/* ===== Reset & Tokens ===== */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --c-bg: #0A1E3C;
  --c-bg-deep: #061224;
  --c-panel: #12294D;
  --c-accent: #FF6B00;
  --c-accent-soft: #FF9A5C;
  --c-text: #E0F7FA;
  --c-text-dim: #B0BEC5;
  --c-positive: #00E676;
  --c-negative: #FF5252;
  --c-border: #2D3E5F;
  --font-display: Impact, "Arial Black", "Noto Sans CJK SC", "Source Han Sans SC", "Microsoft YaHei", sans-serif;
  --font-mono: "Roboto Mono", "SF Mono", "Noto Sans Mono", "Source Han Mono", monospace;
  --container-w: 1280px;
  --header-h: 68px;
  --space-section: 80px;
}

html {
  color-scheme: dark;
  scroll-behavior: smooth;
}

body {
  background:
    linear-gradient(rgba(45, 62, 95, 0.12) 1px, transparent 1px) 0 0 / 40px 40px,
    linear-gradient(90deg, rgba(45, 62, 95, 0.12) 1px, transparent 1px) 0 0 / 40px 40px,
    var(--c-bg);
  color: var(--c-text);
  font-family: var(--font-mono);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.2;
  color: #fff;
  letter-spacing: 0.02em;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color 0.2s ease, background 0.2s ease, opacity 0.2s ease;
}

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

ul, ol {
  list-style: none;
}

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

:focus-visible {
  outline: 2px dashed var(--c-accent);
  outline-offset: 4px;
  border-radius: 2px;
}

::selection {
  background: var(--c-accent);
  color: #fff;
}

/* ===== Container & Grid ===== */
.container {
  max-width: var(--container-w);
  margin-inline: auto;
  padding-inline: 24px;
}

.section {
  padding-block: var(--space-section);
}

.grid-12 {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: 24px;
}

.card {
  background: var(--c-panel);
  border: 1px solid var(--c-border);
  padding: 32px;
  position: relative;
}

/* ===== Skip Link ===== */
.skip-link {
  position: fixed;
  top: -100%;
  left: 16px;
  z-index: 9999;
  background: var(--c-accent);
  color: #fff;
  padding: 12px 24px;
  font-weight: 700;
  clip-path: polygon(0 0, calc(100% - 12px) 0, 100% 12px, 100% 100%, 12px 100%, 0 calc(100% - 12px));
  transition: top 0.2s ease;
}
.skip-link:focus {
  top: 12px;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 28px;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 14px;
  letter-spacing: 0.08em;
  background: var(--c-panel);
  border: 1px solid var(--c-border);
  color: var(--c-text);
  clip-path: polygon(0 0, calc(100% - 14px) 0, 100% 14px, 100% 100%, 14px 100%, 0 calc(100% - 14px));
  transition: background 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
  position: relative;
}
.btn:hover {
  transform: translateY(-2px);
  background: var(--c-panel);
  border-color: var(--c-accent);
}
.btn--primary {
  background: var(--c-accent);
  border-color: var(--c-accent);
  color: #fff;
}
.btn--primary:hover {
  background: var(--c-accent-soft);
  border-color: var(--c-accent-soft);
}
.btn--sm {
  padding: 12px 20px;
}

/* ===== Header ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(6, 18, 36, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--c-border);
}

.scroll-progress {
  display: block;
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 100%;
  height: 3px;
  background: var(--c-accent);
  transform: scaleX(0);
  transform-origin: 0 50%;
  pointer-events: none;
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: var(--header-h);
  gap: 24px;
}

/* Brand */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  flex-shrink: 0;
}
.brand__mark {
  width: 42px;
  height: 42px;
  background: linear-gradient(135deg, var(--c-accent) 0%, var(--c-accent-soft) 100%);
  clip-path: polygon(0 0, 100% 0, 100% 100%, 12px 100%, 0 calc(100% - 12px));
  position: relative;
  box-shadow: 8px 8px 24px rgba(255, 107, 0, 0.5);
}
.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}
.brand__name {
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: #fff;
}
.brand__slogan {
  font-size: 11px;
  color: var(--c-accent);
  letter-spacing: 0.2em;
  font-family: var(--font-mono);
}

/* Main Nav */
.main-nav ul {
  display: flex;
  gap: 4px;
  counter-reset: nav-index;
}
.main-nav li {
  counter-increment: nav-index;
}
.main-nav a {
  display: block;
  padding: 10px 14px;
  font-size: 14px;
  color: var(--c-text-dim);
  border: 1px solid transparent;
  border-radius: 4px;
  position: relative;
  transition: color 0.2s ease, background 0.2s ease, border-color 0.2s ease;
}
.main-nav a::before {
  content: "[" counter(nav-index, decimal-leading-zero) "]";
  font-size: 11px;
  color: var(--c-accent);
  margin-right: 6px;
  font-weight: 700;
  opacity: 0.8;
}
.main-nav a:hover,
.main-nav a[aria-current="page"] {
  color: #fff;
  background: var(--c-panel);
  border-color: var(--c-border);
}
.main-nav a[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 8px;
  right: 8px;
  bottom: 2px;
  height: 2px;
  background: var(--c-accent);
}

