:root {
  --md-primary: #006A5B;
  --md-on-primary: #FFFFFF;
  --md-primary-container: #74F8DC;
  --md-on-primary-container: #00201A;
  --md-secondary: #4A635D;
  --md-on-secondary: #FFFFFF;
  --md-secondary-container: #CDE8E0;
  --md-on-secondary-container: #06201B;
  --md-tertiary: #456179;
  --md-on-tertiary: #FFFFFF;
  --md-tertiary-container: #C8E6FF;
  --md-on-tertiary-container: #001E30;
  --md-error: #BA1A1A;
  --md-on-error: #FFFFFF;
  --md-error-container: #FFDAD6;
  --md-on-error-container: #410002;
  --md-background: #F5FBF7;
  --md-on-background: #161D1B;
  --md-surface: #F5FBF7;
  --md-on-surface: #161D1B;
  --md-surface-variant: #DAE5E0;
  --md-on-surface-variant: #3F4945;
  --md-surface-container-lowest: #FFFFFF;
  --md-surface-container-low: #EFF5F1;
  --md-surface-container: #E9EFEB;
  --md-surface-container-high: #E4E9E5;
  --md-surface-container-highest: #DEE3DF;
  --md-outline: #707975;
  --md-outline-variant: #BEC9C4;
  --md-inverse-surface: #2B322F;
  --md-inverse-on-surface: #EFF1ED;
  --md-inverse-primary: #54DBC0;
  --md-shadow: rgba(0, 0, 0, 0.15);
  --md-surface-tint: #006A5B;
  --md-scrim: rgba(0, 0, 0, 0.6);

  --md-state-hover: rgba(0, 0, 0, 0.08);
  --md-state-focus: rgba(0, 0, 0, 0.12);
  --md-state-pressed: rgba(0, 0, 0, 0.12);
  --md-state-dragged: rgba(0, 0, 0, 0.16);

  --color-bg: var(--md-background);
  --color-card: var(--md-surface-container-low);
  --color-text: var(--md-on-surface);
  --color-link: var(--md-primary);
  --color-link-hover: var(--md-on-primary-container);
  --color-accent: var(--md-secondary-container);
  --color-border: var(--md-outline-variant);
  --color-code-bg: var(--md-inverse-surface);
  --color-code-text: var(--md-inverse-on-surface);
  --color-quote-bg: var(--md-surface-container-high);
  --color-danger: var(--md-error);
  --color-warning: #7C5800;
  --color-wash: var(--md-surface-container);

  --font-serif: 'MiSans', 'Noto Serif SC', 'SimSun', serif;
  --font-sans: 'MiSans', 'PingFang SC', 'Microsoft YaHei', sans-serif;

  --md-elevation-1: 0 1px 2px rgba(0,0,0,0.3), 0 1px 3px 1px rgba(0,0,0,0.15);
  --md-elevation-2: 0 1px 2px rgba(0,0,0,0.3), 0 2px 6px 2px rgba(0,0,0,0.15);
  --md-elevation-3: 0 1px 3px rgba(0,0,0,0.3), 0 4px 8px 3px rgba(0,0,0,0.15);
  --md-elevation-4: 0 2px 3px rgba(0,0,0,0.3), 0 6px 10px 4px rgba(0,0,0,0.15);

  --shadow-sm: var(--md-elevation-1);
  --shadow-md: var(--md-elevation-2);
  --shadow-lg: var(--md-elevation-3);

  --radius-xs: 4px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 28px;
  --radius-full: 9999px;
  --transition: 0.2s cubic-bezier(0.2, 0, 0, 1);
  --transition-emphasized: 0.35s cubic-bezier(0.2, 0, 0, 1);
}

[data-theme="dark"] {
  --md-primary: #54DBC0;
  --md-on-primary: #00382F;
  --md-primary-container: #005144;
  --md-on-primary-container: #74F8DC;
  --md-secondary: #B1CCC4;
  --md-on-secondary: #1B352F;
  --md-secondary-container: #324B45;
  --md-on-secondary-container: #CDE8E0;
  --md-tertiary: #AACAE5;
  --md-on-tertiary: #113348;
  --md-tertiary-container: #2D4A60;
  --md-on-tertiary-container: #C8E6FF;
  --md-error: #FFB4AB;
  --md-on-error: #690005;
  --md-error-container: #93000A;
  --md-on-error-container: #FFDAD6;
  --md-background: #0E1513;
  --md-on-background: #E0E3E1;
  --md-surface: #0E1513;
  --md-on-surface: #E0E3E1;
  --md-surface-variant: #3F4945;
  --md-on-surface-variant: #BEC9C4;
  --md-surface-container-lowest: #090F0D;
  --md-surface-container-low: #161D1B;
  --md-surface-container: #1A2120;
  --md-surface-container-high: #252B2A;
  --md-surface-container-highest: #303635;
  --md-outline: #899390;
  --md-outline-variant: #3F4945;
  --md-inverse-surface: #E0E3E1;
  --md-inverse-on-surface: #2B322F;
  --md-inverse-primary: #006A5B;
  --md-shadow: rgba(0, 0, 0, 0.3);
  --md-surface-tint: #54DBC0;
  --md-scrim: rgba(0, 0, 0, 0.6);

