:root {
  /* 正文：素问浅色 */
  --ink: #1a1a1a;
  --muted: #64748b;
  --paper: #f5f5f7;
  --panel: #ffffff;
  --line: #e2e8f0;
  --accent: #3a5670;
  --accent-hover: #2d4459;
  --accent-soft: rgba(58, 86, 112, 0.1);
  --focus: #5d7a9c;
  /* Hero：深青灰（素问强调色加深） */
  --hero-deep: #1c2a38;
  --hero-mid: #243447;
  --hero-lift: #2c4054;
  --hero-mist: #f4f6f8;
  --font-display: "Noto Serif SC", "Songti SC", serif;
  --font-body: "Source Sans 3", "PingFang SC", "Microsoft YaHei", sans-serif;
  --radius: 10px;
  --radius-input: 9px;
  --shadow-soft: 0 8px 24px rgba(26, 26, 26, 0.08);
  --ease: 200ms ease;
}

* {
  box-sizing: border-box;
}

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

body {
  font-family: var(--font-body);
  color: var(--ink);
  background:
    linear-gradient(180deg, #ffffff 0%, #f8f8f8 42%, var(--paper) 100%);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

a,
button,
summary {
  cursor: pointer;
}

/* ——— Hero：干净深青灰 ——— */

.hero {
  position: relative;
  overflow: hidden;
  color: var(--hero-mist);
  background: linear-gradient(
    165deg,
    var(--hero-lift) 0%,
    var(--hero-mid) 48%,
    var(--hero-deep) 100%
  );
  border-bottom: 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: 0.14em;
  text-transform: uppercase;
  color: rgba(244, 246, 248, 0.58);
}

.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;
  color: #ffffff;
}

.lede {
  margin: 0 0 1rem;
  max-width: 28rem;
  font-size: 1.12rem;
  color: rgba(244, 246, 248, 0.78);
}

.version-line {
  margin: 0 0 1.5rem;
  color: rgba(244, 246, 248, 0.58);
  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(244, 246, 248, 0.62);
}

.hero .btn {
  background: #ffffff;
  color: #243447;
  border-color: transparent;
}

.hero .btn:hover {
  background: #eef2f6;
  color: #1c2a38;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.22);
}

.hero .btn-secondary {
  background: transparent;
  color: #ffffff;
  border-color: rgba(255, 255, 255, 0.45);
  box-shadow: none;
}

.hero .btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  color: #ffffff;
  border-color: rgba(255, 255, 255, 0.7);
  box-shadow: none;
}

.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, #3a3f45, #1c1f24);
  box-shadow:
    0 28px 56px rgba(0, 0, 0, 0.32),
    inset 0 0 0 1px rgba(255, 255, 255, 0.1);
  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, #ffffff 0%, #f8f8f8 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: 700;
}

.preview-card {
  display: grid;
  gap: 0.15rem;
  padding: 0.75rem 0.85rem;
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.95);
  border: 1px solid var(--line);
  box-shadow: 0 4px 12px rgba(26, 26, 26, 0.04);
}

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

.preview-label {
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  color: var(--accent);
  text-transform: uppercase;
  font-weight: 700;
}

.preview-name {
  font-size: 0.95rem;
  font-weight: 700;
}

.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);
  }
}

@keyframes device-float-mobile {
  0%,
  100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-6px);
  }
}

@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);
}

.page > .feedback:first-child {
  padding-top: 0.35rem;
}

h2 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.55rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.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(58, 86, 112, 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;
  font-weight: 700;
}

.card-desc {
  margin: 0 0 1rem;
  color: var(--muted);
  font-size: 0.92rem;
  flex: 1;
  line-height: 1.45;
}

.card-actions {
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  gap: 0.55rem;
  margin-top: auto;
}

.card-actions .btn {
  width: 100%;
  box-sizing: border-box;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.75rem;
  padding: 0.55rem 1.15rem;
  border-radius: 9px;
  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(58, 86, 112, 0.22);
}

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

.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;
  font-size: 0.82rem;
  color: var(--muted);
  word-break: break-all;
  line-height: 1.35;
}

