:root {
  --ink: #1a2421;
  --muted: #5c6b66;
  --paper: #f0ebe1;
  --panel: #fffdf8;
  --line: #d7d0c3;
  --accent: #2f5d50;
  --accent-hover: #244a40;
  --accent-soft: rgba(47, 93, 80, 0.1);
  --focus: #c4a35a;
  --hero-deep: #1e3a32;
  --hero-mid: #2f5d50;
  --hero-glow: #3d7a68;
  --font-display: "Noto Serif SC", "Songti SC", serif;
  --font-body: "Source Sans 3", "PingFang SC", "Microsoft YaHei", sans-serif;
  --radius: 10px;
  --shadow-soft: 0 10px 28px rgba(26, 36, 33, 0.1);
  --ease: 200ms ease;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
}

body {
  font-family: var(--font-body);
  color: var(--ink);
  background:
    radial-gradient(1100px 520px at 8% -8%, #e3ece6 0%, transparent 55%),
    radial-gradient(900px 480px at 100% 0%, #ebe3d4 0%, transparent 48%),
    var(--paper);
  line-height: 1.55;
}

a,
button,
summary {
  cursor: pointer;
}

/* ——— Hero (full-bleed) ——— */

.hero {
  position: relative;
  overflow: hidden;
  color: #f7f4ec;
  background:
    radial-gradient(800px 420px at 85% 20%, rgba(61, 122, 104, 0.45), transparent 60%),
    linear-gradient(145deg, var(--hero-deep) 0%, var(--hero-mid) 55%, #3a6b5c 100%);
}

.hero::after {
  content: "";
  position: absolute;
  inset: auto -10% -40% 40%;
  height: 70%;
  background: radial-gradient(circle, rgba(196, 163, 90, 0.18), transparent 65%);
  pointer-events: none;
}

.hero-inner {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
  gap: 2.5rem 3rem;
  align-items: center;
  max-width: 1120px;
  margin: 0 auto;
  padding: 4rem 1.5rem 3.5rem;
}

.eyebrow {
  margin: 0 0 0.85rem;
  font-size: 0.82rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: rgba(247, 244, 236, 0.72);
}

.brand {
  margin: 0 0 0.9rem;
  font-family: var(--font-display);
  font-size: clamp(2.6rem, 6vw, 3.8rem);
  font-weight: 700;
  letter-spacing: 0.06em;
  line-height: 1.12;
}

.lede {
  margin: 0 0 1rem;
  max-width: 28rem;
  font-size: 1.12rem;
  color: rgba(247, 244, 236, 0.88);
}

.version-line {
  margin: 0 0 1.5rem;
  color: rgba(247, 244, 236, 0.65);
  font-size: 0.95rem;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

.hint {
  margin: 0;
  min-height: 1.4em;
  color: var(--muted);
  font-size: 0.92rem;
}

.hero .hint {
  color: rgba(247, 244, 236, 0.68);
}

.hero-visual {
  display: flex;
  justify-content: center;
  animation: float-in 700ms ease both;
}

.device {
  width: min(100%, 280px);
  border-radius: 28px;
  padding: 12px;
  background: linear-gradient(160deg, #2a2f2d, #151a18);
  box-shadow:
    0 30px 60px rgba(0, 0, 0, 0.35),
    inset 0 0 0 1px rgba(255, 255, 255, 0.08);
  animation: device-float 5s ease-in-out infinite;
}

.device-notch {
  width: 36%;
  height: 8px;
  margin: 4px auto 12px;
  border-radius: 999px;
  background: #0c0f0e;
}

.device-screen {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  min-height: 360px;
  padding: 1rem;
  border-radius: 18px;
  background:
    linear-gradient(180deg, #f7f3ea 0%, #efe8da 100%);
  color: var(--ink);
}

.preview-bar {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.25rem;
}

.preview-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
}

.preview-title {
  font-family: var(--font-display);
  font-size: 0.95rem;
  font-weight: 500;
}

