:root {
  --bg: #080a0d;
  --bg-elevated: #11161b;
  --bg-card: #171d23;
  --text: #edf2f5;
  --text-muted: #aab4bd;
  --accent: #8f82ed;
  --accent-light: #b9b0ff;
  --accent-strong: #6258c8;
  --accent-rgb: 143, 130, 237;
  --accent-light-rgb: 185, 176, 255;
  --border: rgba(237,242,245,0.12);
  --nav-bg: rgba(8,10,13,0.92);
  --particle-rgb: 190, 211, 224;
  --button-bg: #20272e;
  --button-text: #f5f7f8;
  --button-shadow: rgba(0,0,0,0.35);
  --theme-icon-color: #e6edf2;
  --radius: 14px;
}

:root[data-theme="light"] {
  --bg: #f5f1e6;
  --bg-elevated: #ebe3cd;
  --bg-card: #fffaf0;
  --text: #332d24;
  --text-muted: #706858;
  --accent: #a2762f;
  --accent-light: #856126;
  --accent-strong: #6f501f;
  --accent-rgb: 162, 118, 47;
  --accent-light-rgb: 133, 97, 38;
  --border: rgba(71,57,35,0.18);
  --nav-bg: rgba(245,241,230,0.93);
  --particle-rgb: 170, 132, 58;
  --button-bg: #d8bd73;
  --button-text: #332817;
  --button-shadow: rgba(101,78,32,0.22);
  --theme-icon-color: #a2762f;
}

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

html {
  scroll-behavior: smooth;
  background: var(--bg);
  transition: background-color 0.45s ease;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  overflow-x: hidden;
  transition: opacity 0.45s cubic-bezier(0.22, 1, 0.36, 1),
              background-color 0.35s ease, color 0.35s ease;
}

/* ===== Page transition ===== */
body.page-fading {
  opacity: 0;
  pointer-events: none;
}

/* 子页面先由主题色遮罩覆盖，再柔和地显现内容。 */
body.subpage::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 9998;
  background: var(--bg);
  opacity: 1;
  pointer-events: none;
  transition: opacity 0.6s cubic-bezier(0.22, 1, 0.36, 1);
  will-change: opacity;
}
body.subpage.page-enter::before {
  opacity: 0;
}

@media (prefers-reduced-motion: reduce) {
  body {
    transition: none;
  }
  body.subpage::before {
    transition: none;
  }
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

/* ===== Navigation ===== */
.nav {
  position: fixed;
  top: 0; left: 0;
  width: 100%;
  z-index: 1000;
  padding: 20px 5vw;
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: background 0.3s ease, backdrop-filter 0.3s ease;
}
.nav.scrolled {
  background: var(--nav-bg);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}
.nav-logo {
  width: 34px;
  height: 34px;
  object-fit: contain;
  flex: 0 0 34px;
}
.logo span { color: var(--accent-light); }
.theme-toggle {
  width: 42px;
  height: 42px;
  margin-left: auto;
  margin-right: 14px;
  border: 1px solid var(--border);
  border-radius: 50%;
  background: var(--bg-card);
  color: var(--theme-icon-color);
  display: inline-grid;
  place-items: center;
  font-size: 1.25rem;
  line-height: 1;
  cursor: pointer;
  transition: color 0.25s ease, background 0.25s ease, border-color 0.25s ease, transform 0.2s ease;
}
.theme-toggle:hover { color: var(--accent-light); transform: translateY(-1px); }
.theme-toggle:focus-visible { outline: 2px solid var(--accent-light); outline-offset: 3px; }
.theme-icon-light { display: none; }
:root[data-theme="light"] .theme-icon-dark { display: none; }
:root[data-theme="light"] .theme-icon-light { display: inline; }

