:root {
  color-scheme: light;
  --bg: #f7f8fb;
  --surface: #ffffff;
  --ink: #111827;
  --muted: #5f6b7a;
  --line: #dbe2ea;
  --accent: #2563eb;
  --accent-dark: #1d4ed8;
  --accent-soft: #eaf1ff;
  --shadow: 0 24px 70px rgba(15, 23, 42, 0.12);
  font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.6;
}

body.modal-open {
  overflow: hidden;
}

a {
  color: inherit;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 18px clamp(20px, 5vw, 64px);
  background: rgba(247, 248, 251, 0.88);
  border-bottom: 1px solid rgba(219, 226, 234, 0.85);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-weight: 760;
  text-decoration: none;
  letter-spacing: 0;
}

.brand img {
  border-radius: 12px;
}

.nav,
.site-footer nav {
  display: flex;
  align-items: center;
  gap: 18px;
  color: var(--muted);
  font-size: 14px;
}

.nav a,
.site-footer a {
  text-decoration: none;
}

.lang-switch {
  display: inline-grid;
  grid-template-columns: 1fr 1fr;
  gap: 2px;
  padding: 3px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #ffffff;
}

.lang-switch button {
  min-width: 48px;
  min-height: 32px;
  border: 0;
  border-radius: 999px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font: inherit;
  font-size: 13px;
  font-weight: 720;
}

html[data-site-lang="en"] [data-lang-option="en"],
html[data-site-lang="zh"] [data-lang-option="zh"] {
  background: var(--ink);
  color: #ffffff;
}

.lang-zh,
[data-lang-block="zh"] {
  display: none;
}

html[data-site-lang="zh"] .lang-en,
html[data-site-lang="zh"] [data-lang-block="en"] {
  display: none;
}

html[data-site-lang="zh"] .lang-zh {
  display: inline;
}

html[data-site-lang="zh"] [data-lang-block="zh"] {
  display: block;
}

.nav a:hover,
.site-footer a:hover,
.text-link:hover {
  color: var(--accent);
}

.hero,
.section,
.site-footer {
  width: min(1160px, calc(100% - 40px));
  margin: 0 auto;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(360px, 1.2fr);
  gap: clamp(28px, 5vw, 72px);
  align-items: center;
  padding: 72px 0 52px;
}

.hero-copy {
  min-width: 0;
}

.eyebrow {
  margin: 0 0 14px;
  color: var(--accent);
  font-size: 13px;
  font-weight: 760;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 760px;
  margin-bottom: 22px;
  font-size: clamp(42px, 7vw, 76px);
  line-height: 0.98;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 16px;
  font-size: clamp(30px, 4.6vw, 52px);
  line-height: 1.05;
  letter-spacing: 0;
}

h3 {
  margin-bottom: 10px;
  font-size: 20px;
  line-height: 1.2;
}

.hero-text {
  max-width: 640px;
  color: var(--muted);
  font-size: 19px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 30px 0 22px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 12px 18px;
  border-radius: 12px;
  border: 1px solid transparent;
  font-weight: 720;
  text-decoration: none;
  transition: transform 160ms ease, background 160ms ease, border-color 160ms ease;
}

.button:hover {
  transform: translateY(-1px);
}

.button:active {
  transform: translateY(0);
}

.button.primary {
  background: var(--accent);
  color: #ffffff;
  box-shadow: 0 14px 32px rgba(37, 99, 235, 0.22);
}

.button.primary:hover {
  background: var(--accent-dark);
}

.button.secondary {
  background: var(--surface);
  color: var(--ink);
  border-color: var(--line);
}

.trust-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.trust-list li {
  padding: 7px 10px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #ffffff;
  color: var(--muted);
  font-size: 13px;
  font-weight: 650;
}

.hero-media {
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: 22px;
  background: #ffffff;
  box-shadow: var(--shadow);
}

.hero-media img,
.split img {
  border-radius: 16px;
  border: 1px solid #e5eaf1;
}

.section {
  padding: 72px 0;
}

.problem,
.privacy {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(320px, 1fr);
  gap: clamp(24px, 5vw, 72px);
  align-items: start;
  border-top: 1px solid var(--line);
}

.support {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(320px, 1fr);
  gap: clamp(24px, 5vw, 72px);
  align-items: start;
  border-top: 1px solid var(--line);
}

.support p {
  color: var(--muted);
  font-size: 18px;
}

.support-panel {
  padding: 28px;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: var(--surface);
}

