/* ========== CSS Variables ========== */
:root {
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-bg: #ffffff;
  --color-bg-secondary: #f9fafb;
  --color-surface: #ffffff;
  --color-text: #111827;
  --color-text-secondary: #6b7280;
  --color-border: #e5e7eb;
  --color-nav-bg: rgba(255, 255, 255, 0.88);
  --radius: 12px;
  --radius-sm: 8px;
  --radius-pill: 999px;
  --max-width: 720px;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
  --transition: 0.2s ease;
  --transition-slow: 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
  --logo-color: #38bdf8;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  transition: background var(--transition), color var(--transition);
  background:
    /* Noise texture — tiny random-looking dots */
    radial-gradient(circle 0.5px at 10% 20%, rgba(0, 0, 0, 0.03) 0.5px, transparent 0.5px),
    radial-gradient(circle 0.5px at 40% 70%, rgba(0, 0, 0, 0.02) 0.5px, transparent 0.5px),
    radial-gradient(circle 0.5px at 70% 30%, rgba(0, 0, 0, 0.03) 0.5px, transparent 0.5px),
    radial-gradient(circle 0.5px at 25% 85%, rgba(0, 0, 0, 0.02) 0.5px, transparent 0.5px),
    radial-gradient(circle 0.5px at 85% 55%, rgba(0, 0, 0, 0.03) 0.5px, transparent 0.5px),
    /* Glow — top: soft blue */
    radial-gradient(ellipse 800px 600px at 25% 5%, rgba(191, 219, 254, 0.3), transparent 70%),
    /* Glow — middle: soft purple */
    radial-gradient(ellipse 700px 500px at 75% 50%, rgba(221, 214, 254, 0.22), transparent 70%),
    /* Glow — bottom: soft blue-indigo */
    radial-gradient(ellipse 600px 500px at 40% 90%, rgba(199, 210, 254, 0.2), transparent 70%),
    /* Base gradient */
    linear-gradient(180deg, #ffffff 0%, #f5f7fa 50%, #f0f2f8 100%);
  background-size:
    3px 3px, 4px 4px, 3px 3px, 4px 4px, 3px 3px,
    auto, auto, auto, auto;
  background-attachment: fixed;
}

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

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

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

/* ========== Navbar ========== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 200;
  background: var(--color-nav-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--color-border);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 56px;
}

.nav-logo {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--logo-color);
}

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


.nav-links {
  display: flex;
  list-style: none;
  gap: 24px;
}

.nav-links a {
  position: relative;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  transition: color var(--transition);
  padding-bottom: 2px;
}

.nav-links a::after {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 1.5px;
  background: var(--color-primary);
  transition: width var(--transition-slow);
}

.nav-links a:hover {
  color: var(--color-text);
}

.nav-links a:hover::after {
  width: 100%;
}

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

.nav-links a.active::after {
  width: 100%;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 16px 4px 4px;
  align-self: flex-start;
}

.nav-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

/* ========== Hero ========== */
.hero {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  text-align: center;
  padding: 120px 24px 80px;
}

.hero-avatar {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  object-fit: cover;
  margin-bottom: 24px;
  box-shadow: 0 8px 24px rgba(37, 99, 235, 0.25), 0 4px 10px rgba(0, 0, 0, 0.08);
  animation: float 3.5s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

.hero-name {
  font-size: 2.5rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 8px;
}

.hero-tagline {
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  max-width: 480px;
}

/* ========== Typewriter Cursor ========== */
.typewriter-cursor {
  display: inline-block;
  margin-left: 2px;
  font-weight: 300;
  color: var(--color-primary);
  animation: blink 0.7s step-end infinite;
}

@keyframes blink {
  50% { opacity: 0; }
}

/* ========== Sections ========== */
.section {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 80px 24px;
}

.section-title {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: 24px;
}

.section-body {
  color: var(--color-text-secondary);
  font-size: 1rem;
  line-height: 1.8;
}

