:root {
  --sf-ink: #102238;
  --sf-muted: #60748a;
  --sf-line: rgba(50, 92, 128, 0.15);
  --sf-blue: #2d6eea;
  --sf-cyan: #1babc3;
  --sf-mint: #21a98a;
  --sf-surface: rgba(255, 255, 255, 0.9);
  --sf-soft: #f5fafc;
  --sf-shadow: 0 22px 64px rgba(51, 85, 118, 0.12);
  --sf-max: 1320px;
  --sf-font: Inter, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  overflow-x: hidden;
}

body.sf-page {
  margin: 0;
  overflow-x: hidden;
  color: var(--sf-ink);
  background:
    radial-gradient(circle at 12% 8%, rgba(97, 211, 203, 0.1), transparent 28rem),
    radial-gradient(circle at 88% 22%, rgba(82, 135, 235, 0.09), transparent 30rem),
    linear-gradient(180deg, #ffffff 0%, #f7fbfd 42%, #ffffff 100%);
  font-family: var(--sf-font);
}

a {
  color: inherit;
}

.sf-nav {
  position: sticky;
  top: 12px;
  z-index: 30;
  display: grid;
  grid-template-columns: minmax(230px, 0.75fr) minmax(0, 1fr) auto;
  align-items: center;
  gap: 18px;
  width: min(1450px, calc(100% - 32px));
  min-height: 72px;
  margin: 12px auto 0;
  padding: 10px 18px;
  border: 1px solid var(--sf-line);
  border-radius: 28px;
  background: rgba(255, 255, 255, 0.9);
  box-shadow: 0 16px 50px rgba(54, 90, 122, 0.1);
  backdrop-filter: blur(22px) saturate(1.12);
}

.sf-brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  min-width: 0;
  text-decoration: none;
  font-weight: 900;
  letter-spacing: -0.025em;
}

.sf-brand img {
  width: 36px;
  height: 36px;
  padding: 5px;
  border: 1px solid var(--sf-line);
  border-radius: 10px;
  background: #fff;
  object-fit: contain;
}

.sf-navlinks {
  display: flex;
  justify-content: center;
  gap: clamp(16px, 2vw, 34px);
  min-width: 0;
}

.sf-navlinks a,
.sf-actions a,
.sf-actions button {
  min-height: 40px;
  border: 0;
  color: var(--sf-muted);
  background: transparent;
  font: inherit;
  font-size: 13px;
  font-weight: 760;
  text-decoration: none;
  cursor: pointer;
}

.sf-navlinks a {
  display: inline-flex;
  align-items: center;
  white-space: nowrap;
}

.sf-navlinks a:hover,
.sf-navlinks a:focus-visible {
  color: var(--sf-blue);
}

.sf-actions {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 10px;
}

.sf-actions .sf-lang {
  display: inline-flex;
  gap: 3px;
  padding: 3px;
  border: 1px solid var(--sf-line);
  border-radius: 999px;
  background: #fff;
}

.sf-actions .sf-lang button {
  min-width: 38px;
  min-height: 34px;
  padding: 0 9px;
  border-radius: 999px;
}

.sf-actions .sf-lang button[aria-pressed="true"] {
  color: #fff;
  background: linear-gradient(135deg, var(--sf-cyan), var(--sf-blue));
}

.sf-actions .sf-cta,
.sf-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 18px;
  border: 1px solid var(--sf-line);
  border-radius: 999px;
  color: var(--sf-ink);
  background: #fff;
  box-shadow: 0 10px 26px rgba(56, 90, 122, 0.08);
  font-size: 13px;
  font-weight: 860;
  text-decoration: none;
  transition: transform 180ms ease, box-shadow 180ms ease;
}

.sf-actions .sf-cta,
.sf-button.primary {
  border-color: transparent;
  color: #fff;
  background: linear-gradient(135deg, var(--sf-cyan), var(--sf-blue));
}

.sf-button:hover,
.sf-button:focus-visible,
.sf-actions .sf-cta:hover,
.sf-actions .sf-cta:focus-visible {
  transform: translateY(-2px);
  box-shadow: 0 16px 36px rgba(45, 110, 234, 0.18);
}

.sf-main {
  width: min(var(--sf-max), calc(100% - 40px));
  margin: 0 auto;
}

.sf-hero {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.02fr) minmax(440px, 0.98fr);
  gap: clamp(48px, 6vw, 88px);
  align-items: center;
  min-height: 660px;
  padding: clamp(76px, 9vw, 128px) 0 clamp(70px, 8vw, 110px);
}