  --md-state-hover: rgba(255, 255, 255, 0.08);
  --md-state-focus: rgba(255, 255, 255, 0.12);
  --md-state-pressed: rgba(255, 255, 255, 0.12);
  --md-state-dragged: rgba(255, 255, 255, 0.16);

  --color-warning: #FFB870;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  transition: background-color var(--transition), color var(--transition);
}

.container {
  width: 100%;
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
}

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

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--md-surface-container);
  border-bottom: none;
  transition: background-color var(--transition);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: 0.04em;
}

.logo-svg {
  flex-shrink: 0;
  transition: transform var(--transition);
}

.logo:hover .logo-svg {
  transform: rotate(-6deg) scale(1.05);
}

.logo-bg {
  fill: var(--md-primary);
  transition: fill var(--transition);
}

.logo:hover .logo-bg {
  fill: var(--md-on-primary-container);
}

.main-nav {
  display: flex;
  gap: 8px;
}

.nav-link {
  position: relative;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--md-on-surface-variant);
  padding: 8px 16px;
  border-radius: var(--radius-full);
  transition: background-color var(--transition), color var(--transition);
}

.nav-link::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background-color: transparent;
  transition: background-color var(--transition);
  pointer-events: none;
  z-index: -1;
}

.nav-link:hover {
  color: var(--md-on-surface);
}

.nav-link:hover::before {
  background-color: var(--md-state-hover);
}

.nav-link:focus-visible::before {
  background-color: var(--md-state-focus);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.theme-toggle {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: none;
  background-color: transparent;
  color: var(--md-on-surface-variant);
  cursor: pointer;
  font-size: 1.1rem;
  transition: background-color var(--transition), color var(--transition);
  overflow: hidden;
}

.theme-toggle::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background-color: transparent;
  transition: background-color var(--transition);
  pointer-events: none;
}

.theme-toggle:hover {
  color: var(--md-on-surface);
}

.theme-toggle:hover::before {
  background-color: var(--md-state-hover);
}

.theme-toggle:focus-visible::before {
  background-color: var(--md-state-focus);
}

.theme-icon {
  position: absolute;
  transition: opacity var(--transition), transform var(--transition);
}

[data-theme="light"] .dark-icon,
[data-theme="dark"] .light-icon {
  opacity: 0;
  transform: scale(0.5);
}

[data-theme="light"] .light-icon,
[data-theme="dark"] .dark-icon {
  opacity: 1;
  transform: scale(1);
}

.mobile-menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  border: none;
  background: transparent;
  cursor: pointer;
}

.mobile-menu-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-text);
  transition: transform 0.3s ease, opacity 0.3s ease;
}

.mobile-menu-toggle.active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.mobile-menu-toggle.active span:nth-child(2) {
  opacity: 0;
}

.mobile-menu-toggle.active span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.hero {
  padding: 96px 0 120px;
  overflow: hidden;
}

.hero .container {
  text-align: center;
}

.hero-content {
  max-width: 640px;
  margin: 0 auto;
}

.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 24px;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--md-outline-variant);
  background-color: var(--md-surface-container-highest);
  color: var(--md-on-surface-variant);
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.04em;
}

.hero-title {
  font-family: var(--font-sans);
  font-size: clamp(2.5rem, 5vw, 3.5rem);
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: -0.02em;
  white-space: nowrap;
  margin-bottom: 20px;
  color: var(--md-on-surface);
}

.hero-description {
  font-size: 1.05rem;
  color: var(--md-on-surface-variant);
  margin-bottom: 40px;
  line-height: 1.6;
}

.hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: center;
}

.btn {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 24px;
  height: 44px;
  border-radius: var(--radius-full);
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
  transition: box-shadow var(--transition-emphasized), background-color var(--transition), color var(--transition);
  border: none;
  letter-spacing: 0.01em;
  overflow: hidden;
}

.btn::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background-color: transparent;
  transition: background-color var(--transition);
  pointer-events: none;
}

.btn:hover::before {
  background-color: var(--md-state-hover);
}

.btn:focus-visible::before {
  background-color: var(--md-state-focus);
}

.btn:active::before {
  background-color: var(--md-state-pressed);
}

.btn-primary {
  background-color: var(--md-primary);
  color: var(--md-on-primary);
  box-shadow: var(--md-elevation-1);
}

