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

:root {
  --color-primary: #E53935;
  --color-primary-dark: #C62828;
  --color-secondary: #FFCA28;
  --color-secondary-dark: #FFB300;
  --color-bg-light: #FFFFFF;
  --color-bg-dark: #424242;
  --color-bg-warm: #F5F0EB;
  --color-text-primary: #212121;
  --color-text-inverse: #FFFFFF;
  --color-accent-line: rgba(229, 57, 53, 0.4);
  --color-border-light: rgba(33, 33, 33, 0.1);
  --font-heading: 'Noto Sans SC', 'Helvetica Neue', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-body: 'Noto Sans SC', 'Helvetica Neue', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-data: 'JetBrains Mono', 'Courier New', monospace;
  --header-height: 72px;
  --max-width: 1280px;
  --gap: 24px;
  --radius: 4px;
  --transition: 0.25s ease;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  font-size: 18px;
  line-height: 1.6;
  color: var(--color-text-primary);
  background-color: var(--color-bg-light);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

ul,
ol {
  list-style: none;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition);
}

a:hover {
  color: var(--color-primary);
}

a:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: var(--radius);
}

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

button:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: var(--radius);
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: bold;
  line-height: 1.2;
  color: var(--color-text-primary);
}

h1 { font-size: 56px; }
h2 { font-size: 40px; }
h3 { font-size: 32px; }
h4 { font-size: 24px; }

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

.skip-link {
  position: absolute;
  top: -999px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 10000;
  padding: 12px 24px;
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
  font-weight: bold;
  border-radius: 0 0 var(--radius) var(--radius);
  white-space: nowrap;
}

.skip-link:focus {
  top: 0;
}

.progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  width: 0%;
  height: 3px;
  background-color: var(--color-primary);
  z-index: 9999;
  transition: width 0.1s linear;
  will-change: width;
}

@media (prefers-reduced-motion: reduce) {
  .progress-bar {
    transition: none;
  }
  html {
    scroll-behavior: auto;
  }
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--color-bg-light);
  border-bottom: 1px solid var(--color-accent-line);
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
  height: var(--header-height);
  display: flex;
  align-items: center;
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--gap);
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.brand {
  display: flex;
  align-items: center;
  flex-shrink: 0;
}

.brand-link {
  font-family: var(--font-heading);
  font-size: 28px;
  font-weight: bold;
  color: var(--color-primary);
  letter-spacing: 1px;
  display: flex;
  align-items: center;
  gap: 8px;
  position: relative;
}

.brand-link:hover {
  color: var(--color-primary-dark);
}

.brand-coord {
  display: inline-block;
  width: 8px;
  height: 8px;
  background-color: var(--color-primary);
  border-radius: 50%;
  position: relative;
  top: -6px;
  box-shadow: 0 0 0 2px rgba(229, 57, 53, 0.25);
}

.main-nav {
  display: flex;
  align-items: center;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-list li {
  position: relative;
}

.nav-list a {
  display: block;
  padding: 8px 16px;
  font-family: var(--font-heading);
  font-size: 16px;
  font-weight: 600;
  color: var(--color-text-primary);
  border-radius: var(--radius);
  position: relative;
  letter-spacing: 0.5px;
  white-space: nowrap;
}

.nav-list a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 16px;
  right: 16px;
  height: 2px;
  background-color: var(--color-primary);
  transform: scaleX(0);
  transition: transform var(--transition);
}

.nav-list a:hover::after,
.nav-list a:focus-visible::after {
  transform: scaleX(1);
}

.nav-list a[aria-current="page"] {
  color: var(--color-primary);
}

.nav-list a[aria-current="page"]::after {
  transform: scaleX(1);
  background-color: var(--color-primary);
}

.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  padding: 8px;
  border-radius: var(--radius);
  background-color: transparent;
  transition: background-color var(--transition);
  z-index: 1001;
}

.nav-toggle:hover {
  background-color: var(--color-border-light);
}

.hamburger-line {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-text-primary);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
  transform-origin: center;
}

.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }

  .main-nav {
    position: fixed;
    top: 0;
    right: 0;
    width: 100%;
    height: 100vh;
    height: 100dvh;
    background-color: rgba(33, 33, 33, 0.96);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    display: flex;
    align-items: center;
    justify-content: center;
    transform: translateX(100%);
    transition: transform 0.35s cubic-bezier(0.22, 1, 0.36, 1);
    z-index: 999;
    padding: calc(var(--header-height) + 16px) 24px 24px;
    overflow-y: auto;
  }

  .main-nav[data-open] {
    transform: translateX(0);
  }

  .nav-list {
    flex-direction: column;
    gap: 8px;
    width: 100%;
    text-align: center;
  }

  .nav-list a {
    font-size: 24px;
    padding: 16px 24px;
    color: var(--color-text-inverse);
    font-weight: bold;
    letter-spacing: 2px;
    border-radius: 0;
  }

  .nav-list a::after {
    left: 50%;
    right: auto;
    width: 40px;
    transform: translateX(-50%) scaleX(0);
    background-color: var(--color-secondary);
    height: 3px;
    bottom: 4px;
  }

  .nav-list a:hover::after,
  .nav-list a:focus-visible::after {
    transform: translateX(-50%) scaleX(1);
  }

