/* ===========================
   Dai Tech Lab - Research Lab Aesthetic
   Minimal • Technical • Calm
   =========================== */

:root {
  /* Colors - Dark, understated palette */
  --bg-primary: #09090b;
  --bg-secondary: #0c0c0e;
  --bg-tertiary: #131316;
  --bg-elevated: #18181b;

  --text-primary: #fafafa;
  --text-secondary: #a1a1aa;
  --text-tertiary: #71717a;
  --text-muted: #52525b;

  --accent: #e4e4e7;
  --accent-dim: #3f3f46;

  --border: #27272a;
  --border-subtle: #1f1f23;

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

  /* Spacing scale */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;

  /* Layout */
  --container-max: 1120px;
  --container-narrow: 720px;

  /* Motion */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --duration-fast: 150ms;
  --duration-base: 300ms;
  --duration-slow: 500ms;
}

/* Light theme */
[data-theme="light"] {
  --bg-primary: #fafafa;
  --bg-secondary: #f4f4f5;
  --bg-tertiary: #e4e4e7;
  --bg-elevated: #ffffff;

  --text-primary: #09090b;
  --text-secondary: #3f3f46;
  --text-tertiary: #52525b;
  --text-muted: #71717a;

  --accent: #27272a;
  --accent-dim: #a1a1aa;

  --border: #d4d4d8;
  --border-subtle: #e4e4e7;
}

/* ===========================
   Reset
   =========================== */

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

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-primary);
}

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

ul, ol {
  list-style: none;
}

button {
  font: inherit;
  cursor: pointer;
  border: none;
  background: none;
  color: inherit;
}

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

/* ===========================
   Layout
   =========================== */

.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.section {
  padding: var(--space-24) 0;
}

/* ===========================
   Navigation
   =========================== */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: var(--space-4) 0;
  background: rgba(9, 9, 11, 0.8);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--duration-base) var(--ease-out), background var(--duration-base);
}

[data-theme="light"] .nav {
  background: rgba(250, 250, 250, 0.85);
}

.nav.scrolled {
  border-color: var(--border-subtle);
}

.nav-container {
  display: -webkit-flex;
  display: flex;
  -webkit-align-items: center;
  align-items: center;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.nav-container > * + * {
  margin-left: var(--space-6);
}

.nav-logo {
  display: -webkit-flex;
  display: flex;
  -webkit-align-items: center;
  align-items: center;
  font-weight: 500;
  font-size: 0.9375rem;
  letter-spacing: -0.01em;
}

.nav-logo > * + * {
  margin-left: var(--space-2);
}

.logo-symbol {
  color: var(--text-tertiary);
  font-size: 1.125rem;
}

.logo-text {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  letter-spacing: 0.05em;
}

.nav-links {
  display: -webkit-flex;
  display: flex;
  margin-left: auto;
}

.nav-links > li + li {
  margin-left: var(--space-8);
}

.nav-links a {
  font-size: 0.875rem;
  color: var(--text-tertiary);
  transition: color var(--duration-fast);
}

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

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 6px;
  padding: var(--space-2);
}

.nav-toggle span {
  width: 20px;
  height: 1.5px;
  background: var(--text-secondary);
  transition: var(--duration-fast);
}

/* Nav Controls */
.nav-controls {
  display: -webkit-flex;
  display: flex;
  -webkit-align-items: center;
  align-items: center;
  margin-left: auto;
}

.nav-controls > * + * {
  margin-left: var(--space-2);
}

.theme-toggle,
.lang-toggle {
  display: -webkit-flex;
  display: flex;
  -webkit-align-items: center;
  align-items: center;
  -webkit-justify-content: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  min-width: 36px;
  min-height: 36px;
  border-radius: 6px;
  color: var(--text-secondary);
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  cursor: pointer;
  -webkit-transition: all var(--duration-fast);
  transition: all var(--duration-fast);
  -webkit-appearance: none;
  appearance: none;
}

.theme-toggle:hover,
.lang-toggle:hover {
  color: var(--text-primary);
  background: var(--bg-tertiary);
  border-color: var(--border-subtle);
}

.theme-toggle .icon-sun,
.theme-toggle .icon-moon {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
}