.sf-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 30px;
  margin: 0 0 18px;
  padding: 0 11px;
  border: 1px solid rgba(33, 169, 138, 0.18);
  border-radius: 999px;
  color: #0d7e69;
  background: rgba(231, 250, 246, 0.84);
  font-size: 11px;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.sf-eyebrow::before {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--sf-mint);
  box-shadow: 0 0 0 5px rgba(33, 169, 138, 0.1);
  content: "";
}

.sf-hero h1 {
  max-width: 900px;
  margin: 0;
  font-size: clamp(48px, 6.1vw, 86px);
  font-weight: 900;
  line-height: 0.98;
  letter-spacing: -0.055em;
  text-wrap: balance;
}

.sf-answer {
  max-width: 760px;
  margin: 26px 0 0;
  color: var(--sf-muted);
  font-size: clamp(17px, 1.35vw, 20px);
  line-height: 1.78;
}

.sf-hero-actions,
.sf-section-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.sf-proofline {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 24px;
}

.sf-proofline span {
  padding: 8px 11px;
  border: 1px solid var(--sf-line);
  border-radius: 999px;
  color: var(--sf-muted);
  background: rgba(255, 255, 255, 0.78);
  font-size: 11px;
  font-weight: 760;
}

.sf-visual {
  position: relative;
  min-height: 520px;
  overflow: hidden;
  border: 1px solid rgba(67, 119, 164, 0.16);
  border-radius: 34px;
  background:
    radial-gradient(circle at 50% 50%, rgba(70, 219, 209, 0.2), transparent 16rem),
    linear-gradient(145deg, rgba(255, 255, 255, 0.96), rgba(234, 246, 252, 0.9));
  box-shadow: var(--sf-shadow);
}

.sf-visual img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.72;
}

.sf-circuit {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

.sf-circuit path {
  fill: none;
  stroke: rgba(36, 174, 194, 0.7);
  stroke-width: 2;
  stroke-linecap: round;
  stroke-dasharray: 12 16;
  animation: sf-flow 5.5s linear infinite;
}

.sf-circuit circle {
  fill: #eaffff;
  stroke: rgba(45, 110, 234, 0.76);
  stroke-width: 2;
  filter: drop-shadow(0 0 8px rgba(41, 167, 208, 0.45));
  animation: sf-pulse 2.2s ease-in-out infinite;
}

.sf-circuit circle:nth-of-type(2n) {
  animation-delay: -0.8s;
}

.sf-visual-card {
  position: absolute;
  right: 28px;
  bottom: 28px;
  left: 28px;
  z-index: 2;
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 14px;
  padding: 22px;
  border: 1px solid rgba(55, 100, 142, 0.16);
  border-radius: 22px;
  background: rgba(255, 255, 255, 0.9);
  box-shadow: 0 16px 46px rgba(42, 82, 118, 0.13);
  backdrop-filter: blur(18px);
}

.sf-visual-card strong {
  font-size: 20px;
  line-height: 1.2;
}

.sf-visual-card span {
  color: var(--sf-muted);
  font-size: 12px;
  line-height: 1.6;
}

.sf-section {
  padding: clamp(74px, 8vw, 118px) 0;
}

.sf-section + .sf-section {
  border-top: 1px solid rgba(49, 89, 128, 0.09);
}

.sf-heading {
  display: grid;
  grid-template-columns: minmax(0, 0.75fr) minmax(0, 1.25fr);
  gap: clamp(36px, 6vw, 88px);
  align-items: end;
  margin-bottom: clamp(38px, 5vw, 64px);
}

.sf-heading h2 {
  margin: 0;
  font-size: clamp(36px, 4.8vw, 64px);
  line-height: 1.03;
  letter-spacing: -0.045em;
  text-wrap: balance;
}

.sf-heading p {
  max-width: 620px;
  margin: 0;
  color: var(--sf-muted);
  font-size: 16px;
  line-height: 1.75;
}

.sf-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}

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

.sf-card {
  position: relative;
  min-width: 0;
  padding: clamp(24px, 2.8vw, 36px);
  overflow: hidden;
  border: 1px solid var(--sf-line);
  border-radius: 26px;
  background: var(--sf-surface);
  box-shadow: 0 14px 42px rgba(49, 84, 116, 0.08);
}

.sf-card::after {
  position: absolute;
  right: -54px;
  bottom: -54px;
  width: 150px;
  height: 150px;
  border: 1px solid rgba(45, 110, 234, 0.09);
  border-radius: 50%;
  box-shadow: inset 0 0 0 22px rgba(27, 171, 195, 0.035);
  content: "";
}

.sf-card small {
  display: block;
  margin-bottom: 16px;
  color: var(--sf-cyan);
  font-size: 10px;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.sf-card h3 {
  margin: 0 0 13px;
  font-size: clamp(21px, 2vw, 29px);
  line-height: 1.18;
  letter-spacing: -0.03em;
}