.preview-card {
  display: grid;
  gap: 0.15rem;
  padding: 0.75rem 0.85rem;
  border-radius: 8px;
  background: rgba(255, 253, 248, 0.92);
  border: 1px solid rgba(215, 208, 195, 0.9);
  box-shadow: 0 4px 12px rgba(26, 36, 33, 0.05);
  transition: transform var(--ease);
}

.preview-card.is-muted {
  opacity: 0.78;
}

.preview-label {
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  color: var(--accent);
  text-transform: uppercase;
}

.preview-name {
  font-size: 0.95rem;
  font-weight: 600;
}

.preview-meta {
  font-size: 0.8rem;
  color: var(--muted);
}

@keyframes float-in {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes device-float {
  0%,
  100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-10px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .hero-visual,
  .device,
  .card,
  .feature,
  .btn {
    animation: none !important;
    transition: none !important;
  }
}

/* ——— Page body ——— */

.page {
  max-width: 1120px;
  margin: 0 auto;
  padding: 2.75rem 1.5rem 4rem;
}

.section-head {
  margin-bottom: 1.5rem;
}

.section-lede {
  margin: 0.4rem 0 0;
  max-width: 36rem;
  color: var(--muted);
  font-size: 0.98rem;
}

.platforms,
.features,
.feedback {
  padding: 2.25rem 0;
  border-bottom: 1px solid var(--line);
}

h2 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.55rem;
  font-weight: 500;
}

.platform-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1rem;
}

.card {
  display: flex;
  flex-direction: column;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.35rem 1.2rem 1.4rem;
  transition: transform var(--ease), box-shadow var(--ease), border-color var(--ease);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-soft);
  border-color: rgba(47, 93, 80, 0.35);
}

.card-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  margin-bottom: 0.85rem;
  border-radius: 8px;
  background: var(--accent-soft);
  color: var(--accent);
}

.card-icon svg {
  width: 1.25rem;
  height: 1.25rem;
}

.card h3 {
  margin: 0 0 0.35rem;
  font-size: 1.1rem;
}

.card p {
  margin: 0 0 1rem;
  color: var(--muted);
  font-size: 0.92rem;
  flex: 1;
}

.card .btn,
.card .btn-stack {
  margin-top: auto;
}

.btn-stack {
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.75rem;
  padding: 0.55rem 1.15rem;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid transparent;
  transition: background var(--ease), transform var(--ease), box-shadow var(--ease);
}

.btn:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 6px 16px rgba(36, 74, 64, 0.28);
}

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

.hero .btn {
  background: #f7f4ec;
  color: var(--hero-deep);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.18);
}

.hero .btn:hover {
  background: #fff;
  box-shadow: 0 10px 24px rgba(0, 0, 0, 0.22);
}

.hero .btn-secondary {
  background: transparent;
  color: #f7f4ec;
  border-color: rgba(247, 244, 236, 0.55);
  box-shadow: none;
}

.hero .btn-secondary:hover {
  background: rgba(247, 244, 236, 0.12);
  box-shadow: none;
}

.btn-secondary {
  background: transparent;
  color: var(--accent);
  border-color: var(--accent);
}

.btn-secondary:hover {
  background: var(--accent-soft);
  box-shadow: none;
}

.btn.is-disabled,
.btn[aria-disabled="true"] {
  opacity: 0.45;
  pointer-events: none;
}

.fine {
  margin: 0.65rem 0 0;
  font-size: 0.82rem;
  color: var(--muted);
  word-break: break-all;
}

.note {
  margin: 1.25rem 0 0;
  color: var(--muted);
  font-size: 0.88rem;
}

.install-help {
  margin-top: 1.5rem;
  padding: 1.15rem 1.25rem 1.25rem;
  border-radius: var(--radius);
  border: 1px solid rgba(47, 93, 80, 0.28);
  background: rgba(47, 93, 80, 0.06);
}

.install-help h3 {
  margin: 0 0 0.55rem;
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 500;
}

.install-help p {
  margin: 0 0 0.75rem;
  color: var(--muted);
  font-size: 0.95rem;
}

.install-help ol {
  margin: 0 0 0.75rem;
  padding-left: 1.25rem;
  color: var(--ink);
  font-size: 0.95rem;
}

