/* ========================================
   Portfolio — Complete Redesign
   Mobile-First | Modern CSS | 3 Themes
   ======================================== */

/* ========================================
   CSS Custom Properties
   ======================================== */
:root {
  /* Night Owl (Default Dark) */
  --bg-primary: #011627;
  --bg-secondary: #0a1f35;
  --bg-card: #0d253f;
  --bg-card-hover: #112d4e;
  --bg-nav: rgba(1, 22, 39, 0.95);

  --text-primary: #d6deeb;
  --text-secondary: #a7abb7;
  --text-muted: #637777;

  --accent-cyan: #7fdbca;
  --accent-purple: #c792ea;
  --accent-yellow: #ffcb6b;
  --accent-blue: #82aaff;
  --accent-red: #ff6369;
  --accent-green: #addb67;
  --accent-orange: #f78c6c;

  --border-subtle: rgba(255, 255, 255, 0.05);
  --border-accent: rgba(127, 219, 202, 0.2);

  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.4);
  --shadow-glow: 0 0 30px rgba(127, 219, 202, 0.1);

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-full: 9999px;

  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-med: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  --ease-out-back: cubic-bezier(0.34, 1.56, 0.64, 1);
  --ease-spring: cubic-bezier(0.22, 1, 0.36, 1);

  --container-max: 1100px;
  --nav-height: 70px;

  /* Responsive type scale */
  --fs-hero-name: clamp(2rem, 5vw + 0.5rem, 3.5rem);
  --fs-hero-title: clamp(1.1rem, 2vw + 0.3rem, 1.6rem);
  --fs-hero-desc: clamp(0.95rem, 1vw + 0.5rem, 1.1rem);
  --fs-section-title: clamp(1.5rem, 3vw + 0.2rem, 2rem);
  --fs-section-sub: clamp(0.9rem, 1vw + 0.4rem, 1.05rem);
  --fs-body: clamp(0.95rem, 0.5vw + 0.65rem, 1.08rem);
  --fs-card-title: clamp(1.1rem, 1.5vw + 0.3rem, 1.3rem);
  --fs-card-desc: clamp(0.88rem, 0.8vw + 0.5rem, 0.98rem);
  --fs-small: clamp(0.78rem, 0.6vw + 0.5rem, 0.88rem);
  --fs-btn: clamp(0.88rem, 0.5vw + 0.6rem, 0.95rem);

  /* Responsive spacing */
  --section-py: clamp(60px, 8vw, 100px);
  --container-px: clamp(16px, 4vw, 24px);
  --gap-xs: 8px;
  --gap-sm: 12px;
  --gap-md: clamp(16px, 2vw, 24px);
  --gap-lg: clamp(24px, 4vw, 40px);
  --gap-xl: clamp(40px, 5vw, 60px);
}

/* ========================================
   Day Theme (Light Mode)
   ======================================== */
[data-theme="day"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #f1f5f9;
  --bg-card: #ffffff;
  --bg-card-hover: #f1f5f9;
  --bg-nav: rgba(248, 250, 252, 0.95);

  --text-primary: #1e293b;
  --text-secondary: #475569;
  --text-muted: #94a3b8;

  --accent-cyan: #0891b2;
  --accent-purple: #9333ea;
  --accent-yellow: #ca8a04;
  --accent-blue: #2563eb;
  --accent-red: #dc2626;
  --accent-green: #16a34a;
  --accent-orange: #ea580c;

  --border-subtle: rgba(0, 0, 0, 0.06);
  --border-accent: rgba(8, 145, 178, 0.2);

  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.1);
  --shadow-glow: 0 0 30px rgba(8, 145, 178, 0.06);
}

/* ========================================
   Tokyo Night Theme
   ======================================== */
[data-theme="tokyo-night"] {
  --bg-primary: #1a1b26;
  --bg-secondary: #1f2335;
  --bg-card: #24283b;
  --bg-card-hover: #292e42;
  --bg-nav: rgba(26, 27, 38, 0.95);

  --text-primary: #c0caf5;
  --text-secondary: #9aa5ce;
  --text-muted: #565f89;

  --accent-cyan: #7dcfff;
  --accent-purple: #bb9af7;
  --accent-yellow: #e0af68;
  --accent-blue: #7aa2f7;
  --accent-red: #f7768e;
  --accent-green: #9ece6a;
  --accent-orange: #ff9e64;

  --border-subtle: rgba(255, 255, 255, 0.06);
  --border-accent: rgba(122, 162, 247, 0.2);

