/* ===== CSS Custom Properties ===== */
:root {
  --bg-primary: #FAFAFA;
  --bg-secondary: rgba(255, 255, 255, 0.5);
  --bg-card: #FFFFFF;
  --text-primary: #1A1A2E;
  --text-secondary: #4A4A6A;
  --accent: #2563EB;
  --accent-hover: #1D4ED8;
  --accent-light: #DBEAFE;
  --border: #E2E8F0;
  --shadow: rgba(0, 0, 0, 0.08);
  --tag-bg: #F1F5F9;
  --nav-bg: rgba(255, 255, 255, 0.9);
  --font-sans: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;
}

[data-theme="dark"] {
  --bg-primary: #0F172A;
  --bg-secondary: rgba(30, 41, 59, 0.5);
  --bg-card: #1E293B;
  --text-primary: #E2E8F0;
  --text-secondary: #94A3B8;
  --accent: #3B82F6;
  --accent-hover: #60A5FA;
  --accent-light: #1E3A5F;
  --border: #334155;
  --shadow: rgba(0, 0, 0, 0.3);
  --tag-bg: #334155;
  --nav-bg: rgba(15, 23, 42, 0.9);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 5rem;
  overflow-x: hidden;
}

body {
  font-family: var(--font-sans);
  font-size: clamp(1rem, 1.5vw, 1.125rem);
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  transition: background-color 0.3s ease, color 0.3s ease;
}

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

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s ease;
}

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

ul {
  list-style: none;
}

/* ===== Focus ===== */
*:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* ===== Background Animation ===== */
.bg-animation {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  overflow: hidden;
}

.bg-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  transition: background 0.6s ease;
}

.bg-orb-1 {
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, #93c5fd, #6366f1);
  top: -10%;
  left: -5%;
}

.bg-orb-2 {
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, #a78bfa, #3b82f6);
  top: 50%;
  right: -10%;
}

.bg-orb-3 {
  width: 350px;
  height: 350px;
  background: radial-gradient(circle, #67e8f9, #6366f1);
  bottom: -5%;
  left: 30%;
}

[data-theme="dark"] .bg-orb {
  opacity: 0.75;
}

[data-theme="dark"] .bg-orb-1 {
  background: radial-gradient(circle, #1e40af, #4338ca);
}

[data-theme="dark"] .bg-orb-2 {
  background: radial-gradient(circle, #5b21b6, #1d4ed8);
}

[data-theme="dark"] .bg-orb-3 {
  background: radial-gradient(circle, #0e7490, #4338ca);
}

@media (prefers-reduced-motion: no-preference) {
  .bg-orb-1 {
    animation: drift1 20s ease-in-out infinite;
  }

  .bg-orb-2 {
    animation: drift2 25s ease-in-out infinite;
  }

  .bg-orb-3 {
    animation: drift3 18s ease-in-out infinite;
  }
}

@keyframes drift1 {
  0%, 100% { transform: translate(0, 0); }
  25% { transform: translate(80px, 60px); }
  50% { transform: translate(40px, 120px); }
  75% { transform: translate(-30px, 50px); }
}

@keyframes drift2 {
  0%, 100% { transform: translate(0, 0); }
  25% { transform: translate(-60px, -40px); }
  50% { transform: translate(-100px, 30px); }
  75% { transform: translate(-20px, -70px); }
}

@keyframes drift3 {
  0%, 100% { transform: translate(0, 0); }
  25% { transform: translate(50px, -50px); }
  50% { transform: translate(-40px, -80px); }
  75% { transform: translate(70px, -20px); }
}

/* ===== Skip Link ===== */
.skip-link {
  position: absolute;
  top: -100%;
  left: 1rem;
  background: var(--accent);
  color: #fff;
  padding: 0.5rem 1rem;
  border-radius: 0 0 8px 8px;
  z-index: 2000;
  font-weight: 600;
}

.skip-link:focus {
  top: 0;
}

/* ===== Container ===== */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ===== Navigation ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--nav-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: background 0.3s ease, border-color 0.3s ease;
}

.site-header nav {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4rem;
}

.nav-logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

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

.nav-links {
  display: flex;
  gap: 2rem;
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  padding: 0.25rem 0;
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: width 0.3s ease;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--accent);
}

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

/* Theme toggle */
#theme-toggle {
  background: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.4rem;
  cursor: pointer;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: color 0.2s ease, border-color 0.2s ease;
}

#theme-toggle:hover {
  color: var(--accent);
  border-color: var(--accent);
}

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

/* Hamburger */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.hamburger {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  position: relative;
  transition: background 0.3s ease;
}

.hamburger::before,
.hamburger::after {
  content: '';
  position: absolute;
  left: 0;
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  transition: transform 0.3s ease;
}

.hamburger::before { top: -7px; }
.hamburger::after { top: 7px; }

.nav-toggle[aria-expanded="true"] .hamburger {
  background: transparent;
}

.nav-toggle[aria-expanded="true"] .hamburger::before {
  transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle[aria-expanded="true"] .hamburger::after {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* ===== Buttons ===== */
.btn {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  padding: 0.75rem 1.5rem;
  border-radius: 8px;
  border: none;
  cursor: pointer;
  transition: all 0.2s ease;
  text-align: center;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--accent-hover);
  color: #fff;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

.btn-outline {
  background: transparent;
  color: var(--accent);
  border: 1px solid var(--accent);
}