.install-help li {
  margin-bottom: 0.35rem;
}

.install-help .fine {
  margin: 0;
}

.card.is-recommended {
  border-color: var(--accent);
  box-shadow:
    inset 0 0 0 1px var(--accent),
    var(--shadow-soft);
}

.card.is-recommended::before {
  content: "当前设备";
  display: inline-block;
  align-self: flex-start;
  margin-bottom: 0.65rem;
  padding: 0.15rem 0.55rem;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.04em;
}

.feature-list {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1.25rem;
  margin-bottom: 1.75rem;
}

.feature {
  padding: 0.25rem 0;
  transition: transform var(--ease);
}

.feature:hover {
  transform: translateY(-2px);
}

.feature-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.4rem;
  height: 2.4rem;
  margin-bottom: 0.75rem;
  border-radius: 8px;
  color: var(--accent);
  background: var(--accent-soft);
}

.feature-icon svg {
  width: 1.2rem;
  height: 1.2rem;
}

.feature h3 {
  margin: 0 0 0.35rem;
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 500;
}

.feature p {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.disclaimer {
  margin: 0;
  padding: 0.9rem 1rem;
  border-left: 3px solid var(--accent);
  color: var(--muted);
  font-size: 0.9rem;
  background: rgba(255, 253, 248, 0.7);
  border-radius: 0 8px 8px 0;
}

.feedback-panel {
  max-width: 36rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255, 253, 248, 0.55);
  padding: 0.25rem 1rem 0.25rem;
}

.feedback-panel summary {
  list-style: none;
  padding: 0.95rem 0;
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 500;
  color: var(--ink);
}

.feedback-panel summary::-webkit-details-marker {
  display: none;
}

.feedback-panel summary::after {
  content: "+";
  float: right;
  color: var(--muted);
  font-weight: 400;
  font-family: var(--font-body);
}

.feedback-panel[open] summary::after {
  content: "−";
}

.feedback-panel[open] {
  padding-bottom: 1.15rem;
}

.feedback-lede {
  margin: 0 0 1.25rem;
  color: var(--muted);
  font-size: 0.95rem;
}

.feedback-form {
  display: flex;
  flex-direction: column;
  gap: 1.15rem;
}

.audience {
  margin: 0;
  padding: 0;
  border: none;
}

.audience legend {
  margin-bottom: 0.65rem;
  font-weight: 600;
  font-size: 0.95rem;
}

.audience label {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  margin-bottom: 0.4rem;
  color: var(--ink);
  font-size: 0.95rem;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  font-size: 0.95rem;
  font-weight: 600;
}

.field textarea,
.field input {
  font: inherit;
  font-weight: 400;
  color: var(--ink);
  padding: 0.65rem 0.75rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  resize: vertical;
}

.field textarea:focus-visible,
.field input:focus-visible,
.audience input:focus-visible,
.feedback-panel summary:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

.feedback-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem 1rem;
}

.feedback-actions .btn {
  border: none;
}

.feedback-actions .hint {
  flex: 1;
  min-width: 12rem;
  color: var(--muted);
}

.footer {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 1.5rem;
  padding-top: 1.75rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.footer a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--ease);
}

.footer a:hover {
  color: var(--accent-hover);
  text-decoration: underline;
}

@media (max-width: 960px) {
  .platform-grid,
  .feature-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 720px) {
  .hero-inner {
    grid-template-columns: 1fr;
    padding: 2.75rem 1.25rem 2.5rem;
    gap: 2rem;
    text-align: center;
  }

  .lede {
    margin-left: auto;
    margin-right: auto;
  }

  .cta-row {
    justify-content: center;
  }

  .hero-visual {
    order: -1;
  }

  .device {
    width: min(100%, 220px);
    animation: none;
  }

  .device-screen {
    min-height: 280px;
  }

  .page {
    padding: 2rem 1.25rem 3rem;
  }

  .platform-grid,
  .feature-list {
    grid-template-columns: 1fr;
  }

  .card.is-recommended::before {
    align-self: center;
  }

  .card {
    text-align: center;
  }

  .card-icon {
    margin-left: auto;
    margin-right: auto;
  }

  .feature {
    text-align: left;
  }
}