  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 30px rgba(122, 162, 247, 0.1);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-height) + 16px);
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  font-size: var(--fs-body);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color var(--transition-med), color var(--transition-med);
  background-image:
    radial-gradient(ellipse 600px 400px at 20% 10%, rgba(127, 219, 202, 0.04) 0%, transparent 70%),
    radial-gradient(ellipse 500px 350px at 80% 60%, rgba(199, 146, 234, 0.03) 0%, transparent 70%);
}

[data-theme="day"] body {
  background-image:
    radial-gradient(ellipse 600px 400px at 20% 10%, rgba(8, 145, 178, 0.03) 0%, transparent 70%),
    radial-gradient(ellipse 500px 350px at 80% 60%, rgba(147, 51, 234, 0.02) 0%, transparent 70%);
}

[data-theme="tokyo-night"] body {
  background-image:
    radial-gradient(ellipse 600px 400px at 20% 10%, rgba(122, 162, 247, 0.04) 0%, transparent 70%),
    radial-gradient(ellipse 500px 350px at 80% 60%, rgba(187, 154, 247, 0.03) 0%, transparent 70%);
}

::selection {
  background: rgba(127, 219, 202, 0.25);
  color: var(--accent-cyan);
}

[data-theme="day"] ::selection {
  background: rgba(8, 145, 178, 0.2);
  color: var(--accent-cyan);
}

[data-theme="tokyo-night"] ::selection {
  background: rgba(122, 162, 247, 0.25);
  color: var(--accent-cyan);
}

a {
  color: inherit;
  text-decoration: none;
}

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

ul {
  list-style: none;
}

/* ========================================
   Background Glow Effects
   ======================================== */
.bg-glow {
  position: fixed;
  border-radius: 50%;
  pointer-events: none;
  z-index: 0;
  filter: blur(100px);
  opacity: 0.4;
}

.bg-glow-1 {
  width: 600px;
  height: 600px;
  top: -200px;
  left: -150px;
  background: var(--accent-cyan);
  opacity: 0.03;
}

.bg-glow-2 {
  width: 500px;
  height: 500px;
  bottom: -200px;
  right: -150px;
  background: var(--accent-purple);
  opacity: 0.03;
}

[data-theme="day"] .bg-glow-1 { opacity: 0.02; }
[data-theme="day"] .bg-glow-2 { opacity: 0.02; }

[data-theme="tokyo-night"] .bg-glow-1 { opacity: 0.035; }
[data-theme="tokyo-night"] .bg-glow-2 { opacity: 0.035; }

@media (prefers-reduced-motion: reduce) {
  .bg-glow { animation: none; }
}

/* ========================================
   Skip Link (Accessibility)
   ======================================== */
.skip-link {
  position: absolute;
  top: -100%;
  left: 16px;
  z-index: 10000;
  padding: 12px 24px;
  background: var(--accent-cyan);
  color: var(--bg-primary);
  font-weight: 600;
  border-radius: var(--radius-sm);
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: 16px;
  transform: translateY(0);
}

/* ========================================
   Focus States (Accessibility)
   ======================================== */
:focus-visible {
  outline: 2px solid var(--accent-cyan);
  outline-offset: 3px;
  transition: outline-offset var(--transition-fast);
}

button:focus-visible,
a:focus-visible {
  outline: 2px solid var(--accent-cyan);
  outline-offset: 3px;
  transition: outline-offset var(--transition-fast);
}

/* ========================================
   Container
   ======================================== */
.container {
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--container-px);
  width: 100%;
}

/* ========================================
   Buttons (Mobile-First)
   ======================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: clamp(10px, 1.5vw, 14px) clamp(20px, 3vw, 32px);
  border-radius: var(--radius-sm);
  font-size: var(--fs-btn);
  font-weight: 500;
  font-family: inherit;
  line-height: 1.4;
  cursor: pointer;
  border: none;
  transition: all var(--transition-med);
  white-space: nowrap;
  position: relative;
  overflow: hidden;
}

.btn::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at var(--ripple-x, 50%) var(--ripple-y, 50%), rgba(255, 255, 255, 0.2) 0%, transparent 60%);
  opacity: 0;
  transition: opacity 0.4s ease;
  pointer-events: none;
}

.btn:active::after {
  opacity: 1;
  transition: opacity 0s;
}

.btn-primary {
  background: var(--accent-cyan);
  color: var(--bg-primary);
}

.btn-primary:hover {
  filter: brightness(0.9);
  box-shadow: 0 4px 24px rgba(127, 219, 202, 0.35), 0 0 0 1px rgba(127, 219, 202, 0.1);
  transform: translateY(-2px) scale(1.02);
}

.btn-primary:active {
  transform: translateY(0) scale(0.98);
  box-shadow: 0 2px 8px rgba(127, 219, 202, 0.2);
}

.btn-secondary {
  background: transparent;
  color: var(--accent-cyan);
  border: 1.5px solid var(--accent-cyan);
}