.theme-toggle .icon-sun {
  display: none;
}

.theme-toggle .icon-moon {
  display: block;
}

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

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

.lang-toggle {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.05em;
}

.lang-current {
  font-size: inherit;
  font-weight: inherit;
  letter-spacing: inherit;
}

/* ===========================
   Hero Section
   =========================== */

.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-32) var(--space-6);
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.grid-pattern {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.02) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.02) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 40%, black, transparent);
  -webkit-mask-image: radial-gradient(ellipse 80% 60% at 50% 40%, black, transparent);
}

[data-theme="light"] .grid-pattern {
  background-image:
    linear-gradient(rgba(0, 0, 0, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0, 0, 0, 0.04) 1px, transparent 1px);
}

.gradient-orb {
  position: absolute;
  top: 20%;
  left: 50%;
  transform: translateX(-50%);
  width: 800px;
  height: 400px;
  background: radial-gradient(ellipse, rgba(100, 100, 120, 0.08), transparent 60%);
  filter: blur(60px);
  animation: pulse-slow 8s ease-in-out infinite;
}

[data-theme="light"] .gradient-orb {
  background: radial-gradient(ellipse, rgba(100, 100, 200, 0.1), transparent 60%);
}

@keyframes pulse-slow {
  0%, 100% { opacity: 0.5; }
  50% { opacity: 0.8; }
}

.hero-content {
  position: relative;
  max-width: 720px;
  text-align: center;
}

.hero-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: var(--space-6);
}

.hero-title {
  font-size: clamp(2.5rem, 8vw, 4rem);
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: var(--space-6);
  background: linear-gradient(180deg, var(--text-primary) 0%, var(--text-secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: clamp(1.125rem, 3vw, 1.375rem);
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: var(--space-4);
}

.hero-highlight {
  color: var(--text-primary);
}

.hero-description {
  font-size: 1rem;
  color: var(--text-tertiary);
  max-width: 540px;
  margin: 0 auto var(--space-10);
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: var(--space-4);
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  font-size: 0.875rem;
  font-weight: 500;
  border-radius: 6px;
  transition: all var(--duration-fast);
}

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

.btn-primary:hover {
  background: var(--text-secondary);
}

.btn-ghost {
  color: var(--text-secondary);
  border: 1px solid var(--border);
}

.btn-ghost:hover {
  color: var(--text-primary);
  border-color: var(--accent-dim);
  background: var(--bg-tertiary);
}

.hero-scroll {
  position: absolute;
  bottom: var(--space-8);
  left: 50%;
  -webkit-transform: translateX(-50%);
  transform: translateX(-50%);
  display: -webkit-flex;
  display: flex;
  -webkit-flex-direction: column;
  flex-direction: column;
  -webkit-align-items: center;
  align-items: center;
}

.hero-scroll > * + * {
  margin-top: var(--space-3);
}

.hero-scroll span {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.scroll-line {
  width: 1px;
  height: 48px;
  background: linear-gradient(180deg, var(--text-muted), transparent);
  animation: scroll-fade 2s ease-in-out infinite;
}

@keyframes scroll-fade {
  0%, 100% { opacity: 0.3; }
  50% { opacity: 1; }
}

/* ===========================
   Section Headers
   =========================== */

.section-header {
  margin-bottom: var(--space-12);
}

.section-label {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: var(--space-3);
}

.section-title {
  font-size: clamp(1.5rem, 4vw, 2rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}

.section-subtitle {
  font-size: 1rem;
  color: var(--text-tertiary);
  margin-top: var(--space-2);
}

/* ===========================
   What We Do / Capabilities
   =========================== */

.work {
  background: var(--bg-primary);
  border-top: 1px solid var(--border-subtle);
}

.capabilities {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.capability {
  display: grid;
  grid-template-columns: 64px 1fr;
  gap: var(--space-6);
  padding: var(--space-10) 0;
  border-bottom: 1px solid var(--border-subtle);
}

.capability:last-child {
  border-bottom: none;
}

.capability-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: 12px;
  color: var(--text-muted);
  transition: all var(--duration-base) var(--ease-out);
}

.capability:hover .capability-icon {
  color: var(--text-secondary);
  border-color: var(--border);
}

.capability-content {
  padding-top: var(--space-1);
}

.capability-title {
  font-size: 1.125rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  margin-bottom: var(--space-3);
}

.capability-description {
  font-size: 0.9375rem;
  color: var(--text-tertiary);
  line-height: 1.7;
  margin-bottom: var(--space-4);
  max-width: 520px;
}