/* ===== Hero ===== */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  padding: 120px 5vw 80px;
  position: relative;
}
.hero-content { position: relative; z-index: 1; max-width: 900px; }
.hero-label {
  display: inline-block;
  padding: 8px 18px;
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 2rem;
  background: var(--bg-card);
}
.hero-title {
  font-size: clamp(2.6rem, 7vw, 5.5rem);
  font-weight: 800;
  line-height: 1.05;
  letter-spacing: -0.03em;
  margin-bottom: 1.5rem;
}
.gradient-text {
  background: linear-gradient(135deg, var(--text) 0%, var(--accent-light) 50%, var(--accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--text-muted);
  max-width: 640px;
  margin: 0 auto 2.5rem;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  border-radius: 999px;
  font-size: 1rem;
  font-weight: 600;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  cursor: pointer;
  border: none;
}
.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-strong));
  color: var(--button-text);
  box-shadow: 0 10px 30px rgba(var(--accent-rgb),0.3);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 14px 40px rgba(var(--accent-rgb),0.4);
}
.btn-outline {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
  margin-left: 1rem;
}
.btn-outline:hover { border-color: var(--accent-light); color: var(--accent-light); }

/* ===== Sections ===== */
.section { padding: 100px 5vw; max-width: 1200px; margin: 0 auto; }
.section-title {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 1rem;
}
.section-desc {
  color: var(--text-muted);
  max-width: 560px;
  margin-bottom: 3rem;
  font-size: 1.05rem;
}

/* ===== About ===== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
}
.about-text p { color: var(--text-muted); margin-bottom: 1.2rem; }
.about-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  margin-top: 2.5rem;
}
.stat-item {
  padding: 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.stat-number { font-size: 2rem; font-weight: 800; color: var(--text); }
.stat-label { font-size: 0.85rem; color: var(--text-muted); }
.about-image {
  position: relative;
  border-radius: var(--radius);
  overflow: hidden;
  aspect-ratio: 4/3;
}
.about-image img {
  width: 100%; height: 100%;
  object-fit: cover;
  transition: transform 0.6s ease;
}
.about-image:hover img { transform: scale(1.05); }

/* ===== Services ===== */
.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}
.service-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  transition: transform 0.3s ease, border-color 0.3s ease;
}
.service-card:hover { transform: translateY(-6px); border-color: rgba(var(--accent-rgb),0.4); }
.service-icon {
  width: 48px; height: 48px;
  border-radius: 12px;
  background: rgba(var(--accent-rgb),0.15);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 1.2rem;
}
.service-title { font-size: 1.15rem; font-weight: 700; margin-bottom: 0.6rem; }
.service-desc { color: var(--text-muted); font-size: 0.95rem; line-height: 1.6; }

/* ===== Portfolio ===== */
.portfolio-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}
.portfolio-item {
  position: relative;
  border-radius: var(--radius);
  overflow: hidden;
  aspect-ratio: 16/10;
  cursor: pointer;
}
.portfolio-item img {
  width: 100%; height: 100%;
  object-fit: cover;
  transition: transform 0.6s ease;
}
.portfolio-item:hover img { transform: scale(1.08); }
.portfolio-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, rgba(0,0,0,0.85) 0%, transparent 60%);
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  padding: 1.8rem;
  opacity: 0;
  transition: opacity 0.3s ease;
}
.portfolio-item:hover .portfolio-overlay { opacity: 1; }
.portfolio-tag { font-size: 0.8rem; color: var(--accent-light); margin-bottom: 0.4rem; }
.portfolio-title { font-size: 1.25rem; font-weight: 700; }

/* ===== CTA ===== */
.cta {
  text-align: center;
  background: var(--bg-elevated);
  border-radius: 24px;
  padding: 80px 5vw;
  margin: 0 auto 100px;
  max-width: 1200px;
  position: relative;
  overflow: hidden;
}
.cta::before {
  content: "";
  position: absolute;
  top: -50%; left: -20%;
  width: 140%; height: 200%;
  background: radial-gradient(circle at center, rgba(var(--accent-rgb),0.12), transparent 50%);
  pointer-events: none;
}
.cta-content { position: relative; z-index: 1; }
.cta-title { font-size: clamp(2rem, 4vw, 3rem); font-weight: 700; margin-bottom: 1rem; }
.cta-desc { color: var(--text-muted); max-width: 560px; margin: 0 auto 2rem; }

/* ===== Footer ===== */
.footer {
  border-top: 1px solid var(--border);
  padding: 40px 5vw;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--text-muted);
  font-size: 0.9rem;
  max-width: 1200px;
  margin: 0 auto;
  flex-wrap: wrap;
  gap: 1rem;
}
.footer-links { display: flex; gap: 1.5rem; }
.footer-links a:hover { color: var(--text); }

/* ===== Scroll reveal ===== */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.8s ease, transform 0.8s ease;
}
.reveal.active { opacity: 1; transform: translateY(0); }

