/* ===== CSS Variables ===== */
:root {
  /* Light theme (default) */
  --bg: #fafafa;
  --bg-soft: #f1f1f3;
  --bg-card: #ffffff;
  --text-primary: #1a1a1a;
  --text-secondary: #5f5f66;
  --accent: #4a5cff;
  --accent-soft: rgba(74, 92, 255, 0.12);
  --accent-glow: rgba(74, 92, 255, 0.18);
  --border: #e6e6e6;
  --border-strong: #d5d5d5;
  --dot: rgba(0, 0, 0, 0.05);
  --header-bg: rgba(255, 255, 255, 0.72);
  --shadow-md: 0 8px 30px rgba(0, 0, 0, 0.08);

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto,
    Helvetica, Arial, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', ui-monospace, monospace;

  --transition: 0.2s ease;
}

:root[data-theme="dark"] {
  --bg: #0e0e10;
  --bg-soft: #17171b;
  --bg-card: #161619;
  --text-primary: #f2f2f4;
  --text-secondary: #9a9aa4;
  --accent: #7d8cff;
  --accent-soft: rgba(125, 140, 255, 0.16);
  --accent-glow: rgba(125, 140, 255, 0.32);
  --border: #26262b;
  --border-strong: #35353c;
  --dot: rgba(255, 255, 255, 0.05);
  --header-bg: rgba(16, 16, 19, 0.72);
  --shadow-md: 0 10px 34px rgba(0, 0, 0, 0.5);
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  position: relative;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  transition: background-color var(--transition), color var(--transition);
}

/* Subtle dot grid + soft accent glow background */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image:
    radial-gradient(circle at 15% 15%, var(--accent-soft) 0%, transparent 40%),
    radial-gradient(circle at 85% 85%, var(--accent-soft) 0%, transparent 40%),
    radial-gradient(var(--dot) 1px, transparent 1px);
  background-size: 100% 100%, 100% 100%, 22px 22px;
  pointer-events: none;
  z-index: 0;
}

main {
  position: relative;
  z-index: 1;
}

/* ===== Header ===== */
.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.9rem 3rem;
  border-bottom: 1px solid var(--border);
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: var(--header-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  z-index: 100;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.2em;
  line-height: 1;
  transition: opacity var(--transition);
}

.logo:hover {
  opacity: 0.7;
}

.logo-icon {
  font-size: 0.7rem;
  color: var(--accent);
  line-height: 1;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.nav {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav a {
  color: var(--text-secondary);
  text-decoration: none;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  transition: color var(--transition);
}

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

/* ===== Theme Toggle ===== */
.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  padding: 0;
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  transition: color var(--transition), border-color var(--transition), transform var(--transition);
}

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

.theme-toggle svg {
  width: 16px;
  height: 16px;
}

/* Show the moon in light mode, the sun in dark mode */
.theme-toggle .icon-sun {
  display: none;
}

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

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

/* ===== Sections Base ===== */
.section {
  min-height: auto;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 5rem 4rem;
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.8s ease, transform 0.8s ease;
}

.section + .section {
  padding-top: 4rem;
}

.intro-section + .section {
  padding-top: 4rem;
}

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

/* ===== Section Divider ===== */
.section-divider {
  width: 100%;
  max-width: 480px;
  height: 1px;
  margin: 2rem auto;
  background: linear-gradient(
    90deg,
    transparent 0%,
    var(--accent-soft) 20%,
    var(--accent) 50%,
    var(--accent-soft) 80%,
    transparent 100%
  );
  opacity: 0.6;
}

/* ===== Intro Section ===== */
.intro-section {
  text-align: center;
  min-height: 100vh;
  justify-content: center;
  padding-top: 4rem;
}

.tagline {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.25em;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
}

.main-title {
  font-size: clamp(3rem, 10vw, 6rem);
  font-weight: 800;
  line-height: 1.05;
  letter-spacing: -0.03em;
  margin-bottom: 1.5rem;
}

.description {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 620px;
  margin: 0 auto 2rem;
  line-height: 1.75;
}

