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

:root {
  --primary-bg: #0a0a1a;
  --secondary-bg: #1a1a2e;
  --accent-red: #e63946;
  --accent-yellow: #f9c74f;
  --text-white: #ffffff;
  --text-gray: #8d99ae;
  --border-light: #2b2d42;
  --error: #d90429;

  --font-heading: 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-body: 'Noto Sans SC', 'Roboto', 'PingFang SC', 'Microsoft YaHei', sans-serif;

  --nav-height: 64px;
  --left-panel-width: 300px;
  --container-max: 1200px;
  --gap-base: 16px;
  --gap-lg: 32px;
  --radius-pill: 999px;
  --radius-card: 4px;
  --transition-fast: 0.2s ease;
  --transition-reveal: 0.5s cubic-bezier(0.23, 1, 0.32, 1);
}

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

body {
  font-family: var(--font-body);
  font-weight: 400;
  font-size: 16px;
  line-height: 1.6;
  background-color: var(--primary-bg);
  color: var(--text-white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

:focus-visible {
  outline: 2px solid var(--accent-yellow);
  outline-offset: 2px;
}

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

a:hover {
  color: var(--accent-yellow);
}

ul, ol {
  list-style: none;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

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

/* ===== Skip Link ===== */
.skip-link {
  position: fixed;
  top: -100%;
  left: 0;
  z-index: 9999;
  padding: 12px 24px;
  background: var(--accent-red);
  color: #fff;
  font-weight: 700;
  font-size: 14px;
  transition: top 0.2s ease;
}

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

/* ===== Site Header ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--primary-bg);
  border-bottom: 1px solid var(--border-light);
}

.header__inner {
  display: flex;
  align-items: stretch;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--gap-base);
  min-height: var(--nav-height);
}

.header__left {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
  width: var(--left-panel-width);
  padding-right: var(--gap-lg);
  border-right: 1px solid var(--border-light);
}

.header__left .brand {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 22px;
  letter-spacing: -0.02em;
  color: var(--text-white);
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.header__left .brand::after {
  content: '';
  display: inline-block;
  width: 6px;
  height: 6px;
  background: var(--accent-red);
  border-radius: 0;
  transform: rotate(45deg);
}

.header__badge {
  font-size: 11px;
  color: var(--text-gray);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  border-left: 2px solid var(--accent-red);
  padding-left: 8px;
  line-height: 1.2;
  display: none;
}

.header__right {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: flex-end;
  padding-left: var(--gap-lg);
}

.header__nav {
  display: flex;
  align-items: center;
  gap: var(--gap-base);
}

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

.nav__item {
  position: relative;
}

.nav__link {
  display: inline-flex;
  align-items: center;
  padding: 8px 18px;
  font-family: var(--font-heading);
  font-weight: 500;
  font-size: 14px;
  color: var(--text-gray);
  border: 1px solid transparent;
  border-radius: var(--radius-pill);
  transition: all var(--transition-fast);
  letter-spacing: 0.02em;
}

.nav__link:hover {
  color: var(--text-white);
  border-color: var(--border-light);
  background: rgba(255,255,255,0.04);
}

.nav__link[aria-current="page"] {
  color: var(--text-white);
  background: rgba(230,57,70,0.15);
  border-color: var(--accent-red);
}

.nav__link[aria-current="page"]::before {
  content: '●';
  font-size: 8px;
  color: var(--accent-red);
  margin-right: 6px;
  display: inline-block;
}

.header__cta {
  margin-left: 8px;
  flex-shrink: 0;
}

.header__nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 44px;
  height: 44px;
  gap: 5px;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-card);
  background: transparent;
  padding: 8px;
  cursor: pointer;
  transition: border-color var(--transition-fast);
}

.header__nav-toggle:hover {
  border-color: var(--accent-red);
}

.hamburger-line {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-white);
  border-radius: 1px;
  transition: transform 0.3s ease, opacity 0.3s ease;
}

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

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

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

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 28px;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 14px;
  letter-spacing: 0.03em;
  border-radius: var(--radius-pill);
  transition: all var(--transition-fast);
  text-align: center;
  white-space: nowrap;
}