.btn-primary:hover {
  box-shadow: var(--md-elevation-2);
}

.btn-primary::before {
  background-color: var(--md-on-primary);
  opacity: 0;
}

.btn-primary:hover::before {
  opacity: 0.08;
}

.btn-primary:focus-visible::before {
  opacity: 0.12;
}

.btn-primary:active::before {
  opacity: 0.12;
}

.btn-secondary {
  background-color: transparent;
  color: var(--md-primary);
  border: 1px solid var(--md-outline);
}

.btn-secondary:hover {
  background-color: var(--md-primary);
  color: var(--md-on-primary);
  border-color: transparent;
}

.btn-secondary::before {
  background-color: var(--md-on-primary);
  opacity: 0;
}

.btn-secondary:hover::before {
  opacity: 0.08;
}

.hero-visual {
  display: flex;
  align-items: center;
  justify-content: center;
}

.deco-shape {
  fill: var(--md-primary);
  opacity: 0.3;
  transition: fill var(--transition), opacity var(--transition);
}

.section-header {
  text-align: center;
  margin-bottom: 56px;
}

.section-title {
  font-family: var(--font-sans);
  font-size: clamp(1.75rem, 3vw, 2.25rem);
  font-weight: 600;
  line-height: 1.2;
  margin-bottom: 12px;
  color: var(--md-on-surface);
  letter-spacing: -0.01em;
}

.projects {
  padding: 80px 0;
}

.project-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}

.project-card {
  position: relative;
  padding: 24px;
  background-color: var(--md-surface-container-low);
  border: none;
  border-radius: var(--radius-md);
  box-shadow: var(--md-elevation-1);
  transition: box-shadow var(--transition-emphasized), background-color var(--transition);
  overflow: hidden;
}

.project-card:hover {
  box-shadow: var(--md-elevation-3);
  background-color: var(--md-surface-container);
}

.project-card::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background-color: var(--md-on-surface);
  opacity: 0;
  transition: opacity var(--transition);
  pointer-events: none;
}

.project-card:hover::before {
  opacity: 0.08;
}

.project-meta {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
}

.project-tag,
.project-status {
  display: inline-flex;
  align-items: center;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.01em;
  height: 24px;
  box-sizing: border-box;
}

.project-tag {
  background-color: var(--md-secondary-container);
  color: var(--md-on-secondary-container);
}

.project-status {
  background-color: var(--md-surface-container-highest);
  color: var(--md-on-surface-variant);
}

.project-title {
  font-family: var(--font-sans);
  font-size: 1.4rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--md-on-surface);
  letter-spacing: -0.01em;
}

.project-desc {
  font-size: 0.9rem;
  color: var(--md-on-surface-variant);
  margin-bottom: 20px;
  line-height: 1.5;
}

.project-links {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.project-link {
  position: relative;
  display: inline-flex;
  align-items: center;
  padding: 6px 12px;
  margin: -6px -12px;
  border-radius: var(--radius-full);
  font-weight: 500;
  font-size: 0.85rem;
  color: var(--md-primary);
  transition: background-color var(--transition), color var(--transition);
}

.project-link::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background-color: var(--md-primary);
  opacity: 0;
  transition: opacity var(--transition);
  pointer-events: none;
}

.project-link:hover {
  color: var(--md-on-primary);
}

.project-link:hover::before {
  opacity: 0.08;
}

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

.site-footer {
  padding: 48px 0;
  border-top: none;
  background-color: var(--md-surface-container-low);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 20px;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 600;
  color: var(--md-on-surface);
}

.footer-nav {
  display: flex;
  gap: 4px;
}

.footer-nav a {
  position: relative;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--md-on-surface-variant);
  padding: 8px 12px;
  border-radius: var(--radius-full);
  transition: background-color var(--transition), color var(--transition);
}

.footer-nav a::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background-color: var(--md-state-hover);
  opacity: 0;
  transition: opacity var(--transition);
  pointer-events: none;
}

.footer-nav a:hover {
  color: var(--md-on-surface);
}

.footer-nav a:hover::before {
  opacity: 1;
}

.footer-copy {
  font-size: 0.85rem;
  color: var(--md-on-surface-variant);
  opacity: 0.7;
}

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

@media (max-width: 720px) {
  .main-nav {
    position: fixed;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    padding: 16px 24px;
    background-color: var(--md-surface-container);
    border-bottom: none;
    box-shadow: var(--md-elevation-2);
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: transform var(--transition-emphasized), opacity var(--transition);
    z-index: 99;
  }

  .main-nav.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav-link {
    padding: 14px 16px;
    border-bottom: none;
    border-radius: var(--radius-full);
    width: 100%;
    box-sizing: border-box;
  }

  .nav-link:last-child {
    border-bottom: none;
  }

  .mobile-menu-toggle {
    display: flex;
  }

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