/* ============================================================
   Andrew Xiao — Portfolio
   Warm, editorial, centered single-column layout.
   ============================================================ */

:root {
  --bg: #faf6f0;
  --surface: #ffffff;
  --ink: #1f1b16;
  --ink-soft: #5c554c;
  --line: #e7ded2;
  --accent: #c85a3a;
  --accent-soft: #f3e0d8;
  --shadow: 0 2px 12px rgba(31, 27, 22, 0.06);
  --shadow-lift: 0 8px 24px rgba(31, 27, 22, 0.10);
}

[data-theme="dark"] {
  --bg: #17140f;
  --surface: #201c16;
  --ink: #f0e9df;
  --ink-soft: #a99f91;
  --line: #322c23;
  --accent: #e0784f;
  --accent-soft: #3a2a22;
  --shadow: 0 2px 12px rgba(0, 0, 0, 0.35);
  --shadow-lift: 0 8px 24px rgba(0, 0, 0, 0.45);
}

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

html { scroll-behavior: smooth; }

body {
  font-family: "Inter", system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.65;
  transition: background 0.3s ease, color 0.3s ease;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 {
  font-family: "Space Grotesk", system-ui, sans-serif;
  line-height: 1.2;
  font-weight: 600;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }

em { font-style: normal; color: var(--accent); }

/* ============ Header / Nav ============ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.nav {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0.9rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.monogram {
  justify-self: start;
  font-family: "Space Grotesk", system-ui, sans-serif;
  font-weight: 700;
  font-size: 1.35rem;
  color: var(--ink);
  transition: color 0.2s ease;
}
.monogram:hover { color: var(--accent); text-decoration: none; }

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

.nav-links a {
  color: var(--ink-soft);
  font-size: 0.92rem;
  font-weight: 500;
  position: relative;
}
.nav-links a::after {
  content: "";
  position: absolute;
  left: 0; bottom: -4px;
  width: 100%;
  height: 2px;
  background: var(--accent);
  border-radius: 2px;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.25s ease;
}
.nav-links a:hover { color: var(--ink); text-decoration: none; }
.nav-links a:hover::after,
.nav-links a.active::after { transform: scaleX(1); }
.nav-links a.active { color: var(--ink); }

#theme-toggle {
  background: none;
  border: 1px solid var(--line);
  border-radius: 0.5rem;
  color: var(--ink-soft);
  width: 2.1rem;
  height: 2.1rem;
  display: grid;
  place-items: center;
  cursor: pointer;
  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; }

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

main {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

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

.hero {
  padding: 6rem 0 5rem;
  display: flex;
  align-items: center;
  gap: 4rem;
}

.hero-text {
  flex: 1;
  min-width: 0;
}

.hero-photo {
  flex-shrink: 0;
}

.photo-placeholder {
  width: 260px;
  height: 300px;
  border-radius: 1.5rem;
  background: var(--line);
  border: 1px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--ink-soft);
  font-size: 0.9rem;
  font-weight: 500;
  overflow: hidden;
}

.photo-placeholder img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.hero-kicker {
  color: var(--accent);
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}

.hero-name {
  font-size: clamp(2.4rem, 6vw, 3.8rem);
  font-weight: 700;
  letter-spacing: -0.02em;
}

.hero-tagline {
  margin-top: 1.25rem;
  max-width: 34rem;
  font-size: 1.05rem;
  color: var(--ink-soft);
}

.hero-actions {
  margin-top: 2rem;
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.hero-socials {
  margin-top: 1.75rem;
  display: flex;
  gap: 1.5rem;
}

.hero-socials a {
  color: var(--ink-soft);
  display: grid;
  place-items: center;
  transition: color 0.2s ease, transform 0.2s ease;
}
.hero-socials a:hover {
  color: var(--accent);
  transform: translateY(-2px);
}

/* ============ Buttons ============ */

.btn {
  display: inline-block;
  padding: 0.65rem 1.4rem;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.2s ease;
}
.btn:hover { text-decoration: none; transform: translateY(-2px); }

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

.btn-ghost {
  border: 1.5px solid var(--line);
  color: var(--ink);
}
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); }

/* ============ Sections ============ */

.section { padding: 3.5rem 0; }

.section-title {
  font-size: 1.9rem;
  margin-bottom: 2rem;
  text-align: center;
}

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

.projects-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}

.project {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 1rem;
  padding: 1.4rem 1.5rem;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}
.project:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lift);
  border-color: var(--accent);
}

.project-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 0.4rem;
}

.project h3 {
  font-family: "Inter", system-ui, sans-serif;
  font-size: 1.05rem;
  font-weight: 600;
}

.project-icons {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.project-repo {
  color: var(--ink-soft);
  display: grid;
  place-items: center;
  transition: color 0.2s ease, transform 0.2s ease;
}
.project-repo:hover {
  color: var(--accent);
  transform: translateY(-2px);
}

.project p {
  color: var(--ink-soft);
  font-size: 0.9rem;
  flex-grow: 1;
}

/* ============ Tags ============ */

.tags {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 1rem;
}

.tags li {
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 600;
  padding: 0.25rem 0.7rem;
  border-radius: 999px;
  letter-spacing: 0.02em;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
  cursor: default;
}
.tags li:hover {
  transform: translateY(-3px) scale(1.06);
  background: var(--accent);
  color: #fff;
  box-shadow: 0 4px 12px rgba(200, 90, 58, 0.35);
}

/* ============ Skills ============ */

.skills-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}

.skill-group {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 1rem;
  padding: 1.25rem 1.4rem;
  box-shadow: var(--shadow);
}

.skill-group h3 {
  font-size: 1.05rem;
  margin-bottom: 0.35rem;
}

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

.contact-card {
  text-align: center;
}

.btn-icon {
  display: inline-grid;
  place-items: center;
  width: 4rem;
  height: 4rem;
  padding: 0;
  border-radius: 50%;
}

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

.site-footer {
  border-top: 1px solid var(--line);
  margin-top: 3rem;
  padding: 2rem 1.25rem;
  text-align: center;
  font-size: 0.88rem;
  color: var(--ink-soft);
}

/* ============ Scroll reveal ============ */

.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
}

/* ============ Mobile ============ */

@media (max-width: 640px) {
  .hero {
    flex-direction: column-reverse;
    align-items: center;
    text-align: center;
    padding: 3rem 0 3rem;
    gap: 2rem;
  }
  .hero-text { display: flex; flex-direction: column; align-items: center; }
  .hero-tagline { font-size: 1rem; }
  .hero-actions { justify-content: center; }
  .hero-socials { justify-content: center; }
  .photo-placeholder { width: 160px; height: 180px; }

  .nav-links { gap: 1rem; }
  .nav-links a { font-size: 0.85rem; }

  .section { padding: 2.5rem 0; }
  .section-title { font-size: 1.6rem; }

  .projects-grid { grid-template-columns: 1fr; }
  .project { padding: 1.25rem 1.25rem; }

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