.btn--primary {
  background: var(--accent-red);
  color: #fff;
  border: 1px solid var(--accent-red);
}

.btn--primary:hover {
  background: #c1121f;
  border-color: #c1121f;
  color: #fff;
}

.btn--outline {
  background: transparent;
  color: var(--text-white);
  border: 1px solid var(--border-light);
}

.btn--outline:hover {
  border-color: var(--accent-yellow);
  color: var(--accent-yellow);
}

.btn--small {
  padding: 6px 16px;
  font-size: 12px;
}

/* ===== Breadcrumb ===== */
.breadcrumb {
  padding: 16px 0;
  font-size: 13px;
  color: var(--text-gray);
}

.breadcrumb__list {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 4px;
}

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

.breadcrumb__item a {
  color: var(--text-gray);
}

.breadcrumb__item a:hover {
  color: var(--accent-yellow);
}

.breadcrumb__item[aria-current="page"] {
  color: var(--text-white);
  font-weight: 500;
}

.breadcrumb__sep {
  display: inline-block;
  color: var(--border-light);
  font-size: 12px;
  margin: 0 4px;
}

/* ===== Container ===== */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--gap-base);
}

.container--narrow {
  max-width: 840px;
}

/* ===== Section ===== */
.section {
  padding: 64px 0;
}

.section__header {
  display: flex;
  align-items: baseline;
  gap: 16px;
  margin-bottom: 32px;
}

.section__number {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 48px;
  line-height: 1;
  color: var(--accent-red);
  letter-spacing: -0.04em;
  opacity: 0.6;
}

.section__title {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 28px;
  letter-spacing: -0.02em;
  color: var(--text-white);
}

.section__body {
  color: var(--text-gray);
  line-height: 1.8;
}

/* ===== Card ===== */
.card {
  background: var(--secondary-bg);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-card);
  padding: 24px;
  transition: border-color var(--transition-fast), transform var(--transition-fast);
}

.card:hover {
  border-color: var(--accent-red);
  transform: translateY(-2px);
}

.card__title {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 18px;
  margin-bottom: 8px;
  color: var(--text-white);
}

.card__body {
  font-size: 14px;
  color: var(--text-gray);
  line-height: 1.7;
}

/* ===== Grid ===== */
.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--gap-lg);
}

.grid-3 {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: var(--gap-lg);
}

.gap-sm { gap: var(--gap-base); }
.gap-lg { gap: var(--gap-lg); }

/* ===== Footer ===== */
.site-footer {
  background: var(--secondary-bg);
  border-top: 1px solid var(--border-light);
  padding: 48px 0 32px;
  margin-top: 64px;
}

.footer__inner {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--gap-base);
  display: grid;
  grid-template-columns: 1.2fr 1fr 1.2fr 1fr;
  gap: 32px;
}

.footer__col .brand {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 20px;
  color: var(--text-white);
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.footer__col .brand::after {
  content: '';
  display: inline-block;
  width: 5px;
  height: 5px;
  background: var(--accent-red);
  transform: rotate(45deg);
}

.footer__tagline {
  font-size: 12px;
  color: var(--text-gray);
  margin-top: 8px;
  letter-spacing: 0.06em;
}

.footer__heading {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 14px;
  color: var(--text-white);
  margin-bottom: 16px;
  letter-spacing: 0.04em;
  border-bottom: 1px solid var(--border-light);
  padding-bottom: 8px;
}

.footer__link-group {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer__link {
  font-size: 14px;
  color: var(--text-gray);
  transition: color var(--transition-fast), padding-left var(--transition-fast);
}

.footer__link:hover {
  color: var(--accent-yellow);
  padding-left: 4px;
}

.footer__contact-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 13px;
  color: var(--text-gray);
}

.footer__contact-list a {
  color: var(--text-gray);
}

.footer__contact-list a:hover {
  color: var(--accent-yellow);
}

.footer__icp {
  font-size: 12px;
  color: var(--text-gray);
  margin-bottom: 8px;
}

.footer__trust {
  font-size: 11px;
  color: rgba(141,153,174,0.6);
  line-height: 1.5;
}

