:root {
  --ink: #111318;
  --muted: #6d717b;
  --soft: #9aa0ad;
  --line: #e8eaf0;
  --paper: #f7f8fb;
  --blue: #243cc9;
  --blue-soft: #eef2ff;
  --teal: #0d9488;
  --amber: #c77700;
  --red: #c4362e;
  --radius: 8px;
  --max: 1360px;
  --page-gutter: clamp(48px, 5vw, 88px);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: #fff;
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI",
    "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  line-height: 1.45;
}

.mobile-blocker {
  display: none;
}

a {
  color: inherit;
  text-decoration: none;
}

.site-header {
  width: min(var(--max), calc(100% - (var(--page-gutter) * 2)));
  margin: 0 auto;
  padding: 30px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 16px;
  font-weight: 800;
  color: var(--blue);
  letter-spacing: 0;
}

.brand-mark {
  width: 18px;
  height: 18px;
  display: inline-block;
  border: 2px solid var(--blue);
  border-left-width: 6px;
  background:
    linear-gradient(var(--blue), var(--blue)) 4px 4px / 8px 2px no-repeat,
    linear-gradient(var(--blue), var(--blue)) 4px 9px / 8px 2px no-repeat;
}

nav {
  display: flex;
  align-items: center;
  justify-content: space-evenly;
  gap: 42px;
  flex: 1;
  color: #252934;
  font-size: 16px;
  font-weight: 750;
}

nav a:hover,
.login-link:hover {
  color: var(--blue);
}

.login-link {
  padding: 9px 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  font-size: 15px;
  font-weight: 700;
  background: #fff;
  box-shadow: 0 8px 24px rgba(18, 25, 38, 0.07);
}

.site-header > .login-link {
  margin-left: auto;
}

.status-pill {
  padding: 9px 14px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--muted);
  background: #fff;
  font-size: 12px;
  font-weight: 850;
}

.status-pill.online {
  color: #087568;
  border-color: rgba(13, 148, 136, 0.28);
  background: rgba(13, 148, 136, 0.08);
}

.status-pill.fallback {
  color: #9a6200;
  border-color: rgba(199, 119, 0, 0.28);
  background: rgba(199, 119, 0, 0.08);
}

.hero {
  width: min(var(--max), calc(100% - (var(--page-gutter) * 2)));
  margin: 18px auto 0;
  padding: 18px 0 22px;
  background-image:
    linear-gradient(rgba(36, 60, 201, 0.08) 1px, transparent 1px),
    linear-gradient(90deg, rgba(36, 60, 201, 0.08) 1px, transparent 1px);
  background-size: 16px 16px;
  background-position: -1px -1px;
}

.hero-copy {
  max-width: 690px;
}

.eyebrow {
  margin: 0 0 14px;
  color: var(--blue);
  font-size: 11px;
  font-weight: 900;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  letter-spacing: 0;
}

h1 {
  max-width: 650px;
  margin: 0;
  font-size: clamp(42px, 5.1vw, 64px);
  line-height: 0.94;
  font-weight: 900;
}

.title-en,
.title-cn {
  display: block;
}

.lead {
  max-width: 610px;
  margin: 16px 0 0;
  color: #767982;
  font-size: clamp(19px, 2.1vw, 24px);
  line-height: 1.05;
  font-weight: 650;
}

.metrics {
  margin-top: 26px;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  display: grid;
  grid-template-columns: repeat(4, 1fr);
}

.metrics div {
  padding: 16px 26px 14px 0;
}

.metrics strong {
  display: block;
  font-size: clamp(30px, 4vw, 42px);
  line-height: 1;
  font-weight: 850;
}

.metrics span {
  display: block;
  margin-top: 8px;
  color: var(--muted);
  font-size: 12px;
}

.hero-note {
  max-width: 520px;
  margin: 16px 0 0;
  color: #343844;
  font-size: 15px;
}

.image-strip {
  width: min(var(--max), calc(100% - (var(--page-gutter) * 2)));
  margin-left: auto;
  margin-right: auto;
  margin-top: 18px;
  display: grid;
  grid-template-columns: 0.72fr 1.65fr 1.25fr;
  gap: 14px;
  overflow: hidden;
}

.image-strip img {
  width: 100%;
  height: 260px;
  object-fit: cover;
  filter: saturate(0.9) contrast(1.02);
}

.content-grid,
.calculator-section,
.methods-note {
  width: min(var(--max), calc(100% - (var(--page-gutter) * 2)));
  margin: 104px auto 0;
}