/* ===== Intro overlay ===== */
.intro {
  position: fixed;
  inset: 0;
  background: var(--bg);
  z-index: 9999;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  transition: opacity 0.9s cubic-bezier(0.22, 1, 0.36, 1),
              visibility 0.9s cubic-bezier(0.22, 1, 0.36, 1);
}
.intro.hidden { opacity: 0; visibility: hidden; pointer-events: none; }
.intro.skip { display: none; }   /* 本次会话已看过，直接跳过 */

.intro-logo {
  width: 520px; height: 520px;
  object-fit: contain;
  opacity: 0;
  transform: scale(0) rotate(-12deg);
  animation: introLogo 2.2s cubic-bezier(0.22, 1, 0.36, 1) forwards;
}
@keyframes introLogo {
  0%   { opacity: 0; transform: scale(0) rotate(-12deg); filter: drop-shadow(0 0 0 transparent); }
  40%  { opacity: 1; transform: scale(1.12) rotate(4deg); filter: drop-shadow(0 0 30px rgba(var(--accent-rgb),0.6)); }
  60%  { transform: scale(0.94) rotate(-2deg); filter: drop-shadow(0 0 45px rgba(var(--accent-light-rgb),0.7)); }
  80%  { transform: scale(1.03) rotate(1deg); filter: drop-shadow(0 0 35px rgba(var(--accent-rgb),0.55)); }
  100% { opacity: 1; transform: scale(1) rotate(0); filter: drop-shadow(0 0 50px rgba(var(--accent-light-rgb),0.5)); }
}
.intro-text {
  margin-top: 2rem;
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: 0.5em;
  color: var(--text-muted);
  opacity: 0;
  transform: translateY(20px);
  animation: introText 1s ease 1.5s forwards;
}
@keyframes introText {
  to { opacity: 1; transform: translateY(0); letter-spacing: 0.8em; }
}
.intro-line {
  width: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent-light), transparent);
  margin-top: 2rem;
  animation: introLine 1s ease 2s forwards;
}
@keyframes introLine { to { width: 160px; } }
.intro-logo.exit { animation: introLogoExit 0.6s cubic-bezier(0.22, 1, 0.36, 1) forwards; }
@keyframes introLogoExit {
  0%   { opacity: 1; transform: scale(1) rotate(0); }
  100% { opacity: 0; transform: scale(1.5) rotate(0); filter: drop-shadow(0 0 80px rgba(var(--accent-light-rgb),0.8)); }
}

/* ===== Particle background ===== */
.large-header {
  position: fixed;
  inset: 0;
  width: 100vw; height: 100vh;
  background: var(--bg);
  overflow: hidden;
  z-index: 0;
  pointer-events: none;
}
.large-header.demo-1 { background-image: none; }
.large-header canvas {
  position: absolute;
  inset: 0;
  display: block;
  width: 100%;
  height: 100%;
  opacity: 0.9;
}

body > *:not(.intro):not(.large-header):not(.nav) {
  position: relative;
  z-index: 1;
}

/* ===== Subpage framework ===== */
.page-main {
  position: relative;
  z-index: 2;
  min-height: 100vh;
  padding: 138px 5vw 72px;
  display: flex;
  justify-content: center;
  text-align: center;
}
.page-content {
  width: min(900px, 100%);
}
.page-kicker {
  margin-bottom: 0.75rem;
  color: var(--accent-light);
  font-size: 0.78rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
}
.page-title {
  color: var(--text);
  font-size: clamp(2.2rem, 6vw, 4.2rem);
  line-height: 1.1;
  font-weight: 750;
  letter-spacing: 0.08em;
}
.page-placeholder {
  max-width: 560px;
  margin: 1.35rem auto 0;
  color: var(--text-muted);
  font-size: 1rem;
}

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .about-grid, .portfolio-grid, .services-grid { grid-template-columns: 1fr; }
  .about-stats { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 640px) {
  .theme-toggle { margin-right: 10px; }
  .hero-title { font-size: 2.4rem; }
  .btn-outline { margin-left: 0; margin-top: 1rem; }
  .hero-buttons { display: flex; flex-direction: column; align-items: center; }
  .about-stats { grid-template-columns: 1fr; }
  .footer { flex-direction: column; text-align: center; }
}