category-header {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 24px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--bg-card-border);
}

.category-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
}

.category-icon.front { background: rgba(59, 130, 246, 0.15); color: #3b82f6; }
.category-icon.back { background: rgba(16, 185, 129, 0.15); color: #10b981; }
.category-icon.tools { background: rgba(245, 158, 11, 0.15); color: #f59e0b; }

.category-title {
  font-size: 1.2rem;
  font-weight: 700;
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.skill-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--bg-tertiary);
  border: 1px solid var(--bg-card-border);
  color: var(--text-primary);
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.88rem;
  font-weight: 500;
  transition: all var(--transition-fast);
}

.skill-tag:hover {
  background: var(--accent-light);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
  transform: translateY(-2px);
}

.skill-tag i {
  font-size: 1rem;
}

/* ==========================================================================
   Projects Section
   ========================================================================== */
.projects-section {
  background-color: var(--bg-secondary);
}

.project-filters {
  display: flex;
  justify-content: center;
  gap: 12px;
  margin-bottom: 40px;
  flex-wrap: wrap;
}

.filter-btn {
  padding: 8px 20px;
  border-radius: var(--radius-full);
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text-secondary);
  background: var(--bg-card);
  border: 1px solid var(--bg-card-border);
  transition: all var(--transition-fast);
}

.filter-btn:hover,
.filter-btn.active {
  background: var(--accent-gradient);
  color: #ffffff;
  border-color: transparent;
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 32px;
}

.project-card {
  background: var(--bg-card);
  border: 1px solid var(--bg-card-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
  display: flex;
  flex-direction: column;
}

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

.project-card.hide {
  display: none;
}

.project-thumb {
  position: relative;
  height: 200px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.gradient-1 { background: linear-gradient(135deg, #1e3a8a, #3b82f6); }
.gradient-2 { background: linear-gradient(135deg, #4c1d95, #8b5cf6); }
.gradient-3 { background: linear-gradient(135deg, #065f46, #10b981); }

.thumb-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  color: #ffffff;
  font-weight: 600;
  font-size: 1.05rem;
}

.thumb-icon {
  font-size: 2.8rem;
  opacity: 0.9;
}

.thumb-badge {
  position: absolute;
  top: 14px;
  left: 14px;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(6px);
  color: #ffffff;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.5px;
}

.project-overlay {
  position: absolute;
  inset: 0;
  background: rgba(15, 23, 42, 0.7);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.project-card:hover .project-overlay {
  opacity: 1;
}

.preview-btn {
  width: 44px;
  height: 44px;
  background: #ffffff;
  color: #0f172a;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  transition: all var(--transition-fast);
}

.preview-btn:hover {
  transform: scale(1.15);
  background: var(--accent-primary);
  color: #ffffff;
}

.project-info {
  padding: 24px;
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.project-techs {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 12px;
}

.project-techs span {
  font-size: 0.75rem;
  font-weight: 600;
  background: var(--accent-light);
  color: var(--accent-primary);
  padding: 3px 8px;
  border-radius: 4px;
}

.project-name {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text-primary);
}

.project-summary {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.55;
  margin-bottom: 16px;
}

.project-points {
  margin-bottom: 20px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.project-points li {
  font-size: 0.85rem;
  color: var(--text-muted);
  display: flex;
  align-items: flex-start;
  gap: 8px;
  line-height: 1.4;
}

.project-points li i {
  color: #10b981;
  margin-top: 3px;
  font-size: 0.8rem;
}

.project-links {
  margin-top: auto;
  display: flex;
  align-items: center;
  gap: 16px;
  padding-top: 14px;
  border-top: 1px solid var(--bg-card-border);
}

.btn-link {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-secondary);
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.btn-link:hover {
  color: var(--accent-primary);
}

/* ==========================================================================
   Experience & Timeline Section
   ========================================================================== */
.timeline-container {
  max-width: 800px;
  margin: 0 auto;
  position: relative;
  padding-left: 32px;
}

.timeline-container::before {
  content: '';
  position: absolute;
  top: 0;
  left: 7px;
  width: 2px;
  height: 100%;
  background: var(--bg-card-border);
}

.timeline-item {
  position: relative;
  margin-bottom: 40px;
}

.timeline-item:last-child {
  margin-bottom: 0;
}

.timeline-dot {
  position: absolute;
  top: 4px;
  left: -32px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--accent-primary);
  border: 3px solid var(--bg-primary);
  box-shadow: 0 0 0 3px var(--accent-light);
}

.timeline-date {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--accent-primary);
  margin-bottom: 6px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.timeline-content {
  background: var(--bg-card);
  border: 1px solid var(--bg-card-border);
  border-radius: var(--radius-md);
  padding: 22px 24px;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-fast);
}