.btn-secondary:hover {
  background: rgba(127, 219, 202, 0.1);
  transform: translateY(-2px) scale(1.02);
  box-shadow: 0 4px 20px rgba(127, 219, 202, 0.15);
}

.btn-secondary:active {
  transform: translateY(0) scale(0.98);
}

.btn-card {
  background: rgba(127, 219, 202, 0.1);
  color: var(--accent-cyan);
  padding: clamp(8px, 1vw, 10px) clamp(14px, 2vw, 20px);
  font-size: var(--fs-small);
  border: 1px solid rgba(127, 219, 202, 0.2);
}

.btn-card:hover {
  background: rgba(127, 219, 202, 0.18);
  border-color: rgba(127, 219, 202, 0.4);
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(127, 219, 202, 0.12);
}

.btn-card:active {
  transform: translateY(0) scale(0.98);
}

/* ========================================
   Section Titles
   ======================================== */
.section-title {
  font-size: var(--fs-section-title);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  text-align: center;
  line-height: 1.2;
}

.section-subtitle {
  font-size: var(--fs-section-sub);
  color: var(--text-muted);
  text-align: center;
  margin-top: var(--gap-xs);
}

.accent {
  color: var(--accent-cyan);
}

strong {
  color: var(--accent-cyan);
  font-weight: 600;
}

/* ========================================
   Theme Toggle (Mobile-First)
   ======================================== */
.theme-toggle {
  display: flex;
  align-items: center;
  gap: 4px;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-full);
  padding: 4px 6px;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

[data-theme="day"] .theme-toggle {
  background: rgba(0, 0, 0, 0.04);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.theme-option {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  transition: all var(--transition-fast);
  position: relative;
}

.theme-option:hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.08);
  transform: scale(1.1);
}

.theme-option:active {
  transform: scale(0.92);
}

[data-theme="day"] .theme-option:hover {
  background: rgba(0, 0, 0, 0.08);
}

.theme-option.active {
  color: var(--accent-cyan);
  background: rgba(127, 219, 202, 0.12);
  box-shadow: 0 0 12px rgba(127, 219, 202, 0.1);
}

[data-theme="day"] .theme-option.active {
  background: rgba(8, 145, 178, 0.1);
}

[data-theme="tokyo-night"] .theme-option.active {
  background: rgba(122, 162, 247, 0.15);
}

/* ========================================
   Navigation (Mobile-First)
   ======================================== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: var(--bg-nav);
  backdrop-filter: blur(24px) saturate(1.2);
  -webkit-backdrop-filter: blur(24px) saturate(1.2);
  border-bottom: 1px solid var(--border-subtle);
  transition: background-color var(--transition-med), border-color var(--transition-med), box-shadow var(--transition-med);
}

.navbar.scrolled {
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.15);
}

[data-theme="day"] .navbar.scrolled {
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.06);
}

[data-theme="tokyo-night"] .navbar.scrolled {
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.25);
}

.nav-container {
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--container-px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--nav-height);
}

.nav-logo {
  font-family: 'JetBrains Mono', monospace;
  font-size: clamp(1.2rem, 2vw, 1.4rem);
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
  flex-shrink: 0;
  transition: color var(--transition-fast), transform var(--transition-fast);
}

.nav-logo:hover {
  color: var(--accent-cyan);
  transform: scale(1.05);
}

.nav-menu {
  display: none;
  flex-direction: column;
  gap: 2px;
}

.nav-link {
  display: block;
  padding: 10px 16px;
  font-size: 0.9rem;
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  font-weight: 400;
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 4px;
  left: 50%;
  width: 0;
  height: 2px;
  background: var(--accent-cyan);
  border-radius: 1px;
  transition: width var(--transition-fast), left var(--transition-fast);
  opacity: 0;
}

.nav-link:hover,
.nav-link.active {
  color: var(--accent-cyan);
  background: rgba(127, 219, 202, 0.08);
}

.nav-link:hover::after,
.nav-link.active::after {
  width: 20px;
  left: calc(50% - 10px);
  opacity: 0.6;
}

/* Hamburger Toggle */
.nav-toggle {
  display: flex;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  z-index: 1001;
}

.nav-toggle-bar {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-secondary);
  border-radius: 2px;
  transition: all var(--transition-med) var(--ease-spring);
  transform-origin: center;
}

.nav-toggle.active .nav-toggle-bar:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle.active .nav-toggle-bar:nth-child(2) {
  opacity: 0;
}