.support-panel p {
  margin-bottom: 0;
}

.qr-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px;
  align-items: start;
}

.qr-card {
  display: grid;
  grid-template-rows: 1fr auto;
  gap: 14px;
  justify-items: center;
  text-align: center;
  min-width: 0;
}

.qr-card strong {
  color: var(--ink);
  font-size: 18px;
  line-height: 1.2;
}

.qr-frame {
  display: grid;
  width: min(100%, 230px);
  height: 326px;
  place-items: center;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: #f8fafc;
}

.qr-placeholder {
  display: grid;
  width: 148px;
  height: 148px;
  place-items: center;
  padding: 16px;
  border: 1px dashed #9aa8b7;
  border-radius: 14px;
  background:
    linear-gradient(45deg, rgba(37, 99, 235, 0.07) 25%, transparent 25%),
    linear-gradient(-45deg, rgba(37, 99, 235, 0.07) 25%, transparent 25%),
    #f8fafc;
  color: var(--muted);
  font-size: 13px;
  font-weight: 720;
  line-height: 1.45;
}

.qr-image {
  width: 100%;
  max-height: 298px;
  object-fit: contain;
  border-radius: 12px;
  background: transparent;
}

.problem p,
.privacy-points,
.note p,
.final-cta p {
  color: var(--muted);
  font-size: 18px;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1px;
  padding: 1px;
  border-radius: 18px;
  background: var(--line);
  overflow: hidden;
}

.feature-grid article {
  min-height: 260px;
  padding: 28px;
  background: var(--surface);
}

.feature-number {
  display: block;
  margin-bottom: 46px;
  color: var(--accent);
  font-size: 13px;
  font-weight: 760;
}

.feature-grid p {
  color: var(--muted);
}

.split {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(360px, 1.15fr);
  gap: clamp(24px, 5vw, 64px);
  align-items: center;
  border-top: 1px solid var(--line);
}

.split.reverse {
  grid-template-columns: minmax(360px, 1.15fr) minmax(0, 0.9fr);
}

.split.reverse div {
  order: 2;
}

.split.reverse img {
  order: 1;
}

.split p {
  color: var(--muted);
  font-size: 18px;
}

.note {
  padding: 40px;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: var(--surface);
}

.note h2 {
  font-size: clamp(28px, 3vw, 40px);
}

code {
  padding: 2px 6px;
  border-radius: 6px;
  background: var(--accent-soft);
  color: var(--accent-dark);
  font-size: 0.92em;
}

.text-link {
  display: inline-flex;
  margin-top: 4px;
  color: var(--accent);
  font-weight: 720;
  text-decoration: none;
}

.final-cta {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 8px;
  padding: 56px;
  border-radius: 24px;
  background: #111827;
  color: #ffffff;
}

.final-cta h2 {
  max-width: 820px;
}

.final-cta p {
  max-width: 680px;
  color: #cbd5e1;
}

.final-cta .button.primary {
  margin-top: 14px;
  background: #ffffff;
  color: #111827;
  box-shadow: none;
}

.site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 38px 0 48px;
  color: var(--muted);
  font-size: 14px;
}

.policy-page {
  width: min(860px, calc(100% - 40px));
  margin: 0 auto;
  padding: 64px 0 84px;
}

.policy-page h1 {
  font-size: clamp(38px, 6vw, 64px);
}

.policy-page h2 {
  margin-top: 36px;
  font-size: 26px;
}

.policy-page p,
.policy-page li {
  color: var(--muted);
  font-size: 17px;
}

.policy-page a {
  color: var(--accent);
}

.feedback-form,
.admin-login,
.admin-toolbar,
.feedback-item {
  display: grid;
  gap: 16px;
  padding: 26px;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: var(--surface);
}

.feedback-form label,
.admin-login label,
.admin-toolbar label,
.feedback-controls label {
  display: grid;
  gap: 8px;
  color: var(--ink);
  font-weight: 720;
}

.feedback-form input,
.feedback-form textarea,
.admin-login input,
.admin-toolbar input,
.admin-toolbar select,
.feedback-controls select,
.feedback-controls textarea {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #ffffff;
  color: var(--ink);
  font: inherit;
  padding: 12px 14px;
}

.feedback-form textarea,
.feedback-controls textarea {
  resize: vertical;
}

.form-hint,
.form-status {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.form-status.success {
  color: #047857;
}

