:root {
  --paper: #eef1ed;
  --paper-light: #f8faf7;
  --ink: #18211e;
  --muted: #66716c;
  --line: #c8ceca;
  --green: #075c4c;
  --green-dark: #04473b;
  --red: #d92f35;
  --red-dark: #b92129;
  --steel: #aab4af;
  --white: #ffffff;
  --shadow: 0 30px 70px rgba(19, 43, 35, 0.14);
  --display: "Songti SC", "STSong", "Noto Serif CJK SC", serif;
  --body: "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC", sans-serif;
  --utility: "SFMono-Regular", "Cascadia Mono", "Roboto Mono", monospace;
}

* {
  box-sizing: border-box;
}

html {
  min-width: 320px;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--body);
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  margin: 0;
  background:
    linear-gradient(90deg, rgba(7, 92, 76, 0.045) 1px, transparent 1px) 0 0 / 96px 96px,
    linear-gradient(rgba(7, 92, 76, 0.045) 1px, transparent 1px) 0 0 / 96px 96px,
    var(--paper);
}

body::before {
  position: fixed;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(circle at 14% 18%, rgba(255, 255, 255, 0.86), transparent 26%),
    radial-gradient(circle at 86% 82%, rgba(7, 92, 76, 0.1), transparent 34%);
  content: "";
  pointer-events: none;
}

a {
  color: inherit;
}

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 20;
  padding: 10px 14px;
  border-radius: 4px;
  background: var(--ink);
  color: var(--white);
  font-size: 14px;
  transform: translateY(-150%);
  transition: transform 180ms ease;
}

.skip-link:focus {
  transform: translateY(0);
}

.site-shell {
  display: grid;
  grid-template-rows: auto 1fr auto;
  width: min(1380px, calc(100% - 56px));
  min-height: 100vh;
  margin: 0 auto;
}

.masthead {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 28px 0;
  border-bottom: 1px solid var(--line);
}

.brand {
  display: inline-flex;
  gap: 13px;
  align-items: center;
  text-decoration: none;
}

.brand-mark {
  position: relative;
  display: grid;
  width: 40px;
  height: 40px;
  overflow: hidden;
  border: 1px solid var(--ink);
  border-radius: 50%;
  place-items: center;
  transform: rotate(-12deg);
}

.brand-mark::after {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--paper);
  box-shadow: 0 0 0 1px var(--ink);
  content: "";
}

.brand-mark span {
  position: absolute;
  width: 54px;
  height: 11px;
  background: var(--green);
}

.brand-mark span:last-child {
  height: 5px;
  background: var(--red);
  transform: rotate(90deg);
}

.brand-copy {
  display: grid;
  gap: 2px;
}

.brand-copy strong {
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.brand-copy small,
.release-tag,
.eyebrow,
.checksum,
.footer {
  font-family: var(--utility);
}

.brand-copy small {
  color: var(--muted);
  font-size: 9px;
  letter-spacing: 0.15em;
}

.release-tag {
  display: inline-flex;
  gap: 8px;
  align-items: center;
  color: var(--green);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.release-dot {
  position: relative;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--green);
}

.release-dot::after {
  position: absolute;
  inset: -4px;
  border: 1px solid var(--green);
  border-radius: inherit;
  content: "";
  animation: status-pulse 2.6s ease-out infinite;
}

.hero {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.18fr) minmax(390px, 0.82fr) 46px;
  gap: clamp(48px, 7vw, 112px);
  align-items: center;
  padding: clamp(70px, 10vh, 124px) 0;
}

.hero-copy {
  max-width: 670px;
  animation: reveal-up 700ms 80ms both cubic-bezier(0.22, 1, 0.36, 1);
}

.eyebrow {
  display: flex;
  width: max-content;
  margin: 0 0 30px;
  border: 1px solid var(--line);
  color: var(--muted);
  font-size: 10px;
  letter-spacing: 0.08em;
}

.eyebrow span,
.eyebrow strong {
  padding: 8px 12px;
}

.eyebrow strong {
  border-left: 1px solid var(--line);
  color: var(--ink);
  font-weight: 600;
}

h1 {
  margin: 0;
  font-family: var(--display);
  font-size: clamp(54px, 7.2vw, 110px);
  font-weight: 700;
  line-height: 0.94;
  letter-spacing: -0.06em;
}

h1 span {
  position: relative;
  display: block;
  width: max-content;
  max-width: 100%;
  margin-top: 0.16em;
  color: var(--green);
  font-size: 0.5em;
  line-height: 1.15;
  letter-spacing: -0.025em;
}

h1 span::after {
  position: absolute;
  right: -0.32em;
  bottom: 0.08em;
  width: 0.14em;
  height: 0.14em;
  border-radius: 50%;
  background: var(--red);
  content: "";
}