.nav-toggle.active .nav-toggle-bar:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* Mobile Menu Overlay */
.nav-menu.active {
  display: flex;
  position: fixed;
  top: var(--nav-height);
  left: 0;
  right: 0;
  background: var(--bg-nav);
  backdrop-filter: blur(24px) saturate(1.2);
  -webkit-backdrop-filter: blur(24px) saturate(1.2);
  padding: var(--gap-sm) var(--container-px) var(--gap-md);
  border-bottom: 1px solid var(--border-subtle);
  z-index: 999;
  animation: slideDown 0.35s var(--ease-spring);
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-12px) scale(0.98);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

.nav-menu.active .nav-link {
  padding: 12px 16px;
  font-size: 1rem;
}

/* ========================================
   Hero Section (Mobile-First)
   ======================================== */
.hero {
  min-height: 100dvh;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: calc(var(--nav-height) + 40px);
  padding-bottom: 40px;
}

.hero-container {
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--container-px);
  width: 100%;
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--gap-xl);
  align-items: center;
}

.hero-content {
  text-align: center;
}

.hero-greeting {
  font-family: 'JetBrains Mono', monospace;
  font-size: clamp(0.85rem, 1.2vw, 1rem);
  color: var(--accent-cyan);
  margin-bottom: var(--gap-sm);
}

.hero-name {
  font-size: var(--fs-hero-name);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: var(--gap-xs);
  color: var(--text-primary);
}

.hero-title {
  font-size: var(--fs-hero-title);
  font-weight: 600;
  color: var(--accent-purple);
  margin-bottom: var(--gap-md);
}

.hero-description {
  font-size: var(--fs-hero-desc);
  color: var(--text-secondary);
  line-height: 1.8;
  max-width: 520px;
  margin-inline: auto;
  margin-bottom: clamp(24px, 4vw, 36px);
}

.hero-buttons {
  display: flex;
  gap: var(--gap-sm);
  flex-wrap: wrap;
  justify-content: center;
}

/* Code Block Decoration */
.hero-decoration {
  display: flex;
  justify-content: center;
  align-items: center;
}

.code-block {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg), 0 0 60px rgba(127, 219, 202, 0.04);
  width: 100%;
  max-width: 440px;
  border: 1px solid var(--border-subtle);
  transition: background-color var(--transition-med), border-color var(--transition-med), box-shadow var(--transition-med), transform var(--transition-med);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}

.code-block:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg), 0 0 80px rgba(127, 219, 202, 0.08);
}

.code-header {
  display: flex;
  gap: 8px;
  padding: 14px 18px;
  background: rgba(0, 0, 0, 0.2);
}

.dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
}

.dot-red { background: var(--accent-red); }
.dot-yellow { background: var(--accent-yellow); }
.dot-green { background: var(--accent-green); }

.code-block pre {
  padding: clamp(16px, 3vw, 24px);
  font-family: 'JetBrains Mono', monospace;
  font-size: clamp(0.72rem, 1vw, 0.85rem);
  line-height: 1.7;
  color: var(--text-primary);
  overflow-x: auto;
}

.code-block code {
  font-family: inherit;
}

.code-block .kw { color: var(--accent-purple); }
.code-block .str { color: var(--accent-green); }
.code-block .fn { color: var(--accent-blue); }

/* ========================================
   Sections
   ======================================== */
.section {
  padding-block: var(--section-py);
}

.section-alt {
  background: var(--bg-secondary);
  transition: background-color var(--transition-med);
}

/* ========================================
   About Section (Mobile-First)
   ======================================== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--gap-lg);
  margin-top: clamp(32px, 5vw, 48px);
}

.about-text p {
  font-size: var(--fs-body);
  color: var(--text-secondary);
  margin-bottom: var(--gap-sm);
  line-height: 1.8;
}

.about-stats {
  display: flex;
  flex-direction: column;
  gap: var(--gap-sm);
}

.stat-card {
  display: flex;
  align-items: center;
  gap: var(--gap-md);
  padding: clamp(16px, 2vw, 20px) clamp(18px, 2.5vw, 24px);
  background: var(--bg-card);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-subtle);
  transition: all var(--transition-med), background-color var(--transition-med), border-color var(--transition-med);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}

.stat-card:hover {
  border-color: var(--border-accent);
  box-shadow: var(--shadow-glow), 0 4px 24px rgba(0, 0, 0, 0.1);
  transform: translateY(-2px);
}

.stat-card:active {
  transform: translateY(0) scale(0.99);
}

.stat-icon {
  color: var(--accent-cyan);
  display: flex;
  align-items: center;
  flex-shrink: 0;
  transition: transform var(--transition-fast);
}

.stat-card:hover .stat-icon {
  transform: scale(1.1);
}

.stat-content {
  display: flex;
  flex-direction: column;
}

.stat-label {
  font-size: var(--fs-small);
  color: var(--text-muted);
}

.stat-value {
  font-size: clamp(0.9rem, 1vw, 1rem);
  font-weight: 600;
  color: var(--text-primary);
}