  .nav-list a[aria-current="page"] {
    color: var(--color-secondary);
  }

  .nav-list a[aria-current="page"]::after {
    transform: translateX(-50%) scaleX(1);
    background-color: var(--color-secondary);
  }

  .brand-link {
    font-size: 22px;
  }

  :root {
    --header-height: 64px;
  }

  h1 { font-size: 36px; }
  h2 { font-size: 28px; }
  h3 { font-size: 22px; }
  h4 { font-size: 18px; }
  body { font-size: 16px; }
}

@media (min-width: 769px) and (max-width: 1024px) {
  .nav-list a {
    padding: 8px 12px;
    font-size: 15px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .main-nav {
    transition: none;
  }
  .hamburger-line {
    transition: none;
  }
  .nav-list a::after {
    transition: none;
  }
}

.site-footer {
  position: relative;
  background-color: var(--color-bg-dark);
  color: var(--color-text-inverse);
  padding: 60px 0 28px;
  overflow: hidden;
}

.footer-grid-lines {
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0.06;
  background-image:
    linear-gradient(to right, var(--color-text-inverse) 1px, transparent 1px),
    linear-gradient(to bottom, var(--color-text-inverse) 1px, transparent 1px);
  background-size: 48px 48px;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--gap);
  display: grid;
  grid-template-columns: 1.2fr 1.4fr 1fr;
  gap: 40px 48px;
  position: relative;
  z-index: 1;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-brand-link {
  font-family: var(--font-heading);
  font-size: 28px;
  font-weight: bold;
  color: var(--color-text-inverse);
  letter-spacing: 1px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.footer-brand-link:hover {
  color: var(--color-secondary);
}

.footer-tagline {
  font-size: 15px;
  line-height: 1.6;
  color: rgba(255, 255, 255, 0.65);
  max-width: 280px;
}

.footer-heading {
  font-size: 16px;
  font-weight: bold;
  color: var(--color-text-inverse);
  margin-bottom: 16px;
  letter-spacing: 1px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-primary);
  display: inline-block;
}

.footer-contact-list,
.footer-link-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-contact-list li,
.footer-link-list li {
  font-size: 15px;
  line-height: 1.6;
  color: rgba(255, 255, 255, 0.8);
}

.footer-contact-list a,
.footer-link-list a {
  color: rgba(255, 255, 255, 0.8);
  transition: color var(--transition);
}

.footer-contact-list a:hover,
.footer-link-list a:hover {
  color: var(--color-secondary);
}

.footer-note {
  font-size: 13px;
  color: rgba(255, 255, 255, 0.5);
  margin-top: 16px;
  line-height: 1.6;
  max-width: 320px;
}

.footer-bottom {
  grid-column: 1 / -1;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  padding-top: 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  margin-top: 8px;
}

.footer-icp {
  font-size: 13px;
  color: rgba(255, 255, 255, 0.5);
  font-family: var(--font-data);
  letter-spacing: 0.5px;
}

.footer-copyright {
  font-size: 13px;
  color: rgba(255, 255, 255, 0.5);
}

@media (max-width: 768px) {
  .site-footer {
    padding: 40px 0 20px;
  }

  .footer-inner {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .footer-brand-link {
    font-size: 24px;
  }

  .footer-tagline {
    max-width: 100%;
  }

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

  .footer-note {
    max-width: 100%;
  }
}

@media (min-width: 769px) and (max-width: 1024px) {
  .footer-inner {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }
  .footer-bottom {
    grid-column: 1 / -1;
  }
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--gap);
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  font-family: var(--font-heading);
  font-size: 16px;
  font-weight: bold;
  color: var(--color-text-inverse);
  background-color: var(--color-primary);
  border-radius: var(--radius);
  transition: background-color var(--transition), transform var(--transition);
  letter-spacing: 0.5px;
  min-height: 48px;
}

.btn-primary:hover {
  background-color: var(--color-primary-dark);
  color: var(--color-text-inverse);
  transform: translateY(-1px);
}

.btn-primary:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  font-family: var(--font-heading);
  font-size: 16px;
  font-weight: bold;
  color: var(--color-text-primary);
  background-color: var(--color-secondary);
  border-radius: var(--radius);
  transition: background-color var(--transition), transform var(--transition);
  letter-spacing: 0.5px;
  min-height: 48px;
}

.btn-secondary:hover {
  background-color: var(--color-secondary-dark);
  color: var(--color-text-primary);
  transform: translateY(-1px);
}

.btn-secondary:focus-visible {
  outline: 2px solid var(--color-secondary);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  .btn-primary,
  .btn-secondary {
    transition: none;
  }
  .btn-primary:hover,
  .btn-secondary:hover {
    transform: none;
  }
}

.img-container {
  position: relative;
  width: 100%;
  padding-bottom: 56.25%;
  background-color: var(--color-bg-warm);
  border-radius: var(--radius);
  overflow: hidden;
}

.img-container img,
.img-container picture {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

[data-section] {
  transition: opacity 0.4s ease, transform 0.4s ease;
}

[data-section]:not([data-active]) {
  opacity: 0.3;
  transform: translateY(8px);
}

[data-section][data-active] {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  [data-section] {
    transition: none;
    opacity: 1 !important;
    transform: none !important;
  }
}

::marker {
  color: var(--color-primary);
}

@media (max-width: 480px) {
  :root {
    --gap: 16px;
  }
  .brand-link {
    font-size: 20px;
  }
}