/* Header Actions */
.header__actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

/* Nav Toggle */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 8px;
  background: var(--c-panel);
  border: 1px solid var(--c-border);
  border-radius: 6px;
}
.nav-toggle__bar {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--c-text);
  transition: transform 0.2s ease, background 0.2s ease, opacity 0.2s ease;
}
[data-nav-toggle][aria-expanded="true"] .nav-toggle__bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
[data-nav-toggle][aria-expanded="true"] .nav-toggle__bar:nth-child(2) {
  opacity: 0;
}
[data-nav-toggle][aria-expanded="true"] .nav-toggle__bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ===== Footer ===== */
.site-footer {
  background: var(--c-bg-deep);
  border-top: 4px solid var(--c-accent);
  margin-top: 80px;
}

.footer__grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr;
  gap: 48px;
  padding-block: 56px 40px;
}

.footer__brand-name {
  font-size: 32px;
  color: #fff;
  letter-spacing: 0.04em;
}
.footer__brand-slogan {
  font-size: 14px;
  color: var(--c-accent);
  letter-spacing: 0.24em;
  font-weight: 700;
  margin-bottom: 16px;
}
.footer__trust {
  max-width: 360px;
  font-size: 13px;
  color: var(--c-text-dim);
  line-height: 1.8;
}

.footer__title {
  font-size: 18px;
  color: #fff;
  margin-bottom: 20px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--c-border);
  position: relative;
}
.footer__title::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 40px;
  height: 2px;
  background: var(--c-accent);
}

.footer__nav ul,
.footer__contact ul {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.footer__nav a,
.footer__contact a {
  color: var(--c-text-dim);
  font-size: 14px;
  transition: color 0.2s ease, padding-left 0.2s ease;
}
.footer__nav a:hover,
.footer__contact a:hover {
  color: var(--c-accent);
  padding-left: 8px;
}
.footer__contact li {
  color: var(--c-text-dim);
  font-size: 13px;
  line-height: 1.6;
}

.footer__legal {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding-block: 20px;
  border-top: 1px solid var(--c-border);
  font-size: 12px;
  color: var(--c-text-dim);
}
.footer__legal-links {
  display: flex;
  gap: 24px;
}
.footer__legal-links a {
  color: var(--c-text-dim);
  transition: color 0.2s ease;
}
.footer__legal-links a:hover {
  color: var(--c-accent);
}

/* ===== Responsive ===== */
@media (min-width: 769px) and (max-width: 1024px) {
  .main-nav a {
    padding: 8px;
    font-size: 13px;
  }
  .brand__name {
    font-size: 18px;
  }
  .header__inner {
    gap: 12px;
  }
}

@media (max-width: 768px) {
  body {
    font-size: 15px;
  }

  .site-header {
    position: sticky;
  }

  .header__inner {
    flex-wrap: wrap;
    padding-block: 8px;
    gap: 12px;
  }

  .nav-toggle {
    display: flex;
  }

  .main-nav {
    flex-basis: 100%;
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-12px);
    transition: max-height 0.3s ease, opacity 0.3s ease, transform 0.3s ease, visibility 0.3s;
    background: var(--c-bg-deep);
    border: 1px solid var(--c-border);
    border-radius: 8px;
    padding-inline: 8px;
  }
  .main-nav[data-open] {
    max-height: 80vh;
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
    overflow-y: auto;
  }
  .main-nav ul {
    flex-direction: column;
    padding-block: 8px;
    counter-reset: nav-index;
  }
  .main-nav li {
    counter-increment: nav-index;
  }
  .main-nav a {
    padding: 14px 12px;
    font-size: 16px;
    border-radius: 6px;
  }
  .main-nav a:hover,
  .main-nav a[aria-current="page"] {
    background: var(--c-panel);
  }

  .footer__grid {
    grid-template-columns: 1fr;
    gap: 32px;
    padding-block: 40px 24px;
  }
  .footer__trust {
    max-width: 100%;
  }
  .footer__legal {
    flex-direction: column;
    align-items: flex-start;
    font-size: 12px;
  }
  .footer__legal-links {
    flex-wrap: wrap;
    gap: 12px 24px;
  }
}

/* ===== Reduced Motion ===== */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
  .skip-link,
  .main-nav,
  .btn,
  .brand__mark {
    transition: none;
  }
}