.fine:empty {
  display: none;
}

.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;
}

.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: 700;
}

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

.feature .coming {
  margin-top: 0.45rem;
  color: var(--accent);
  font-size: 0.85rem;
  letter-spacing: 0.02em;
}

.win-dialog {
  width: min(100% - 2rem, 28rem);
  margin: auto;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  color: var(--ink);
  box-shadow: 0 24px 48px rgba(26, 26, 26, 0.18);
}

.win-dialog::backdrop {
  background: rgba(26, 26, 26, 0.38);
}

.win-dialog-inner {
  margin: 0;
  padding: 1.35rem 1.4rem 1.25rem;
}

.win-dialog h3 {
  margin: 0 0 0.75rem;
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
}

.win-dialog p {
  margin: 0 0 0.85rem;
  color: var(--muted);
  font-size: 0.95rem;
}

.win-dialog ol {
  margin: 0 0 0.85rem;
  padding-left: 1.2rem;
  color: var(--ink);
  font-size: 0.95rem;
}

.win-dialog li + li {
  margin-top: 0.35rem;
}

.win-dialog .fine {
  margin: 0 0 1.1rem;
}

.win-dialog-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.65rem;
}

.feedback-panel {
  max-width: 36rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.7);
  padding: 0.25rem 1rem 0.25rem;
  transition: border-color var(--ease), background var(--ease);
}

.feedback-panel.is-done {
  border-color: rgba(58, 86, 112, 0.28);
  background: rgba(58, 86, 112, 0.04);
}

.feedback-panel.is-success summary,
.feedback-panel.is-closing summary {
  pointer-events: none;
}

.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);
  transition: color var(--ease);
}

.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);
  transition: transform 220ms ease, opacity 220ms ease;
}

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

.feedback-panel.is-done summary::after {
  content: "✓";
  color: var(--accent);
}

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

.feedback-collapse {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows 380ms ease;
}

.feedback-panel[open] .feedback-collapse {
  grid-template-rows: 1fr;
}

.feedback-panel.is-closing .feedback-collapse {
  grid-template-rows: 0fr;
}

.feedback-collapse-inner {
  overflow: hidden;
  min-height: 0;
  /* 给输入框 focus outline（offset 2px）留出左右空间，避免像被裁断 */
  padding-inline: 4px;
}

.feedback-live,
.feedback-thanks {
  transition: opacity 280ms ease, transform 280ms ease;
}

.feedback-panel.is-success .feedback-live {
  display: none;
}

.feedback-thanks {
  display: none;
  padding: 0.35rem 0 0.5rem;
}

.feedback-panel.is-success .feedback-thanks {
  display: block;
  animation: feedback-thanks-in 320ms ease both;
}

.feedback-thanks-title {
  margin: 0 0 0.35rem;
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--accent);
}

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

@keyframes feedback-thanks-in {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (prefers-reduced-motion: reduce) {
  .feedback-collapse,
  .feedback-live,
  .feedback-thanks,
  .feedback-panel summary::after {
    transition: none !important;
    animation: none !important;
  }
}

.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: var(--radius-input);
  background: var(--panel);
  resize: vertical;
}

.field textarea:focus-visible,
.field input:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: -2px; /* 画在框内，不被收起容器的 overflow 裁切 */
}

.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;
}

/* ——— 文档页（隐私等） ——— */

.doc-body {
  background:
    linear-gradient(180deg, #ffffff 0%, #f8f8f8 42%, var(--paper) 100%);
}

.doc-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  max-width: 42rem;
  margin: 0 auto;
  padding: 1.25rem 1.25rem 0;
}

.doc-brand {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--accent);
  text-decoration: none;
  letter-spacing: 0.06em;
}

.doc-back {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.92rem;
}

.doc-back:hover {
  color: var(--accent);
  text-decoration: underline;
}

.doc-main {
  max-width: 42rem;
  margin: 0 auto;
  padding: 1.5rem 1.25rem 2.5rem;
}

.doc-main h1 {
  margin: 0 0 0.5rem;
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 5vw, 2.15rem);
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--ink);
}