.timeline-content:hover {
  transform: translateX(6px);
  border-color: var(--accent-border);
  box-shadow: var(--shadow-md);
}

.timeline-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.timeline-role {
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 12px;
}

.timeline-details {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.timeline-details li {
  font-size: 0.88rem;
  color: var(--text-muted);
  position: relative;
  padding-left: 14px;
  line-height: 1.5;
}

.timeline-details li::before {
  content: '•';
  position: absolute;
  left: 0;
  color: var(--accent-primary);
  font-weight: bold;
}

/* ==========================================================================
   Contact Section
   ========================================================================== */
.contact-section {
  background-color: var(--bg-secondary);
}

.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 48px;
}

.contact-info-title {
  font-size: 1.45rem;
  font-weight: 700;
  margin-bottom: 14px;
}

.contact-info-desc {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-bottom: 28px;
  line-height: 1.65;
}

.contact-card-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.contact-card {
  display: flex;
  align-items: center;
  gap: 16px;
  background: var(--bg-card);
  border: 1px solid var(--bg-card-border);
  padding: 16px 20px;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.contact-card:hover {
  transform: translateX(4px);
  border-color: var(--accent-border);
  box-shadow: var(--shadow-sm);
}

.contact-card-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background: var(--accent-light);
  color: var(--accent-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  flex-shrink: 0;
}

.contact-card-text {
  display: flex;
  flex-direction: column;
}

.contact-card-text .label {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-weight: 500;
}

.contact-card-text .value {
  font-size: 0.98rem;
  font-weight: 600;
  color: var(--text-primary);
}

/* Contact Form */
.contact-form {
  background: var(--bg-card);
  border: 1px solid var(--bg-card-border);
  padding: 32px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.form-group label {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  background: var(--bg-primary);
  border: 1px solid var(--bg-card-border);
  color: var(--text-primary);
  transition: all var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-light);
}

.form-group textarea {
  resize: vertical;
}

/* ==========================================================================
   Footer
   ========================================================================== */
.footer {
  background: var(--bg-primary);
  border-top: 1px solid var(--bg-card-border);
  padding: 40px 0;
}

.footer-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.footer-logo {
  font-family: var(--font-code);
  font-size: 1.15rem;
  font-weight: 700;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
  margin-bottom: 6px;
}

.footer-copy {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.back-to-top-btn {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--bg-tertiary);
  border: 1px solid var(--bg-card-border);
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

.back-to-top-btn:hover {
  background: var(--accent-gradient);
  color: #ffffff;
  border-color: transparent;
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

/* ==========================================================================
   Toast Notification
   ========================================================================== */
.toast-container {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 2000;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.toast {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 20px;
  background: var(--bg-card);
  border: 1px solid var(--bg-card-border);
  border-left: 4px solid var(--accent-primary);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-lg);
  backdrop-filter: blur(12px);
  color: var(--text-primary);
  font-size: 0.92rem;
  font-weight: 500;
  animation: slideInRight 0.3s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

.toast.success { border-left-color: #10b981; }
.toast.error { border-left-color: #ef4444; }

@keyframes slideInRight {
  from {
    transform: translateX(100%);
    opacity: 0;
  }
  to {
    transform: translateX(0);
    opacity: 1;
  }
}

/* ==========================================================================
   Animation on Scroll (AOS Utility)
   ========================================================================== */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.8s cubic-bezier(0.16, 1, 0.3, 1), transform 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

.reveal.active {
  opacity: 1;
  transform: translateY(0);
}

/* ==========================================================================
   Responsive Design (Media Queries)
   ========================================================================== */
@media (max-width: 992px) {
  .hero-container {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 40px;
  }

  .hero-description {
    margin-left: auto;
    margin-right: auto;
  }

  .typing-wrapper {
    justify-content: center;
  }

  .hero-cta-group {
    justify-content: center;
  }

  .social-links {
    justify-content: center;
  }

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

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

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

@media (max-width: 768px) {
  :root {
    --nav-height: 64px;
  }

  .section {
    padding: 70px 0;
  }

  .hero-title {
    font-size: 2.35rem;
  }

  .typing-wrapper {
    font-size: 1.15rem;
  }

  .mobile-menu-btn {
    display: flex;
  }

  .nav-menu {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    width: 100%;
    background: var(--bg-primary);
    border-bottom: 1px solid var(--bg-card-border);
    padding: 24px 0;
    box-shadow: var(--shadow-lg);
    transform: translateY(-150%);
    transition: transform var(--transition-normal);
  }

  .nav-menu.open {
    transform: translateY(0);
  }

  .nav-list {
    flex-direction: column;
    gap: 18px;
    text-align: center;
  }

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

  .stat-grid {
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .footer-container {
    flex-direction: column;
    gap: 20px;
    text-align: center;
  }
}