/* ===== Scroll Progress ===== */
[data-scroll-progress] {
  position: fixed;
  top: 0;
  left: 0;
  width: 0%;
  height: 3px;
  background: linear-gradient(90deg, var(--accent-red), var(--accent-yellow));
  z-index: 1001;
  transition: width 0.1s linear;
  pointer-events: none;
}

/* ===== Back to Top ===== */
[data-back-to-top] {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 48px;
  height: 48px;
  background: var(--secondary-bg);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-card);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  color: var(--text-gray);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(16px);
  transition: opacity 0.3s ease, transform 0.3s ease, visibility 0.3s ease, border-color var(--transition-fast);
  z-index: 999;
}

[data-back-to-top].is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

[data-back-to-top]:hover {
  border-color: var(--accent-red);
  color: var(--accent-red);
}

/* ===== Reveal Animations ===== */
[data-reveal] {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s cubic-bezier(0.23, 1, 0.32, 1), transform 0.6s cubic-bezier(0.23, 1, 0.32, 1);
}

[data-reveal].is-visible {
  opacity: 1;
  transform: translateY(0);
}

[data-reveal][data-reveal-delay="100"] { transition-delay: 0.1s; }
[data-reveal][data-reveal-delay="200"] { transition-delay: 0.2s; }
[data-reveal][data-reveal-delay="300"] { transition-delay: 0.3s; }

/* ===== Reduced Motion ===== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  html {
    scroll-behavior: auto;
  }

  [data-reveal] {
    opacity: 1;
    transform: none;
  }

  [data-back-to-top] {
    transition: none;
  }
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .footer__inner {
    grid-template-columns: 1fr 1fr;
    gap: 24px;
  }

  .header__left {
    width: auto;
    border-right: none;
    padding-right: 0;
  }

  .header__badge {
    display: inline-block;
  }
}

@media (max-width: 768px) {
  :root {
    --nav-height: 56px;
    --gap-lg: 24px;
  }

  .header__inner {
    padding: 0 12px;
  }

  .header__left {
    flex: 1;
  }

  .header__left .brand {
    font-size: 18px;
  }

  .header__badge {
    display: none;
  }

  .header__right {
    padding-left: 0;
  }

  .header__nav-toggle {
    display: flex;
  }

  .header__nav {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--primary-bg);
    border-bottom: 2px solid var(--accent-red);
    flex-direction: column;
    align-items: stretch;
    padding: 16px;
    gap: 8px;
    transform: translateY(-120%);
    opacity: 0;
    visibility: hidden;
    transition: transform 0.35s ease, opacity 0.35s ease, visibility 0.35s ease;
    box-shadow: 0 16px 32px rgba(0,0,0,0.6);
  }

  .header__nav[data-open] {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav__list {
    flex-direction: column;
    gap: 4px;
  }

  .nav__link {
    padding: 12px 16px;
    border-radius: var(--radius-card);
    width: 100%;
  }

  .header__cta {
    margin-left: 0;
    margin-top: 8px;
    width: 100%;
    justify-content: center;
  }

  .section {
    padding: 40px 0;
  }

  .section__number {
    font-size: 36px;
  }

  .section__title {
    font-size: 22px;
  }

  .grid-2,
  .grid-3 {
    grid-template-columns: 1fr;
  }

  .footer__inner {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .footer__col {
    text-align: left;
  }

  [data-back-to-top] {
    bottom: 20px;
    right: 20px;
    width: 42px;
    height: 42px;
  }
}

@media (max-width: 480px) {
  .header__left .brand {
    font-size: 16px;
  }

  .btn {
    padding: 8px 20px;
    font-size: 13px;
  }

  .section {
    padding: 32px 0;
  }

  .section__title {
    font-size: 20px;
  }
}

/* ===== Image Container Base ===== */
.img-container {
  position: relative;
  overflow: hidden;
  background: var(--secondary-bg);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-card);
}

.img-container::before {
  content: '';
  display: block;
  padding-bottom: 56.25%;
}

.img-container img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.img-container--portrait::before {
  padding-bottom: 133%;
}

.img-container--square::before {
  padding-bottom: 100%;
}