.doc-meta {
  margin: 0 0 1.5rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.doc-main h2 {
  margin: 1.75rem 0 0.65rem;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--ink);
}

.doc-main p,
.doc-main li {
  color: #334155;
  font-size: 0.98rem;
  line-height: 1.65;
}

.doc-main ul {
  margin: 0.5rem 0 0;
  padding-left: 1.25rem;
}

.doc-main li {
  margin-bottom: 0.45rem;
}

.doc-main a {
  color: var(--accent);
}

.doc-footer {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 1.5rem;
  max-width: 42rem;
  margin: 0 auto;
  padding: 0 1.25rem 2.5rem;
  color: var(--muted);
  font-size: 0.9rem;
}

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

.doc-footer a: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;
    /* 品牌 → CTA → 示意机；首屏紧凑 */
    padding: 2.1rem 1.25rem 1.75rem;
    gap: 1.35rem;
    text-align: center;
    justify-items: center;
  }

  .hero-copy {
    width: 100%;
    max-width: 26rem;
    animation: float-in 520ms ease both;
  }

  .eyebrow {
    margin-bottom: 0.55rem;
    font-size: 0.75rem;
    letter-spacing: 0.16em;
  }

  .brand {
    margin-bottom: 0.55rem;
    font-size: clamp(2.15rem, 9.5vw, 2.75rem);
    letter-spacing: 0.08em;
  }

  .lede {
    margin: 0 auto 0.65rem;
    max-width: 22rem;
    font-size: 1rem;
    line-height: 1.5;
  }

  .version-line {
    margin-bottom: 1.1rem;
    font-size: 0.88rem;
  }

  .cta-row {
    justify-content: center;
    margin-bottom: 0.45rem;
  }

  .cta-row .btn {
    min-width: min(100%, 16rem);
    justify-content: center;
  }

  .hero .hint {
    font-size: 0.85rem;
  }

  /* 示意机在 CTA 下：可辨认，但不抢品牌 */
  .hero-visual {
    width: 100%;
    margin-top: 0.55rem;
    opacity: 1;
    animation: float-in 700ms ease 80ms both;
  }

  .device {
    width: min(52vw, 210px);
    padding: 10px;
    border-radius: 22px;
    animation: device-float-mobile 4.5s ease-in-out infinite;
    box-shadow:
      0 18px 36px rgba(0, 0, 0, 0.3),
      inset 0 0 0 1px rgba(255, 255, 255, 0.1);
  }

  .device-notch {
    height: 7px;
    margin: 3px auto 10px;
  }

  .device-screen {
    gap: 0.5rem;
    min-height: 0;
    padding: 0.75rem 0.8rem 0.85rem;
    border-radius: 15px;
  }

  .preview-bar {
    margin-bottom: 0.15rem;
  }

  .preview-title {
    font-size: 0.85rem;
  }

  .preview-card {
    padding: 0.55rem 0.65rem;
    border-radius: 9px;
  }

  .preview-card.is-muted {
    display: grid;
    opacity: 0.72;
  }

  .preview-label {
    font-size: 0.66rem;
  }

  .preview-name {
    font-size: 0.84rem;
  }

  .preview-meta {
    font-size: 0.72rem;
  }

  .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;
  }
}

/* 手机横屏：略像桌面，左文右机 */
@media (max-width: 720px) and (orientation: landscape) {
  .hero-inner {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    text-align: left;
    justify-items: stretch;
    align-items: center;
    padding: 1.35rem 1.25rem 1.25rem;
    gap: 1.25rem 1.5rem;
  }

  .hero-copy {
    max-width: none;
    animation: none;
  }

  .lede {
    margin-left: 0;
    margin-right: 0;
  }

  .cta-row {
    justify-content: flex-start;
  }

  .cta-row .btn {
    min-width: 0;
  }

  .brand {
    font-size: clamp(1.85rem, 5.5vw, 2.4rem);
  }

  .hero-visual {
    margin-top: 0;
  }

  .device {
    width: min(28vw, 150px);
  }

  .preview-card.is-muted {
    display: grid;
  }
}