/* ===== Logo Conveyor Belt ===== */
.logo-conveyor-wrap {
  width: 100%;
  max-width: 620px;
  margin: 0 auto 2.5rem;
  padding: 1.25rem 0;
  overflow: hidden;
  -webkit-mask-image: linear-gradient(90deg, transparent 0%, black 8%, black 92%, transparent 100%);
  mask-image: linear-gradient(90deg, transparent 0%, black 8%, black 92%, transparent 100%);
}

.logo-conveyor {
  width: 100%;
  overflow: hidden;
}

.logo-conveyor-track {
  display: flex;
  gap: 2.25rem;
  width: max-content;
  animation: conveyor-scroll 40s linear infinite;
}

.logo-conveyor-track:hover {
  animation-play-state: paused;
}

.logo-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.logo-icon-wrap {
  min-height: 56px;
  display: grid;
  place-items: center;
}

.logo-icon {
  height: 56px;
  width: auto;
  opacity: 0.9;
  transition: opacity var(--transition);
}

.logo-item:hover .logo-icon {
  opacity: 1;
}

.logo-fallback {
  display: none;
  font-size: 1.05rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--text-secondary);
  text-transform: uppercase;
}

.logo-label {
  margin-top: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  color: var(--text-secondary);
}

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

.logo-item.no-logo .logo-icon {
  display: none;
}

.logo-item.no-logo .logo-fallback {
  display: inline-block;
}

@keyframes conveyor-scroll {
  0% {
    transform: translateX(0);
  }
  100% {
    transform: translateX(-50%);
  }
}

.intro-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.9rem 1.75rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  text-decoration: none;
  border-radius: 8px;
  cursor: pointer;
  transition: all var(--transition);
}

.btn-icon {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
}

.btn-primary {
  color: #fff;
  border: 1px solid var(--accent);
  background: var(--accent);
  box-shadow: 0 8px 24px var(--accent-glow);
}

.btn-primary:hover {
  filter: brightness(1.05);
  box-shadow: 0 10px 30px var(--accent-glow);
  transform: translateY(-2px);
}

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

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

/* ===== Section Titles ===== */
.section-title {
  font-family: var(--font-sans);
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 2rem;
}

.projects-section .section-title {
  font-size: clamp(2rem, 5vw, 3rem);
}

/* ===== About Section ===== */
.about-section {
  align-items: center;
  text-align: center;
  max-width: 760px;
  margin: 0 auto;
}

.about-text {
  font-size: 1.1rem;
  color: var(--text-secondary);
  line-height: 1.85;
}

/* ===== Projects Section ===== */
.projects-section {
  align-items: center;
  text-align: center;
}

.projects-section .section-title {
  text-align: center;
}

.projects-intro {
  color: var(--text-secondary);
  max-width: 640px;
  margin: 0 auto 3rem;
  text-align: center;
  line-height: 1.75;
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.9rem;
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 1rem;
}

/* ===== Project Tile ===== */
.project-tile {
  display: flex;
  flex-direction: column;
  text-decoration: none;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

.project-tile:hover {
  border-color: var(--accent);
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.project-thumb-wrap {
  width: 100%;
  aspect-ratio: 4 / 3;
  overflow: hidden;
  background: var(--bg-soft);
}

.project-thumbnail {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  transition: transform var(--transition);
}

.project-tile:hover .project-thumbnail {
  transform: scale(1.04);
}

.project-info {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 1.15rem 1.3rem 1.35rem;
  text-align: left;
}

.project-name {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
}

.project-category {
  font-family: var(--font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-secondary);
  margin-top: 0.4rem;
}

.project-arrow {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  color: var(--text-secondary);
  transition: color var(--transition), transform var(--transition);
}

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

.project-arrow svg {
  width: 100%;
  height: 100%;
  stroke: currentColor;
}

/* ===== Responsive ===== */
@media (max-width: 1000px) {
  .projects-grid {
    grid-template-columns: repeat(2, 1fr);
    max-width: 800px;
  }
}

@media (max-width: 768px) {
  .header {
    padding: 1rem 1.5rem;
  }

  .nav {
    gap: 1rem;
  }

  .nav a {
    font-size: 0.65rem;
  }

  .intro-buttons {
    flex-direction: column;
  }

  .section {
    padding: 4rem 1.5rem;
  }

  .section + .section {
    padding-top: 3rem;
  }
}

@media (max-width: 560px) {
  .projects-grid {
    grid-template-columns: 1fr;
    padding: 0;
  }
}