.capability-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.capability-tags span {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  padding: 6px 10px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: 4px;
  color: var(--text-muted);
  transition: all var(--duration-fast);
}

.capability:hover .capability-tags span {
  border-color: var(--border);
}

/* ===========================
   Current Focus
   =========================== */

.focus {
  background: var(--bg-primary);
}

.focus-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-4);
}

.focus-card {
  padding: var(--space-6);
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  transition: all var(--duration-base) var(--ease-out);
}

.focus-card:hover {
  border-color: var(--border);
  background: var(--bg-tertiary);
}

.focus-icon {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-4);
  color: var(--text-muted);
}

.focus-card h3 {
  font-size: 0.9375rem;
  font-weight: 500;
  margin-bottom: var(--space-2);
}

.focus-card p {
  font-size: 0.875rem;
  color: var(--text-tertiary);
  line-height: 1.6;
}

/* ===========================
   Projects
   =========================== */

.projects {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-subtle);
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-4);
  margin-bottom: var(--space-8);
}

.project-card {
  display: -webkit-flex;
  display: flex;
  -webkit-flex-direction: column;
  flex-direction: column;
  padding: var(--space-6);
  background: var(--bg-primary);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  -webkit-transition: all var(--duration-base) var(--ease-out);
  transition: all var(--duration-base) var(--ease-out);
  cursor: pointer;
}

.project-card:hover {
  border-color: var(--border);
  transform: translateY(-2px);
}

.project-meta {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
}

.project-status {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: var(--space-1) var(--space-2);
  background: var(--bg-tertiary);
  border-radius: 3px;
  color: var(--text-muted);
}

.project-status.active {
  background: rgba(52, 211, 153, 0.1);
  color: #34d399;
}

.project-year {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--text-muted);
}

.project-title {
  font-size: 1rem;
  font-weight: 500;
  margin-bottom: var(--space-3);
}

.project-description {
  font-size: 0.875rem;
  color: var(--text-tertiary);
  line-height: 1.6;
  margin-bottom: var(--space-4);
}

.project-stack {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.project-stack span {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  padding: var(--space-1) var(--space-2);
  background: var(--bg-tertiary);
  border-radius: 3px;
  color: var(--text-muted);
}

.project-link {
  display: block;
  margin-top: var(--space-4);
  padding-top: var(--space-4);
  border-top: 1px solid var(--border-subtle);
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-muted);
  -webkit-transition: color 0.15s;
  transition: color 0.15s;
}

.project-card:hover .project-link {
  color: var(--text-primary);
}

a.project-card {
  display: block;
  text-decoration: none;
}

.projects-note {
  text-align: center;
}

.projects-note p {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-size: 0.875rem;
  color: var(--text-muted);
}

.note-icon {
  color: var(--text-tertiary);
}

/* ===========================
   Philosophy
   =========================== */

.philosophy {
  background: var(--bg-primary);
  border-top: 1px solid var(--border-subtle);
}

.manifesto {
  max-width: var(--container-narrow);
  margin: 0 auto var(--space-12);
}

.manifesto-item {
  padding: var(--space-6) 0;
  border-bottom: 1px solid var(--border-subtle);
}

.manifesto-item:last-child {
  border-bottom: none;
}

.manifesto-item p {
  font-size: clamp(1.25rem, 3vw, 1.5rem);
  font-weight: 400;
  letter-spacing: -0.01em;
  color: var(--text-secondary);
  line-height: 1.4;
}

.philosophy-note {
  max-width: 540px;
  margin: 0 auto;
  text-align: center;
}

.philosophy-note p {
  font-size: 0.9375rem;
  color: var(--text-tertiary);
  line-height: 1.7;
}

/* ===========================
   Founder
   =========================== */

.founder {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-subtle);
  padding: var(--space-16) 0;
}

.founder-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-12);
  align-items: center;
  max-width: 900px;
}

.founder-label {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: var(--space-2);
}

.founder-name {
  font-size: 1.5rem;
  font-weight: 500;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-4);
}

.founder-description {
  font-size: 0.9375rem;
  color: var(--text-tertiary);
  line-height: 1.7;
  margin-bottom: var(--space-6);
}

.founder-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 0.875rem;
  color: var(--text-secondary);
  transition: color var(--duration-fast);
}

