:root {
  --bg: #ffffff;
  --bg-secondary: #f5f5f7;
  --bg-card: #ffffff;
  --text: #1d1d1f;
  --text-secondary: #6e6e73;
  --text-tertiary: #aeaeb2;
  --border: rgba(0,0,0,0.08);
  --accent: #0071e3;
  --accent-hover: #0077ed;
  --tag-bg: #f5f5f7;
  --tag-text: #1d1d1f;
  --nav-bg: rgba(255,255,255,0.72);
  --shadow: 0 2px 20px rgba(0,0,0,0.06);
  --shadow-hover: 0 8px 40px rgba(0,0,0,0.12);
}

[data-theme="dark"] {
  --bg: #000000;
  --bg-secondary: #1c1c1e;
  --bg-card: #1c1c1e;
  --text: #f5f5f7;
  --text-secondary: #aeaeb2;
  --text-tertiary: #6e6e73;
  --border: rgba(255,255,255,0.08);
  --accent: #2997ff;
  --accent-hover: #409cff;
  --tag-bg: #2c2c2e;
  --tag-text: #f5f5f7;
  --nav-bg: rgba(0,0,0,0.72);
  --shadow: 0 2px 20px rgba(0,0,0,0.3);
  --shadow-hover: 0 8px 40px rgba(0,0,0,0.5);
}

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

html { scroll-behavior: smooth; }

body {
  font-family: 'DM Sans', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  transition: background 0.3s, color 0.3s;
  -webkit-font-smoothing: antialiased;
}

/* NAV */
nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: var(--nav-bg);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--border);
  transition: background 0.3s;
}

.nav-inner {
  max-width: 980px;
  margin: 0 auto;
  padding: 0 24px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-size: 17px;
  font-weight: 500;
  color: var(--text);
  text-decoration: none;
  letter-spacing: -0.3px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}

.nav-links a {
  font-size: 13px;
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.2s;
  letter-spacing: 0.1px;
}

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

.lang-toggle, .theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-secondary);
  font-size: 13px;
  font-family: 'DM Sans', sans-serif;
  padding: 4px 8px;
  border-radius: 6px;
  transition: color 0.2s, background 0.2s;
  letter-spacing: 0.1px;
}

.lang-toggle:hover, .theme-toggle:hover {
  color: var(--text);
  background: var(--tag-bg);
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 8px;
}

.theme-toggle {
  font-size: 16px;
  padding: 4px 6px;
}

/* MAIN */
main { padding-top: 52px; }

section {
  max-width: 980px;
  margin: 0 auto;
  padding: 0 24px;
}

/* HERO */
.hero {
  padding-top: 120px;
  padding-bottom: 100px;
  max-width: 980px;
  margin: 0 auto;
  padding-left: 24px;
  padding-right: 24px;
}

.hero-eyebrow {
  font-family: 'DM Mono', monospace;
  font-size: 12px;
  font-weight: 300;
  color: var(--accent);
  letter-spacing: 1.5px;
  text-transform: uppercase;
  margin-bottom: 24px;
  opacity: 0;
  animation: fadeUp 0.8s ease 0.1s forwards;
}

.hero h1 {
  font-size: clamp(48px, 7vw, 80px);
  font-weight: 300;
  letter-spacing: -2px;
  line-height: 1.05;
  color: var(--text);
  margin-bottom: 28px;
  opacity: 0;
  animation: fadeUp 0.8s ease 0.2s forwards;
}

.hero h1 em {
  font-style: normal;
  color: var(--text-secondary);
}

.hero-sub {
  font-size: 19px;
  font-weight: 300;
  color: var(--text-secondary);
  max-width: 560px;
  line-height: 1.6;
  margin-bottom: 48px;
  opacity: 0;
  animation: fadeUp 0.8s ease 0.3s forwards;
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  opacity: 0;
  animation: fadeUp 0.8s ease 0.4s forwards;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--accent);
  color: white;
  padding: 12px 24px;
  border-radius: 980px;
  font-size: 15px;
  font-weight: 400;
  text-decoration: none;
  transition: background 0.2s, transform 0.2s;
  letter-spacing: -0.1px;
}