/* ========================================
   Tech Stack (Mobile-First)
   ======================================== */
.tech-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(clamp(90px, 15vw, 130px), 1fr));
  gap: var(--gap-sm);
  margin-top: clamp(32px, 5vw, 48px);
}

.tech-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: clamp(10px, 1.5vw, 14px);
  padding: clamp(18px, 2.5vw, 28px) clamp(10px, 1.5vw, 16px);
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-subtle);
  transition: all var(--transition-med), background-color var(--transition-med), border-color var(--transition-med);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  position: relative;
  overflow: hidden;
}

.tech-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 50% 0%, rgba(127, 219, 202, 0.06) 0%, transparent 70%);
  opacity: 0;
  transition: opacity var(--transition-med);
  pointer-events: none;
}

.tech-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-accent);
  box-shadow: var(--shadow-glow), 0 8px 32px rgba(0, 0, 0, 0.12);
}

.tech-card:hover::before {
  opacity: 1;
}

.tech-card:active {
  transform: translateY(-2px) scale(0.98);
}

.tech-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform var(--transition-fast) var(--ease-spring);
}

.tech-card:hover .tech-icon {
  transform: scale(1.15) rotate(3deg);
}

.tech-name {
  font-size: clamp(0.8rem, 1vw, 0.9rem);
  font-weight: 500;
  color: var(--text-secondary);
}

/* ========================================
   Projects (Mobile-First)
   ======================================== */
.projects-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--gap-md);
  margin-top: clamp(32px, 5vw, 48px);
}

.project-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: clamp(24px, 3vw, 32px);
  border: 1px solid var(--border-subtle);
  transition: all var(--transition-med), background-color var(--transition-med), border-color var(--transition-med);
  display: flex;
  flex-direction: column;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  position: relative;
  overflow: hidden;
}

.project-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--accent-cyan), transparent);
  opacity: 0;
  transition: opacity var(--transition-med);
}

.project-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-accent);
  box-shadow: var(--shadow-glow), 0 12px 40px rgba(0, 0, 0, 0.12);
}

.project-card:hover::before {
  opacity: 0.6;
}

.project-card:active {
  transform: translateY(-2px) scale(0.99);
}

.project-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: clamp(16px, 2vw, 24px);
}

.project-icon {
  color: var(--accent-cyan);
  display: flex;
  align-items: center;
}

.project-link {
  color: var(--text-muted);
  transition: color var(--transition-fast), transform var(--transition-fast);
}

.project-link:hover {
  color: var(--accent-cyan);
  transform: translate(2px, -2px);
}

.project-title {
  font-size: var(--fs-card-title);
  font-weight: 600;
  margin-bottom: var(--gap-xs);
  color: var(--text-primary);
}

.project-description {
  font-size: var(--fs-card-desc);
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: var(--gap-sm);
  flex-grow: 1;
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--gap-xs);
  margin-bottom: clamp(16px, 2vw, 24px);
}

.tag {
  padding: 4px 14px;
  background: rgba(127, 219, 202, 0.08);
  color: var(--accent-cyan);
  border-radius: var(--radius-full);
  font-size: var(--fs-small);
  font-weight: 500;
  border: 1px solid rgba(127, 219, 202, 0.12);
  transition: all var(--transition-fast);
}

.tag:hover {
  background: rgba(127, 219, 202, 0.15);
  transform: scale(1.05);
}

/* ========================================
   Learning (Mobile-First)
   ======================================== */
.learning-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--gap-md);
  margin-top: clamp(32px, 5vw, 48px);
}

.learning-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: clamp(28px, 4vw, 36px) clamp(20px, 3vw, 28px);
  text-align: center;
  border: 1px solid var(--border-subtle);
  transition: all var(--transition-med), background-color var(--transition-med), border-color var(--transition-med);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  position: relative;
  overflow: hidden;
}

.learning-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 50% 100%, rgba(199, 146, 234, 0.06) 0%, transparent 70%);
  opacity: 0;
  transition: opacity var(--transition-med);
  pointer-events: none;
}

.learning-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-accent);
  box-shadow: var(--shadow-glow), 0 12px 40px rgba(0, 0, 0, 0.12);
}

.learning-card:hover::before {
  opacity: 1;
}

.learning-card:active {
  transform: translateY(-2px) scale(0.99);
}

.learning-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--gap-sm);
  transition: transform var(--transition-fast) var(--ease-spring);
}

.learning-card:hover .learning-icon {
  transform: scale(1.12) translateY(-2px);
}

.learning-name {
  font-size: var(--fs-card-title);
  font-weight: 600;
  margin-bottom: var(--gap-xs);
  color: var(--text-primary);
}