.founder-link:hover {
  color: var(--text-primary);
}

.founder-link svg {
  transition: transform var(--duration-fast);
}

.founder-link:hover svg {
  transform: translate(2px, -2px);
}

.founder-visual {
  position: relative;
  height: 200px;
}

.founder-pattern {
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(circle at 2px 2px, var(--border) 1px, transparent 1px);
  background-size: 24px 24px;
  border-radius: 8px;
  opacity: 0.5;
}

/* ===========================
   Contact
   =========================== */

.contact {
  background: var(--bg-primary);
  border-top: 1px solid var(--border-subtle);
  text-align: center;
}

.contact-content {
  max-width: 480px;
  margin: 0 auto;
}

.contact-description {
  font-size: 1rem;
  color: var(--text-tertiary);
  margin-bottom: var(--space-6);
  line-height: 1.7;
}

.contact-email {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 1.125rem;
  color: var(--text-primary);
  padding: var(--space-4) var(--space-8);
  border: 1px solid var(--border);
  border-radius: 6px;
  transition: all var(--duration-fast);
}

.contact-email:hover {
  background: var(--bg-tertiary);
  border-color: var(--accent-dim);
}

/* ===========================
   Footer
   =========================== */

.footer {
  padding: var(--space-8) 0;
  border-top: 1px solid var(--border-subtle);
}

.footer-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-4);
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 0.875rem;
  color: var(--text-tertiary);
}

.footer-brand .logo-symbol {
  font-size: 1rem;
}

.footer-links {
  display: flex;
  gap: var(--space-6);
}

.footer-links a {
  font-size: 0.8125rem;
  color: var(--text-muted);
  transition: color var(--duration-fast);
}

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

.footer-copyright {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* ===========================
   Responsive
   =========================== */

@media (max-width: 900px) {
  .projects-grid {
    grid-template-columns: 1fr;
  }

  .founder-content {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .founder-visual {
    display: none;
  }
}

@media (max-width: 768px) {
  :root {
    --space-6: 1.25rem;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-subtle);
    padding: var(--space-4) var(--space-6);
    gap: 0;
  }

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

  .nav-links a {
    display: block;
    padding: var(--space-3) 0;
    border-bottom: 1px solid var(--border-subtle);
  }

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

  .nav-toggle {
    display: flex;
  }

  .nav-toggle.active span:first-child {
    transform: rotate(45deg) translate(4px, 4px);
  }

  .nav-toggle.active span:last-child {
    transform: rotate(-45deg) translate(4px, -4px);
  }

  .nav-controls {
    margin-left: auto;
    margin-right: var(--space-2);
  }

  .theme-toggle,
  .lang-toggle {
    width: 32px;
    height: 32px;
  }

  .hero {
    padding: var(--space-24) var(--space-6) var(--space-16);
    min-height: auto;
  }

  .hero-scroll {
    display: none;
  }

  .section {
    padding: var(--space-16) 0;
  }

  .capability {
    grid-template-columns: 1fr;
    gap: var(--space-4);
  }

  .capability-icon {
    width: 40px;
    height: 40px;
  }

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

  .footer-content {
    flex-direction: column;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .hero-actions {
    flex-direction: column;
    width: 100%;
  }

  .btn {
    width: 100%;
    justify-content: center;
  }
}

/* ===========================
   Animations
   =========================== */

@media (prefers-reduced-motion: no-preference) {
  .section {
    opacity: 0;
    transform: translateY(24px);
    animation: fade-up 0.6s var(--ease-out) forwards;
  }

  .section:nth-child(2) { animation-delay: 0.1s; }
  .section:nth-child(3) { animation-delay: 0.15s; }
  .section:nth-child(4) { animation-delay: 0.2s; }
  .section:nth-child(5) { animation-delay: 0.25s; }
  .section:nth-child(6) { animation-delay: 0.3s; }
  .section:nth-child(7) { animation-delay: 0.35s; }
}

@keyframes fade-up {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ===========================
   Selection & Scrollbar
   =========================== */

::selection {
  background: var(--accent-dim);
  color: var(--text-primary);
}

::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--accent-dim);
}

/* ===========================
   Focus States
   =========================== */

:focus-visible {
  outline: 2px solid var(--accent-dim);
  outline-offset: 2px;
}