.btn-primary:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: transparent;
  color: var(--accent);
  padding: 12px 24px;
  border-radius: 980px;
  border: 1px solid var(--border);
  font-size: 15px;
  font-weight: 400;
  text-decoration: none;
  transition: background 0.2s, transform 0.2s;
  letter-spacing: -0.1px;
}

.btn-secondary:hover {
  background: var(--tag-bg);
  transform: translateY(-1px);
}

/* DIVIDER */
.divider {
  max-width: 980px;
  margin: 0 auto;
  padding: 0 24px;
  border: none;
  border-top: 1px solid var(--border);
}

/* SECTION TITLE */
.section-label {
  font-family: 'DM Mono', monospace;
  font-size: 11px;
  font-weight: 300;
  color: var(--text-tertiary);
  letter-spacing: 2px;
  text-transform: uppercase;
  margin-bottom: 48px;
}

/* ABOUT */
.about {
  padding: 100px 24px;
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: start;
}

.about-text h2 {
  font-size: clamp(32px, 4vw, 48px);
  font-weight: 300;
  letter-spacing: -1.5px;
  line-height: 1.1;
  margin-bottom: 28px;
  color: var(--text);
}

.about-text p {
  font-size: 17px;
  font-weight: 300;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 16px;
}

.stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2px;
  margin-top: 8px;
}

.stat {
  background: var(--bg-secondary);
  padding: 28px 24px;
  border-radius: 0;
  transition: background 0.3s;
}

.stat:first-child { border-radius: 16px 0 0 0; }
.stat:nth-child(2) { border-radius: 0 16px 0 0; }
.stat:nth-child(3) { border-radius: 0 0 0 16px; }
.stat:last-child { border-radius: 0 0 16px 0; }

.stat-number {
  font-size: 36px;
  font-weight: 300;
  letter-spacing: -1px;
  color: var(--text);
  margin-bottom: 4px;
}

.stat-label {
  font-size: 13px;
  color: var(--text-secondary);
}

/* SERVICES */
.services {
  padding: 100px 24px;
  background: var(--bg-secondary);
  max-width: 100%;
  transition: background 0.3s;
}

.services-inner {
  max-width: 980px;
  margin: 0 auto;
}

.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2px;
}

.service-card {
  background: var(--bg-card);
  padding: 40px 32px;
  border-radius: 0;
  transition: background 0.3s, transform 0.3s, box-shadow 0.3s;
  cursor: default;
}

.service-card:first-child { border-radius: 20px 0 0 20px; }
.service-card:last-child { border-radius: 0 20px 20px 0; }

.service-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
  z-index: 1;
  position: relative;
  border-radius: 20px;
}

.service-icon {
  font-size: 32px;
  margin-bottom: 24px;
  display: block;
}

.service-card h3 {
  font-size: 20px;
  font-weight: 400;
  letter-spacing: -0.5px;
  margin-bottom: 12px;
  color: var(--text);
}

.service-card p {
  font-size: 15px;
  font-weight: 300;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* SKILLS */
.skills {
  padding: 100px 24px;
}

.skills-layout {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 80px;
}

.skills-nav {
  list-style: none;
  position: sticky;
  top: 80px;
}

.skills-nav li {
  margin-bottom: 4px;
}

.skills-nav button {
  background: none;
  border: none;
  cursor: pointer;
  font-family: 'DM Sans', sans-serif;
  font-size: 15px;
  font-weight: 300;
  color: var(--text-secondary);
  padding: 8px 12px;
  border-radius: 8px;
  text-align: left;
  width: 100%;
  transition: color 0.2s, background 0.2s;
}

.skills-nav button:hover,
.skills-nav button.active {
  color: var(--text);
  background: var(--tag-bg);
}

.skills-nav button.active {
  font-weight: 400;
}

.skill-category { display: none; }
.skill-category.active { display: block; }

.skill-category h3 {
  font-size: 28px;
  font-weight: 300;
  letter-spacing: -0.8px;
  margin-bottom: 32px;
  color: var(--text);
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.skill-tag {
  display: inline-flex;
  align-items: center;
  background: var(--tag-bg);
  color: var(--tag-text);
  padding: 8px 16px;
  border-radius: 980px;
  font-size: 14px;
  font-weight: 300;
  transition: background 0.2s;
  border: 1px solid var(--border);
}