.learning-desc {
  font-size: var(--fs-card-desc);
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ========================================
   Focus Areas (Mobile-First)
   ======================================== */
.focus-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(clamp(140px, 30vw, 200px), 1fr));
  gap: var(--gap-sm);
  margin-top: clamp(32px, 5vw, 48px);
}

.focus-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: clamp(24px, 3vw, 32px) clamp(16px, 2vw, 24px);
  text-align: center;
  border: 1px solid var(--border-subtle);
  transition: all var(--transition-med), background-color var(--transition-med), border-color var(--transition-med);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  position: relative;
  overflow: hidden;
}

.focus-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 50% 0%, rgba(127, 219, 202, 0.05) 0%, transparent 70%);
  opacity: 0;
  transition: opacity var(--transition-med);
  pointer-events: none;
}

.focus-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-accent);
  box-shadow: var(--shadow-glow), 0 8px 32px rgba(0, 0, 0, 0.12);
}

.focus-card:hover::before {
  opacity: 1;
}

.focus-card:active {
  transform: translateY(-2px) scale(0.99);
}

.focus-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--gap-sm);
  transition: transform var(--transition-fast) var(--ease-spring);
}

.focus-card:hover .focus-icon {
  transform: scale(1.15) translateY(-2px);
}

.focus-name {
  font-size: clamp(0.92rem, 1.2vw, 1.05rem);
  font-weight: 600;
  margin-bottom: var(--gap-xs);
  color: var(--text-primary);
}

.focus-desc {
  font-size: var(--fs-card-desc);
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ========================================
   GitHub Stats (Mobile-First)
   ======================================== */
.github-grid {
  display: flex;
  justify-content: center;
  margin-top: clamp(32px, 5vw, 48px);
  margin-bottom: var(--gap-lg);
}

.github-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: clamp(16px, 2vw, 24px);
  border: 1px solid var(--border-subtle);
  max-width: 500px;
  width: 100%;
  transition: background-color var(--transition-med), border-color var(--transition-med), transform var(--transition-med), box-shadow var(--transition-med);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}

.github-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-glow), 0 8px 32px rgba(0, 0, 0, 0.1);
}

.github-card img {
  border-radius: var(--radius-sm);
  width: 100%;
  height: auto;
}

.github-profile {
  text-align: center;
}

/* ========================================
   Contact (Mobile-First)
   ======================================== */
.contact-content {
  text-align: center;
  max-width: 600px;
  margin-inline: auto;
  margin-top: clamp(32px, 5vw, 48px);
}

.contact-text {
  font-size: clamp(1rem, 1.2vw, 1.15rem);
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: clamp(28px, 4vw, 40px);
}

.contact-methods {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--gap-sm);
}

.contact-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--gap-xs);
  padding: clamp(20px, 3vw, 28px) clamp(28px, 4vw, 36px);
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-subtle);
  transition: all var(--transition-med), background-color var(--transition-med), border-color var(--transition-med);
  width: 100%;
  max-width: 300px;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  position: relative;
  text-decoration: none;
}

a.contact-card {
  cursor: pointer;
}

.contact-link {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--gap-xs);
  color: inherit;
  text-decoration: none;
  flex: 1;
}

.contact-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-accent);
  box-shadow: var(--shadow-glow), 0 8px 32px rgba(0, 0, 0, 0.1);
}

.contact-card:active {
  transform: translateY(0) scale(0.98);
}

.contact-card svg {
  transition: transform var(--transition-fast) var(--ease-spring);
}

.contact-card:hover svg {
  transform: scale(1.1) translateY(-2px);
}

.contact-label {
  font-size: var(--fs-small);
  font-weight: 600;
  color: var(--text-primary);
}

.contact-address {
  font-size: var(--fs-small);
  color: var(--text-muted);
  font-family: 'JetBrains Mono', monospace;
  word-break: break-all;
}

/* ========================================
   Footer (Mobile-First)
   ======================================== */
.footer {
  padding-block: clamp(28px, 4vw, 40px);
  border-top: 1px solid var(--border-subtle);
  transition: border-color var(--transition-med);
  background: linear-gradient(180deg, transparent 0%, rgba(127, 219, 202, 0.02) 100%);
}

[data-theme="day"] .footer {
  background: linear-gradient(180deg, transparent 0%, rgba(8, 145, 178, 0.015) 100%);
}

[data-theme="tokyo-night"] .footer {
  background: linear-gradient(180deg, transparent 0%, rgba(122, 162, 247, 0.02) 100%);
}

.footer-content {
  text-align: center;
}

.footer-text {
  font-size: clamp(0.85rem, 1vw, 0.9rem);
  color: var(--text-secondary);
  margin-bottom: 6px;
}