/* ========== Skill Tags ========== */
.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.pill {
  display: inline-block;
  padding: 6px 16px;
  font-size: 0.875rem;
  font-weight: 500;
  background: var(--color-bg-secondary);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  cursor: default;
  transition: background var(--transition), border-color var(--transition), color var(--transition), transform var(--transition), box-shadow var(--transition);
}

.pill:hover {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
  transform: translateY(-1px);
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.25);
}

/* ========== Project Grid ========== */
.project-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.project-card {
  position: relative;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 24px 24px 24px 28px;
  overflow: hidden;
  transition: box-shadow var(--transition-slow), transform var(--transition-slow), border-color var(--transition);
}

.project-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 100%;
  background: var(--color-primary);
  opacity: 0.6;
  transition: opacity var(--transition);
}

.project-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-3px);
  border-color: transparent;
}

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

.project-card h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.project-card p {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  margin-bottom: 12px;
}

.card-link {
  font-size: 0.875rem;
  font-weight: 500;
  transition: color var(--transition), gap var(--transition);
}

/* ========== Contact ========== */
.contact-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.contact-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 24px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  transition: background var(--transition), border-color var(--transition), box-shadow var(--transition), color var(--transition);
}

.contact-btn svg {
  flex-shrink: 0;
}

.contact-btn::after {
  content: "";
  position: absolute;
  bottom: 6px;
  left: 24px;
  right: 24px;
  height: 1px;
  background: currentColor;
  opacity: 0;
  transform: scaleX(0);
  transform-origin: left;
  transition: opacity var(--transition), transform var(--transition-slow);
}

.contact-btn {
  position: relative;
}

.contact-btn:hover {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
  box-shadow: var(--shadow-sm);
}

.contact-btn:hover::after {
  opacity: 0.5;
  transform: scaleX(1);
}

/* ========== Footer ========== */
.footer {
  text-align: center;
  padding: 32px 24px;
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
  border-top: 1px solid var(--color-border);
}

/* ========== Back to Top ========== */
.back-to-top {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 50;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 50%;
  cursor: pointer;
  box-shadow: var(--shadow-md);
  opacity: 0;
  pointer-events: none;
  transform: translateY(8px);
  color: var(--color-text-secondary);
  transition: opacity var(--transition-slow), transform var(--transition-slow), color var(--transition), border-color var(--transition), box-shadow var(--transition);
}

.back-to-top.visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

.back-to-top:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  box-shadow: var(--shadow-lg);
}

/* ========== Scroll Reveal Animations ========== */
@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s cubic-bezier(0.4, 0, 0.2, 1), transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

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

.reveal.visible .section-title {
  animation: fadeIn 0.5s ease both;
}

.reveal.visible .pill,
.reveal.visible .project-card,
.reveal.visible .contact-btn {
  animation: slideUp 0.4s cubic-bezier(0.4, 0, 0.2, 1) both;
}

/* Stagger children */
.reveal.visible .pill:nth-child(1),
.reveal.visible .project-card:nth-child(1),
.reveal.visible .contact-btn:nth-child(1) { animation-delay: 0.05s; }
.reveal.visible .pill:nth-child(2),
.reveal.visible .project-card:nth-child(2),
.reveal.visible .contact-btn:nth-child(2) { animation-delay: 0.1s; }
.reveal.visible .pill:nth-child(3),
.reveal.visible .project-card:nth-child(3),
.reveal.visible .contact-btn:nth-child(3) { animation-delay: 0.15s; }
.reveal.visible .pill:nth-child(4),
.reveal.visible .project-card:nth-child(4) { animation-delay: 0.2s; }
.reveal.visible .pill:nth-child(5) { animation-delay: 0.25s; }
.reveal.visible .pill:nth-child(6) { animation-delay: 0.3s; }
.reveal.visible .pill:nth-child(7) { animation-delay: 0.35s; }
.reveal.visible .pill:nth-child(8) { animation-delay: 0.4s; }

/* ========== Dark Mode ========== */
[data-theme="dark"] {
  --color-primary: #3b82f6;
  --color-primary-hover: #60a5fa;
  --color-bg: #0f172a;
  --logo-color: #7dd3fc;
  --color-bg-secondary: #1e293b;
  --color-surface: #1e293b;
  --color-text: #e2e8f0;
  --color-text-secondary: #94a3b8;
  --color-border: #334155;
  --color-nav-bg: rgba(15, 23, 42, 0.88);
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);
}