.form-status.error {
  color: #b91c1c;
}

.admin-page {
  width: min(1120px, calc(100% - 40px));
  margin: 0 auto;
  padding: 64px 0 84px;
}

.admin-page h1 {
  font-size: clamp(38px, 6vw, 64px);
}

.admin-toolbar {
  grid-template-columns: minmax(240px, 1fr) minmax(180px, 0.5fr) auto;
  align-items: end;
  margin: 26px 0;
}

.feedback-list {
  display: grid;
  gap: 16px;
}

.feedback-item-head {
  display: flex;
  justify-content: space-between;
  gap: 18px;
}

.feedback-item-head p,
.feedback-message {
  margin: 0;
  color: var(--muted);
}

.status-pill {
  align-self: flex-start;
  padding: 6px 10px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent-dark);
  font-size: 12px;
  font-weight: 760;
}

.admin-images {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.admin-image-button {
  padding: 0;
  border: 0;
  background: transparent;
  cursor: pointer;
}

.admin-image-button img {
  width: 112px;
  height: 112px;
  object-fit: cover;
  border: 1px solid var(--line);
  border-radius: 12px;
}

.feedback-controls {
  display: grid;
  grid-template-columns: 160px 160px minmax(260px, 1fr) auto;
  gap: 12px;
  align-items: end;
}

.empty-state {
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface);
  color: var(--muted);
}

.modal-layer[hidden],
.site-modal[hidden] {
  display: none;
}

.modal-layer {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: grid;
  place-items: center;
  padding: 24px;
}

.modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(15, 23, 42, 0.52);
  backdrop-filter: blur(8px);
}

.site-modal {
  position: relative;
  display: grid;
  gap: 18px;
  width: min(720px, 100%);
  max-height: min(86vh, 820px);
  padding: 26px;
  overflow: hidden;
  border: 1px solid rgba(219, 226, 234, 0.9);
  border-radius: 22px;
  background: var(--surface);
  box-shadow: 0 30px 90px rgba(15, 23, 42, 0.28);
}

.policy-modal {
  width: min(820px, 100%);
}

.modal-head {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  align-items: flex-start;
}

.modal-head h2 {
  margin-bottom: 0;
  font-size: clamp(28px, 4vw, 40px);
}

.modal-close {
  display: inline-grid;
  flex: 0 0 auto;
  width: 38px;
  height: 38px;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #ffffff;
  color: var(--ink);
  cursor: pointer;
  font: inherit;
  font-size: 24px;
  line-height: 1;
}

.modal-close:hover {
  border-color: #c7d2df;
  background: #f8fafc;
}

.modal-intro {
  margin: 0;
  color: var(--muted);
}

.modal-form {
  padding: 0;
  border: 0;
  border-radius: 0;
}

.modal-scroll {
  overflow: auto;
  padding-right: 10px;
}

.modal-scroll h3 {
  margin-top: 24px;
  margin-bottom: 8px;
  font-size: 18px;
}

.modal-scroll p {
  color: var(--muted);
}

@media (max-width: 920px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
  }

  .nav {
    flex-wrap: wrap;
  }

  .hero,
  .problem,
  .privacy,
  .support,
  .split,
  .split.reverse {
    grid-template-columns: 1fr;
  }

  .split.reverse div,
  .split.reverse img {
    order: initial;
  }

  .feature-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .qr-grid {
    grid-template-columns: repeat(2, minmax(180px, 1fr));
  }
}

@media (max-width: 620px) {
  .hero,
  .section,
  .site-footer,
  .policy-page {
    width: min(100% - 28px, 1160px);
  }

  .hero {
    padding-top: 42px;
  }

  h1 {
    font-size: 42px;
  }

  .button {
    width: 100%;
  }

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

  .feature-grid article {
    min-height: 210px;
  }

  .final-cta,
  .note {
    padding: 28px;
  }

  .site-footer {
    align-items: flex-start;
    flex-direction: column;
  }

  .lang-switch {
    width: 100%;
  }

  .site-footer nav {
    flex-wrap: wrap;
  }

  .admin-toolbar,
  .feedback-controls {
    grid-template-columns: 1fr;
  }

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

  .qr-frame {
    width: min(100%, 260px);
  }

  .modal-layer {
    align-items: end;
    padding: 12px;
  }

  .site-modal {
    max-height: 92vh;
    padding: 20px;
    border-radius: 18px;
  }

  .modal-head {
    gap: 12px;
  }
}