.btn-outline:hover {
  background: var(--accent);
  color: #fff;
}

/* ===== Hero / About ===== */
.hero {
  min-height: 75vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 6rem 1.5rem 4rem;
}

.hero-content {
  max-width: 700px;
  text-align: center;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.2;
  margin-bottom: 0.75rem;
}

.accent {
  background: linear-gradient(135deg, var(--accent), #8b5cf6);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.tagline {
  font-size: clamp(1.1rem, 2.5vw, 1.4rem);
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  min-height: 2rem;
}

.bio {
  color: var(--text-secondary);
  max-width: 540px;
  margin: 0 auto 2rem;
}

/* Typing animation */
.typing {
  display: inline-block;
  border-right: 2px solid var(--accent);
  white-space: nowrap;
  overflow: hidden;
  width: 0;
}

/* ===== Sections ===== */
section {
  padding: 5rem 0;
  position: relative;
}

section + section::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: min(200px, 40%);
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent), transparent);
  opacity: 0.3;
}

section h2 {
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  font-weight: 700;
  text-align: center;
  margin-bottom: 0.5rem;
  letter-spacing: -0.02em;
}

.section-subtitle {
  text-align: center;
  color: var(--text-secondary);
  margin-bottom: 3rem;
  max-width: 500px;
  margin-left: auto;
  margin-right: auto;
}

#projects h2,
#skills h2 {
  margin-bottom: 2.5rem;
}

/* ===== Projects Grid ===== */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.5rem;
}

.project-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
  position: relative;
  overflow: hidden;
}

.project-card::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), #8b5cf6, #ec4899);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s ease;
}

.project-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.project-card p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 1.25rem;
  flex-grow: 1;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.25rem;
}

.tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  padding: 0.25rem 0.75rem;
  background: var(--tag-bg);
  color: var(--text-secondary);
  border-radius: 9999px;
}

.project-links {
  display: flex;
  gap: 0.75rem;
}

.project-links .btn {
  font-size: 0.8rem;
  padding: 0.5rem 1rem;
}

/* ===== Skills ===== */
.skills-group {
  margin-bottom: 2.5rem;
}

.skills-group:last-child {
  margin-bottom: 0;
}

.skills-group h3 {
  font-size: 1rem;
  font-weight: 600;
  text-align: center;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 1.25rem;
}

.skills-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
}

.skill-badge {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 500;
  padding: 0.6rem 1.25rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text-primary);
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

/* ===== Contact ===== */
#contact {
  background: var(--bg-secondary);
}

#contact-form {
  max-width: 540px;
  margin: 0 auto 2.5rem;
}

.form-group {
  margin-bottom: 1.25rem;
}

.form-group label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 0.4rem;
  color: var(--text-primary);
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 0.75rem 1rem;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  color: var(--text-primary);
  background: var(--bg-primary);
  border: 1px solid var(--border);
  border-radius: 8px;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
  outline: none;
}

.form-group textarea {
  resize: vertical;
  min-height: 120px;
}

#contact-form .btn-primary {
  width: 100%;
  padding: 0.85rem;
  font-size: 1rem;
}

.form-status {
  text-align: center;
  margin-top: 1rem;
  font-size: 0.9rem;
  min-height: 1.5rem;
}

.form-status.success { color: #16a34a; }
.form-status.error { color: #dc2626; }

.social-links {
  display: flex;
  justify-content: center;
  gap: 1.25rem;
}

.social-links a {
  color: var(--text-secondary);
  transition: color 0.2s ease, transform 0.2s ease;
}

.social-links a:hover {
  color: var(--accent);
  transform: translateY(-2px);
}

/* ===== Footer ===== */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 2rem 0;
  text-align: center;
}

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

.site-footer p {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.back-to-top {
  font-size: 0.85rem;
  font-weight: 500;
}

/* ===== Scroll Animations ===== */
.animate-on-scroll {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.animate-on-scroll.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Hero fade in */
.hero-content {
  opacity: 0;
  transform: translateY(20px);
}

.hero-content.loaded {
  opacity: 1;
  transform: translateY(0);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

/* ===== Hover Effects ===== */
@media (hover: hover) {
  .project-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 24px var(--shadow);
    border-color: var(--accent);
  }

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

  .skill-badge:hover {
    transform: translateY(-2px);
    border-color: var(--accent);
    box-shadow: 0 4px 12px var(--shadow);
  }
}

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

  html { scroll-behavior: auto; }

  .animate-on-scroll {
    opacity: 1;
    transform: none;
  }

  .hero-content {
    opacity: 1;
    transform: none;
  }

  .typing {
    width: auto;
    border-right: none;
    overflow: visible;
  }
}

/* ===== Mobile Responsive ===== */
@media (max-width: 768px) {
  .nav-toggle {
    display: block;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 4rem;
    left: 0;
    right: 0;
    background: var(--nav-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    flex-direction: column;
    padding: 1rem 1.5rem;
    gap: 0;
    border-bottom: 1px solid var(--border);
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links li {
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--border);
  }

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

  .typing {
    white-space: normal;
  }

  .container {
    padding: 0 2rem;
  }

  .hero {
    min-height: auto;
    padding: 5rem 2rem 3rem;
  }

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

  section {
    padding: 3.5rem 0;
  }

  .site-footer .container {
    flex-direction: column;
    gap: 0.75rem;
  }
}