.footer-copyright {
  font-size: var(--fs-small);
  color: var(--text-muted);
}

/* ========================================
   Fade-in Animation
   ======================================== */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s var(--ease-spring), transform 0.7s var(--ease-spring);
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Staggered delays for child elements */
.fade-in[data-delay="1"] { transition-delay: 0.08s; }
.fade-in[data-delay="2"] { transition-delay: 0.16s; }
.fade-in[data-delay="3"] { transition-delay: 0.24s; }
.fade-in[data-delay="4"] { transition-delay: 0.32s; }
.fade-in[data-delay="5"] { transition-delay: 0.4s; }
.fade-in[data-delay="6"] { transition-delay: 0.48s; }
.fade-in[data-delay="7"] { transition-delay: 0.56s; }

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

  .fade-in {
    opacity: 1;
    transform: none;
  }

  .fade-in[data-delay] {
    transition-delay: 0s;
  }

  .btn:hover,
  .tech-card:hover,
  .project-card:hover,
  .learning-card:hover,
  .focus-card:hover,
  .contact-card:hover,
  .stat-card:hover,
  .code-block:hover,
  .github-card:hover {
    transform: none;
  }

  .btn:active,
  .tech-card:active,
  .project-card:active,
  .learning-card:active,
  .focus-card:active,
  .contact-card:active,
  .stat-card:active,
  .code-block:active,
  .github-card:active {
    transform: none;
  }

  .nav-logo:hover,
  .project-link:hover,
  .tag:hover,
  .theme-option:hover,
  .theme-option:active,
  .contact-card:hover svg,
  .tech-card:hover .tech-icon,
  .learning-card:hover .learning-icon,
  .focus-card:hover .focus-icon,
  .stat-card:hover .stat-icon {
    transform: none;
  }

  .nav-link::after {
    display: none;
  }

  .hero-cursor {
    animation: none;
    opacity: 1;
  }

  .back-to-top {
    transition: opacity 0.01ms, visibility 0.01ms;
  }

  .copy-toast {
    transition: opacity 0.01ms, visibility 0.01ms, transform 0.01ms;
  }
}

/* ========================================
   Scroll Progress Bar
   ======================================== */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0%;
  background: linear-gradient(90deg, var(--accent-cyan), var(--accent-purple));
  z-index: 1001;
  transition: none;
  will-change: width;
}

/* ========================================
   Back to Top Button
   ======================================== */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  z-index: 900;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: 1px solid var(--border-accent);
  background: var(--bg-card);
  color: var(--accent-cyan);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px) scale(0.9);
  transition: all var(--transition-med) var(--ease-spring),
              background-color var(--transition-med),
              border-color var(--transition-med);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: var(--shadow-md);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0) scale(1);
}

.back-to-top:hover {
  background: var(--accent-cyan);
  color: var(--bg-primary);
  transform: translateY(-4px) scale(1.08);
  box-shadow: 0 8px 32px rgba(127, 219, 202, 0.3);
}

.back-to-top:active {
  transform: translateY(0) scale(0.95);
}

[data-theme="day"] .back-to-top:hover {
  box-shadow: 0 8px 32px rgba(8, 145, 178, 0.25);
}

[data-theme="tokyo-night"] .back-to-top:hover {
  box-shadow: 0 8px 32px rgba(122, 162, 247, 0.3);
}

/* ========================================
   Copy Email Toast
   ======================================== */
.copy-toast {
  position: fixed;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--accent-cyan);
  color: var(--bg-primary);
  padding: 10px 24px;
  border-radius: var(--radius-full);
  font-size: var(--fs-small);
  font-weight: 600;
  z-index: 2000;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-med) var(--ease-spring);
  box-shadow: 0 8px 32px rgba(127, 219, 202, 0.3);
  pointer-events: none;
}

.copy-toast.show {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
}

/* ========================================
   Copy Button (inside contact card)
   ======================================== */
.copy-btn {
  position: absolute;
  top: 12px;
  right: 12px;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-subtle);
  background: var(--bg-secondary);
  color: var(--text-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: all var(--transition-fast);
  z-index: 2;
}

.contact-card {
  position: relative;
}

.contact-card:hover .copy-btn {
  opacity: 1;
}

.copy-btn:hover {
  color: var(--accent-cyan);
  border-color: var(--border-accent);
  background: var(--bg-card);
}

.copy-btn:active {
  transform: scale(0.9);
}

/* ========================================
   Hero Cursor Blink
   ======================================== */
.hero-cursor {
  display: inline-block;
  width: 2px;
  height: 1.1em;
  background: var(--accent-cyan);
  margin-left: 4px;
  vertical-align: text-bottom;
  animation: cursorBlink 1.1s step-end infinite;
}