.content-grid {
  display: grid;
  grid-template-columns: 1.1fr 1fr 1fr;
  gap: 56px 42px;
}

.section-title {
  grid-row: span 2;
}

h2 {
  margin: 0;
  font-size: clamp(34px, 4vw, 52px);
  line-height: 1.02;
  font-weight: 850;
}

h3 {
  margin: 0 0 14px;
  font-size: 24px;
  line-height: 1.1;
}

article p,
.calculator-intro p,
.methods-note p,
.panel-note {
  margin: 0;
  color: #333845;
  font-size: 15px;
}

.shap-card {
  margin-top: 24px;
  padding: 26px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  box-shadow: 0 18px 50px rgba(18, 25, 38, 0.06);
}

.shap-card h3 {
  margin-bottom: 10px;
}

.shap-card p:not(.eyebrow) {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.shap-plot {
  margin-top: 24px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.native-shap-figure {
  margin: 0;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
}

.native-shap-figure img {
  width: 100%;
  display: block;
  border-radius: 6px;
}

.native-shap-figure figcaption {
  margin-top: 10px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 800;
}

.calculator-section {
  padding: 72px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.calculator-page-hero {
  width: min(var(--max), calc(100% - (var(--page-gutter) * 2)));
  margin: 36px auto 0;
  padding: 48px 0 24px;
}

.calculator-page-hero h1 {
  max-width: 820px;
}

.calculator-section.standalone {
  margin-top: 28px;
  border-top: 0;
}

.calculator-intro {
  max-width: 760px;
  margin-bottom: 34px;
}

.calculator-intro p {
  margin-top: 18px;
  max-width: 640px;
}

.calculator-shell {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 24px;
  align-items: start;
}

.risk-form,
.result-panel {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  box-shadow: 0 18px 50px rgba(18, 25, 38, 0.08);
}

.risk-form {
  padding: 24px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

label {
  color: #2b303b;
  font-size: 12px;
  font-weight: 800;
}

input,
select {
  width: 100%;
  margin-top: 7px;
  padding: 12px 12px;
  border: 1px solid #d9dde7;
  border-radius: 8px;
  color: var(--ink);
  background: #fff;
  font: inherit;
  font-size: 15px;
}

input:focus,
select:focus {
  outline: 2px solid rgba(36, 60, 201, 0.18);
  border-color: var(--blue);
}

button,
.form-submit-link {
  align-self: end;
  min-height: 46px;
  border: 0;
  border-radius: 8px;
  color: #fff;
  background: var(--ink);
  font: inherit;
  font-weight: 850;
  cursor: pointer;
}

button:hover,
.form-submit-link:hover {
  background: var(--blue);
}

.form-submit-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 16px;
  text-align: center;
}

.result-panel {
  padding: 26px;
  position: sticky;
  top: 20px;
}

.result-topline h3 {
  margin-bottom: 10px;
  font-size: 30px;
}

.result-topline p:not(.eyebrow) {
  margin: 0;
  color: var(--muted);
}

.derived {
  margin: 26px 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.derived div {
  padding: 16px;
}

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

.derived span {
  display: block;
  color: var(--muted);
  font-size: 12px;
  font-weight: 800;
}

.derived strong {
  display: block;
  margin-top: 4px;
  font-size: 28px;
}

.probabilities {
  display: grid;
  gap: 16px;
}

.prob-row {
  display: grid;
  grid-template-columns: 102px 1fr 48px;
  gap: 12px;
  align-items: center;
  font-size: 13px;
  font-weight: 850;
}

.prob-row div {
  height: 10px;
  border-radius: 999px;
  background: #eceff5;
  overflow: hidden;
}

.prob-row i {
  display: block;
  height: 100%;
  width: 0;
  border-radius: inherit;
  transition: width 220ms ease;
}

.normal i {
  background: var(--teal);
}

.osteopenia i {
  background: var(--amber);
}

.osteoporosis i {
  background: var(--red);
}

.panel-note {
  margin-top: 24px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 13px;
}

.table-wrap {
  margin-top: 32px;
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

table {
  width: 100%;
  min-width: 760px;
  border-collapse: collapse;
  background: #fff;
}

th,
td {
  padding: 18px 20px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
  font-size: 14px;
}

th {
  color: var(--muted);
  background: var(--paper);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

tr:last-child td {
  border-bottom: 0;
}

.methods-note {
  padding: 64px 0;
  display: grid;
  grid-template-columns: 1fr 0.86fr;
  gap: 64px;
  border-top: 1px solid var(--line);
}