.intro {
  max-width: 590px;
  margin: 34px 0 0;
  color: #48534e;
  font-size: clamp(16px, 1.35vw, 19px);
  line-height: 1.9;
}

.summary {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  max-width: 620px;
  margin: 48px 0 0;
  border-top: 1px solid var(--line);
}

.summary div {
  padding: 17px 18px 0 0;
}

.summary div + div {
  padding-left: 18px;
  border-left: 1px solid var(--line);
}

.summary dt {
  margin-bottom: 7px;
  color: var(--muted);
  font-size: 11px;
  letter-spacing: 0.06em;
}

.summary dd {
  margin: 0;
  font-size: 15px;
  font-weight: 600;
}

.file-panel {
  position: relative;
  z-index: 2;
  padding: clamp(34px, 4vw, 56px);
  border: 1px solid rgba(24, 33, 30, 0.18);
  border-radius: 2px 2px 26px 2px;
  background:
    linear-gradient(135deg, transparent 0 72%, rgba(7, 92, 76, 0.035) 72% 100%),
    var(--paper-light);
  box-shadow: var(--shadow);
  animation: reveal-up 760ms 180ms both cubic-bezier(0.22, 1, 0.36, 1);
}

.file-panel::before {
  position: absolute;
  inset: 10px;
  z-index: -1;
  border: 1px solid rgba(24, 33, 30, 0.08);
  border-radius: 1px 1px 19px 1px;
  content: "";
  pointer-events: none;
}

.panel-rivet {
  position: absolute;
  right: 18px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--steel);
  box-shadow: inset 0 0 0 1px #88928d;
}

.panel-rivet--top {
  top: 18px;
}

.panel-rivet--bottom {
  bottom: 18px;
}

.file-passport {
  display: grid;
  grid-template-columns: 82px 1fr;
  gap: 22px;
  align-items: center;
}

.file-type {
  display: grid;
  width: 82px;
  height: 96px;
  border: 1px solid var(--line);
  background: var(--white);
  place-items: center;
}

.file-type svg {
  width: 34px;
  fill: none;
  stroke: var(--green);
  stroke-linecap: square;
  stroke-width: 2;
}

.file-type span {
  width: calc(100% + 2px);
  margin: 0 -1px -1px;
  padding: 5px 0;
  background: var(--green);
  color: var(--white);
  font-family: var(--utility);
  font-size: 9px;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-align: center;
}

.file-heading p {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: 12px;
  letter-spacing: 0.07em;
}

.file-heading h2 {
  margin: 0;
  font-size: clamp(26px, 3vw, 38px);
  font-weight: 650;
  letter-spacing: -0.035em;
}

.checksum {
  display: flex;
  grid-column: 1 / -1;
  align-items: center;
  justify-content: space-between;
  margin-top: 6px;
  padding: 11px 13px;
  border: 1px dashed var(--line);
  color: var(--muted);
  font-size: 10px;
}

.checksum code {
  color: #3d4944;
  font-family: inherit;
}

.download-button {
  position: relative;
  display: grid;
  grid-template-columns: 42px 1fr auto;
  gap: 15px;
  align-items: center;
  min-height: 86px;
  margin-top: 34px;
  padding: 14px 18px;
  overflow: hidden;
  border: 1px solid var(--red);
  border-radius: 2px;
  background: var(--red);
  color: var(--white);
  text-decoration: none;
  transition: background 200ms ease, box-shadow 200ms ease, transform 200ms ease;
}

.download-button::before {
  position: absolute;
  inset: 0;
  background: linear-gradient(105deg, transparent 0 43%, rgba(255, 255, 255, 0.14) 48%, transparent 53%);
  content: "";
  transform: translateX(-110%);
  transition: transform 560ms cubic-bezier(0.22, 1, 0.36, 1);
}

.download-button:hover {
  background: var(--red-dark);
  box-shadow: 0 15px 28px rgba(217, 47, 53, 0.24);
  transform: translateY(-2px);
}