[data-theme="dark"] body {
  background:
    radial-gradient(circle 0.5px at 10% 20%, rgba(255, 255, 255, 0.03) 0.5px, transparent 0.5px),
    radial-gradient(circle 0.5px at 40% 70%, rgba(255, 255, 255, 0.02) 0.5px, transparent 0.5px),
    radial-gradient(circle 0.5px at 70% 30%, rgba(255, 255, 255, 0.03) 0.5px, transparent 0.5px),
    radial-gradient(circle 0.5px at 25% 85%, rgba(255, 255, 255, 0.02) 0.5px, transparent 0.5px),
    radial-gradient(circle 0.5px at 85% 55%, rgba(255, 255, 255, 0.03) 0.5px, transparent 0.5px),
    radial-gradient(ellipse 800px 600px at 25% 5%, rgba(59, 130, 246, 0.15), transparent 70%),
    radial-gradient(ellipse 700px 500px at 75% 50%, rgba(139, 92, 246, 0.12), transparent 70%),
    radial-gradient(ellipse 600px 500px at 40% 90%, rgba(99, 102, 241, 0.1), transparent 70%),
    linear-gradient(180deg, #0f172a 0%, #0f172a 50%, #0f172a 100%);
  background-size: 3px 3px, 4px 4px, 3px 3px, 4px 4px, 3px 3px, auto, auto, auto, auto;
  background-attachment: fixed;
}

[data-theme="dark"] .hero-avatar {
  box-shadow: 0 8px 28px rgba(59, 130, 246, 0.35), 0 4px 12px rgba(0, 0, 0, 0.4);
}

[data-theme="dark"] .pill:hover {
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.35);
}

[data-theme="dark"] .project-card:hover {
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.5);
}

[data-theme="dark"] .nav-links {
  background: rgba(15, 23, 42, 0.95);
}

[data-theme="dark"] .contact-btn:hover {
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.3);
}

/* ========== Theme Toggle ========== */
.theme-toggle {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 50%;
  cursor: pointer;
  color: var(--color-text-secondary);
  box-shadow: var(--shadow-md);
  transition: bottom 0.3s ease, color var(--transition), border-color var(--transition), background var(--transition), box-shadow var(--transition);
}

.theme-toggle.shifted {
  bottom: 76px;
}

.theme-toggle:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  box-shadow: var(--shadow-lg);
}

.theme-toggle svg {
  width: 18px;
  height: 18px;
}

.theme-toggle .icon-sun,
[data-theme="dark"] .theme-toggle .icon-moon {
  display: block;
}

.theme-toggle .icon-moon,
[data-theme="dark"] .theme-toggle .icon-sun {
  display: none;
}

/* ========== Responsive ========== */
@media (max-width: 600px) {
  .nav-toggle {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: 56px;
    left: 0;
    right: 0;
    z-index: 99;
    flex-direction: column;
    gap: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border-bottom: 1px solid var(--color-border);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
    padding: 0;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
  }

  .nav-links.open {
    max-height: 240px;
    padding: 8px 0;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
  }

  .nav-links li a {
    display: block;
    padding: 14px 24px;
    font-size: 1rem;
    border-bottom: 1px solid var(--color-border);
  }

  .nav-links li:last-child a {
    border-bottom: none;
  }

  .nav-links a::after {
    display: none;
  }

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

  .hero {
    padding: 100px 20px 60px;
    min-height: auto;
  }

  .hero-avatar {
    width: 96px;
    height: 96px;
  }

  .hero-name {
    font-size: 1.875rem;
  }

  .hero-tagline {
    font-size: 1rem;
  }

  .section {
    padding: 48px 20px;
  }

  .section-title {
    font-size: 1.25rem;
    margin-bottom: 20px;
  }

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

  .project-card {
    padding: 20px 20px 20px 24px;
  }

  .contact-btn {
    padding: 10px 20px;
    font-size: 0.8125rem;
  }
}