.site-footer {
  width: min(var(--max), calc(100% - (var(--page-gutter) * 2)));
  margin: 40px auto;
  padding-top: 24px;
  border-top: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  gap: 18px;
  color: var(--muted);
  font-size: 12px;
}

.brand.small {
  color: #333845;
}

@media (max-width: 760px) {
  body {
    min-height: 100vh;
    background:
      linear-gradient(rgba(36, 60, 201, 0.08) 1px, transparent 1px),
      linear-gradient(90deg, rgba(36, 60, 201, 0.08) 1px, transparent 1px),
      #fff;
    background-size: 16px 16px;
  }

  body > .site-header,
  body > main,
  body > .site-footer {
    display: none;
  }

  .mobile-blocker {
    min-height: 100vh;
    width: min(100% - 40px, 520px);
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 18px;
  }

  .mobile-blocker h1 {
    max-width: 420px;
    font-size: 42px;
    line-height: 1;
  }

  .mobile-blocker p {
    max-width: 420px;
    margin: 0;
    color: var(--muted);
    font-size: 18px;
    line-height: 1.35;
    font-weight: 650;
  }

  .mobile-blocker-brand {
    margin-bottom: 8px;
  }
}

@media (min-width: 761px) and (max-width: 900px) {
  .site-header,
  .site-footer {
    flex-wrap: wrap;
  }

  nav {
    order: 3;
    width: 100%;
    justify-content: space-between;
    gap: 12px;
    overflow-x: auto;
  }

  .status-pill {
    margin-left: auto;
  }

  .metrics,
  .content-grid,
  .calculator-shell,
  .methods-note {
    grid-template-columns: 1fr;
  }

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

  .section-title {
    grid-row: auto;
  }

  .risk-form {
    grid-template-columns: repeat(2, 1fr);
  }

  .result-panel {
    position: static;
  }
}

@media (min-width: 761px) and (max-width: 900px) {
  .site-header,
  .hero,
  .calculator-page-hero,
  .content-grid,
  .calculator-section,
  .methods-note,
  .site-footer {
    width: min(100% - 28px, var(--max));
  }

  .login-link {
    display: none;
  }

  .calculator-page .site-header {
    align-items: flex-start;
    gap: 16px;
    padding: 28px 0 18px;
  }

  .calculator-page nav {
    order: 2;
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    width: 100%;
    gap: 10px 14px;
    overflow: visible;
    font-size: 13px;
    line-height: 1.25;
  }

  .calculator-page nav a {
    min-width: 0;
    word-break: keep-all;
  }

  .calculator-page .status-pill {
    order: 1;
    margin-left: 0;
    max-width: 190px;
    white-space: normal;
    text-align: center;
    line-height: 1.2;
  }

  h1 {
    font-size: 48px;
  }

  .calculator-page-hero {
    margin-top: 34px;
    padding: 38px 0 22px;
  }

  .calculator-page-hero h1 {
    font-size: 42px;
    line-height: 0.98;
    max-width: 100%;
  }

  .calculator-page-hero .title-en {
    max-width: 340px;
  }

  .calculator-page-hero .title-cn {
    margin-top: 6px;
    max-width: 310px;
    font-size: 39px;
    line-height: 0.96;
  }

  .lead {
    font-size: 22px;
  }

  .calculator-page .lead {
    font-size: 20px;
    line-height: 1.08;
  }

  .calculator-intro h2 {
    font-size: 32px;
    line-height: 1.05;
  }

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

  .image-strip {
    grid-template-columns: 1fr;
  }

  .image-strip img {
    height: 230px;
  }

  .risk-form {
    grid-template-columns: 1fr;
    padding: 18px;
  }

  .prob-row {
    grid-template-columns: 86px 1fr 40px;
    gap: 10px;
    font-size: 12px;
  }

  .result-panel,
  .shap-card {
    padding: 18px;
  }

  .result-topline h3 {
    font-size: 24px;
  }

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

  .derived div + div {
    border-left: 0;
    border-top: 1px solid var(--line);
  }

  input,
  select,
  button,
  .form-submit-link {
    min-height: 46px;
  }

  .native-shap-figure {
    padding: 8px;
  }

  .shap-plot {
    grid-template-columns: 1fr;
  }

  .native-shap-figure figcaption {
    font-size: 11px;
  }

}

@media (min-width: 761px) and (max-width: 820px) {
  .calculator-page-hero h1 {
    font-size: 38px;
  }

  .calculator-page-hero .title-cn {
    font-size: 34px;
  }

  .calculator-page .lead {
    font-size: 18px;
  }

  .calculator-intro h2 {
    font-size: 29px;
  }
}