.download-button:hover::before {
  transform: translateX(110%);
}

.download-button:focus-visible {
  outline: 3px solid rgba(217, 47, 53, 0.42);
  outline-offset: 4px;
}

.download-button.is-started {
  background: var(--ink);
  border-color: var(--ink);
}

.button-icon {
  display: grid;
  width: 42px;
  height: 42px;
  border: 1px solid rgba(255, 255, 255, 0.36);
  border-radius: 50%;
  place-items: center;
}

.button-icon svg {
  width: 20px;
  fill: none;
  stroke: currentColor;
  stroke-linecap: square;
  stroke-linejoin: miter;
  stroke-width: 1.7;
}

.button-copy {
  position: relative;
  display: grid;
  gap: 4px;
}

.button-copy strong {
  font-size: 16px;
  letter-spacing: 0.04em;
}

.button-copy small {
  color: rgba(255, 255, 255, 0.7);
  font-family: var(--utility);
  font-size: 9px;
  letter-spacing: 0.07em;
}

.button-arrow {
  position: relative;
  font-family: var(--utility);
  font-size: 22px;
}

.download-note {
  margin: 14px 0 0;
  color: var(--muted);
  font-size: 11px;
  line-height: 1.6;
  text-align: center;
}

.archive-spine {
  display: flex;
  height: min(520px, 70vh);
  flex-direction: column;
  gap: 16px;
  align-items: center;
  justify-content: center;
  border-radius: 2px;
  background: linear-gradient(var(--red) 0 24%, var(--paper-light) 24% 71%, var(--green) 71% 100%);
  box-shadow: 0 18px 42px rgba(24, 33, 30, 0.12);
  animation: reveal-up 700ms 280ms both cubic-bezier(0.22, 1, 0.36, 1);
}

.archive-spine span {
  color: var(--ink);
  font-family: var(--utility);
  font-size: 8px;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-orientation: mixed;
  writing-mode: vertical-rl;
}

.archive-spine span:first-child,
.archive-spine span:last-child {
  color: var(--white);
}

.archive-spine i {
  width: 1px;
  height: 70px;
  background: var(--line);
}

.footer {
  display: flex;
  justify-content: space-between;
  padding: 24px 0 28px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 9px;
  letter-spacing: 0.08em;
}

.footer p {
  margin: 0;
}

@keyframes reveal-up {
  from {
    opacity: 0;
    transform: translateY(18px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes status-pulse {
  0% {
    opacity: 0.8;
    transform: scale(0.6);
  }
  70%,
  100% {
    opacity: 0;
    transform: scale(1.6);
  }
}

@media (max-width: 1040px) {
  .hero {
    grid-template-columns: 1fr minmax(350px, 0.8fr);
    gap: 48px;
  }

  .archive-spine {
    display: none;
  }
}

@media (max-width: 780px) {
  .site-shell {
    width: min(100% - 34px, 620px);
  }

  .masthead {
    padding: 20px 0;
  }

  .hero {
    grid-template-columns: 1fr;
    gap: 52px;
    padding: 58px 0 64px;
  }

  .hero-copy {
    max-width: 100%;
  }

  h1 {
    font-size: clamp(50px, 14.3vw, 78px);
  }

  .summary {
    margin-top: 38px;
  }

  .file-panel {
    padding: 34px 28px;
  }
}

@media (max-width: 500px) {
  .brand-copy small,
  .release-tag {
    display: none;
  }

  .brand-mark {
    width: 35px;
    height: 35px;
  }

  .eyebrow {
    margin-bottom: 25px;
  }

  .intro {
    margin-top: 27px;
    font-size: 15px;
  }

  .summary {
    grid-template-columns: 1fr;
  }

  .summary div,
  .summary div + div {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    padding: 13px 0;
    border-bottom: 1px solid var(--line);
    border-left: 0;
  }

  .summary dt {
    margin: 0;
  }

  .file-passport {
    grid-template-columns: 65px 1fr;
    gap: 16px;
  }

  .file-type {
    width: 65px;
    height: 82px;
  }

  .checksum {
    gap: 12px;
  }

  .download-button {
    grid-template-columns: 38px 1fr;
    padding: 13px 14px;
  }

  .button-icon {
    width: 38px;
    height: 38px;
  }

  .button-arrow {
    display: none;
  }

  .footer {
    gap: 14px;
    align-items: flex-start;
    flex-direction: column;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}