.skill-tag:hover {
  background: var(--border);
}

/* STACK */
.stack-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
  gap: 12px;
  margin-top: 16px;
}

.stack-item {
  background: var(--bg-secondary);
  border-radius: 12px;
  padding: 20px 16px;
  text-align: center;
  transition: background 0.2s, transform 0.2s;
}

.stack-item:hover {
  background: var(--tag-bg);
  transform: translateY(-2px);
}

.stack-item .icon { font-size: 24px; margin-bottom: 8px; display: block; }
.stack-item .name { font-size: 13px; font-weight: 300; color: var(--text-secondary); }

/* PROJECTS */
.projects {
  padding: 100px 24px;
  background: var(--bg-secondary);
  max-width: 100%;
  transition: background 0.3s;
}

.projects-inner {
  max-width: 980px;
  margin: 0 auto;
}

.projects-header {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  margin-bottom: 48px;
}

.projects-title h2 {
  font-size: clamp(32px, 4vw, 48px);
  font-weight: 300;
  letter-spacing: -1.5px;
  color: var(--text);
}

.projects-note {
  font-size: 14px;
  font-weight: 300;
  color: var(--text-tertiary);
  font-style: italic;
  padding-bottom: 8px;
}

.project-list {
  display: grid;
  gap: 2px;
}

.project-card {
  background: var(--bg-card);
  padding: 32px;
  border-radius: 0;
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 24px;
  transition: background 0.3s, transform 0.2s;
  cursor: default;
}

.project-card:first-child { border-radius: 20px 20px 0 0; }
.project-card:last-child { border-radius: 0 0 20px 20px; }

.project-card:hover {
  transform: translateX(4px);
}

.project-card h3 {
  font-size: 18px;
  font-weight: 400;
  letter-spacing: -0.3px;
  color: var(--text);
  margin-bottom: 6px;
}

.project-card p {
  font-size: 14px;
  font-weight: 300;
  color: var(--text-secondary);
  line-height: 1.5;
}

.project-tags {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin-top: 12px;
}

.project-tag {
  font-size: 12px;
  font-weight: 300;
  color: var(--accent);
  background: transparent;
  border: 1px solid var(--border);
  padding: 3px 10px;
  border-radius: 980px;
}

.project-arrow {
  font-size: 20px;
  color: var(--text-tertiary);
  transition: color 0.2s, transform 0.2s;
}

.project-card:hover .project-arrow {
  color: var(--accent);
  transform: translateX(4px);
}

/* CONTACT */
.contact {
  padding: 120px 24px;
  text-align: center;
}

.contact h2 {
  font-size: clamp(36px, 5vw, 64px);
  font-weight: 300;
  letter-spacing: -2px;
  line-height: 1.05;
  margin-bottom: 20px;
  color: var(--text);
}

.contact p {
  font-size: 19px;
  font-weight: 300;
  color: var(--text-secondary);
  margin-bottom: 48px;
}

.contact-links {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

/* FOOTER */
footer {
  border-top: 1px solid var(--border);
  padding: 28px 24px;
  text-align: center;
}

footer p {
  font-size: 13px;
  font-weight: 300;
  color: var(--text-tertiary);
}

/* ANIMATIONS */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.fade-in {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

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

/* RESPONSIVE */
@media (max-width: 768px) {
  .about-grid { grid-template-columns: 1fr; gap: 48px; }
  .services-grid { grid-template-columns: 1fr; }
  .service-card:first-child { border-radius: 20px 20px 0 0; }
  .service-card:last-child { border-radius: 0 0 20px 20px; }
  .skills-layout { grid-template-columns: 1fr; gap: 32px; }
  .skills-nav { position: static; display: flex; flex-wrap: wrap; gap: 8px; }
  .skills-nav li { margin: 0; }
  .skills-nav button { padding: 6px 12px; white-space: nowrap; }
  .projects-header { flex-direction: column; align-items: flex-start; gap: 8px; }
  .nav-links { display: none; }
  .hero h1 { font-size: 40px; }
}