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

/* ========================================
   Enhanced Glassmorphism (cards)
   ======================================== */
.tech-card,
.project-card,
.learning-card,
.focus-card,
.stat-card,
.contact-card,
.github-card,
.code-block {
  background: color-mix(in srgb, var(--bg-card) 85%, transparent);
  border: 1px solid color-mix(in srgb, var(--border-subtle) 80%, transparent);
}

/* ========================================
   Section Divider Gradient
   ======================================== */
.section + .section:not(.section-alt)::before,
.section-alt + .section::before {
  content: '';
  display: block;
  width: 80px;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--accent-cyan), transparent);
  margin: 0 auto;
  opacity: 0.3;
}

/* ========================================
   Hero Name Gradient
   ======================================== */
.hero-name {
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-cyan) 50%, var(--accent-purple) 100%);
  background-size: 200% auto;
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

[data-theme="day"] .hero-name {
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-cyan) 60%, var(--accent-purple) 100%);
  background-size: 200% auto;
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* ========================================
   Subtle Card Top Glow on Hover
   ======================================== */
.tech-card::after,
.learning-card::after,
.focus-card::after {
  content: '';
  position: absolute;
  top: -1px;
  left: 20%;
  right: 20%;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent-cyan), transparent);
  opacity: 0;
  transition: opacity var(--transition-med);
  pointer-events: none;
}

.tech-card:hover::after,
.learning-card:hover::after,
.focus-card:hover::after {
  opacity: 0.6;
}

/* ========================================
   Nav Active Pill Style
   ======================================== */
.nav-link.active {
  background: rgba(127, 219, 202, 0.1);
  color: var(--accent-cyan);
  font-weight: 500;
}

[data-theme="day"] .nav-link.active {
  background: rgba(8, 145, 178, 0.08);
}

[data-theme="tokyo-night"] .nav-link.active {
  background: rgba(122, 162, 247, 0.1);
}

/* ========================================
   Breakpoint: 480px (Large Phones)
   ======================================== */
@media (min-width: 480px) {
  .hero-buttons {
    flex-direction: row;
  }

  .btn {
    flex: 0 1 auto;
  }

  .tech-grid {
    grid-template-columns: repeat(auto-fit, minmax(110px, 1fr));
  }

  .contact-methods {
    flex-direction: row;
    justify-content: center;
    flex-wrap: wrap;
  }

  .contact-card {
    flex: 0 1 auto;
  }

  .focus-grid {
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  }

  .back-to-top {
    bottom: 28px;
    right: 28px;
    width: 44px;
    height: 44px;
  }
}

/* ========================================
   Breakpoint: 768px (Tablets)
   ======================================== */
@media (min-width: 768px) {
  :root {
    --nav-height: 72px;
  }

  /* Navigation: Desktop layout */
  .nav-toggle {
    display: none;
  }

  .nav-menu {
    display: flex;
    flex-direction: row;
    position: static;
    background: none;
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
    padding: 0;
    border: none;
    gap: var(--gap-xs);
  }

  .nav-link {
    font-size: 0.88rem;
    padding: 8px 14px;
  }

  /* Hero: Two-column layout */
  .hero-container {
    grid-template-columns: 1fr 1fr;
    text-align: start;
  }

  .hero-content {
    text-align: start;
  }

  .hero-description {
    margin-inline: 0;
  }

  .hero-buttons {
    justify-content: flex-start;
  }

  .hero-decoration {
    order: 0;
  }

  /* About: Two-column layout */
  .about-grid {
    grid-template-columns: 1.2fr 1fr;
    gap: var(--gap-xl);
    align-items: start;
  }

  /* Projects: Two-column */
  .projects-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  /* Learning: Three-column */
  .learning-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* ========================================
   Breakpoint: 1024px (Small Laptops)
   ======================================== */
@media (min-width: 1024px) {
  .tech-grid {
    grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
    gap: var(--gap-md);
  }

  .focus-grid {
    grid-template-columns: repeat(5, 1fr);
    gap: var(--gap-md);
  }

  .code-block {
    max-width: 440px;
  }
}

/* ========================================
   Breakpoint: 1280px (Desktops)
   ======================================== */
@media (min-width: 1280px) {
  :root {
    --container-max: 1200px;
  }

  .hero {
    padding-top: calc(var(--nav-height) + 60px);
  }

  .tech-grid {
    grid-template-columns: repeat(7, 1fr);
  }
}

/* ========================================
   Breakpoint: 1440px (Large Desktops)
   ======================================== */
@media (min-width: 1440px) {
  :root {
    --container-max: 1300px;
  }
}

/* ========================================
   Breakpoint: 1920px (Ultra-Wide)
   ======================================== */
@media (min-width: 1920px) {
  :root {
    --container-max: 1400px;
  }
}