.sf-card p,
.sf-card li {
  color: var(--sf-muted);
  font-size: 14px;
  line-height: 1.72;
}

.sf-card ul,
.sf-checklist {
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}

.sf-card li,
.sf-checklist li {
  position: relative;
  padding: 9px 0 9px 22px;
  border-top: 1px solid rgba(52, 92, 128, 0.1);
}

.sf-card li::before,
.sf-checklist li::before {
  position: absolute;
  left: 2px;
  color: var(--sf-cyan);
  font-weight: 900;
  content: "✓";
}

.sf-timeline {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  overflow: hidden;
  border: 1px solid var(--sf-line);
  border-radius: 28px;
  background: rgba(255, 255, 255, 0.88);
}

.sf-step {
  min-height: 260px;
  padding: 30px;
}

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

.sf-step b {
  display: block;
  color: var(--sf-cyan);
  font-size: 34px;
  font-weight: 500;
  font-style: italic;
}

.sf-step h3 {
  margin: 32px 0 12px;
  font-size: 19px;
}

.sf-step p {
  color: var(--sf-muted);
  font-size: 13px;
  line-height: 1.7;
}

.sf-proof {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(360px, 0.85fr);
  gap: 28px;
  align-items: stretch;
}

.sf-proof figure {
  min-height: 460px;
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--sf-line);
  border-radius: 30px;
  background: #eff7fb;
  box-shadow: var(--sf-shadow);
}

.sf-proof figure img {
  width: 100%;
  height: 100%;
  min-height: 460px;
  object-fit: cover;
}

.sf-proof-copy {
  padding: clamp(28px, 4vw, 46px);
  border: 1px solid var(--sf-line);
  border-radius: 30px;
  background: rgba(255, 255, 255, 0.9);
}

.sf-proof-copy h2 {
  margin: 0 0 18px;
  font-size: clamp(31px, 3.7vw, 48px);
  line-height: 1.06;
  letter-spacing: -0.04em;
}

.sf-proof-copy p,
.sf-proof-copy li {
  color: var(--sf-muted);
  line-height: 1.74;
}

.sf-faq {
  display: grid;
  gap: 12px;
}

.sf-faq details {
  padding: 22px 26px;
  border: 1px solid var(--sf-line);
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.9);
}

.sf-faq summary {
  cursor: pointer;
  font-weight: 820;
}

.sf-faq p {
  margin: 16px 0 0;
  color: var(--sf-muted);
  line-height: 1.7;
}

.sf-callout {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 34px;
  align-items: center;
  margin: 0 0 clamp(80px, 9vw, 130px);
  padding: clamp(34px, 5vw, 66px);
  overflow: hidden;
  border: 1px solid rgba(48, 109, 207, 0.14);
  border-radius: 34px;
  background:
    radial-gradient(circle at 83% 18%, rgba(64, 215, 201, 0.22), transparent 16rem),
    linear-gradient(135deg, #f7fcff, #edf7ff);
  box-shadow: var(--sf-shadow);
}

.sf-callout h2 {
  max-width: 860px;
  margin: 0;
  font-size: clamp(34px, 4.6vw, 62px);
  line-height: 1.02;
  letter-spacing: -0.045em;
}

.sf-callout p {
  max-width: 760px;
  margin: 18px 0 0;
  color: var(--sf-muted);
  line-height: 1.7;
}

.sf-breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  padding-top: 34px;
  color: var(--sf-muted);
  font-size: 12px;
}

.sf-breadcrumb a {
  text-decoration: none;
}

.sf-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 18px 0 0;
  color: var(--sf-muted);
  font-size: 12px;
}

.sf-meta span {
  padding: 7px 10px;
  border: 1px solid var(--sf-line);
  border-radius: 999px;
  background: #fff;
}

.sf-toc {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px 18px;
  margin: 30px 0 0;
  padding: 22px;
  border: 1px solid var(--sf-line);
  border-radius: 22px;
  background: rgba(255, 255, 255, 0.76);
}

.sf-toc a {
  color: var(--sf-muted);
  font-size: 13px;
  text-decoration: none;
}

.sf-report {
  max-width: 980px;
  margin: 0 auto;
}

.sf-report-section {
  padding: 50px 0;
  border-top: 1px solid var(--sf-line);
}

.sf-report-section h2 {
  margin: 0 0 18px;
  font-size: clamp(30px, 4vw, 48px);
  line-height: 1.08;
  letter-spacing: -0.035em;
}

.sf-report-section p,
.sf-report-section li {
  color: var(--sf-muted);
  line-height: 1.76;
}

.sf-check-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.sf-check {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  padding: 18px;
  border: 1px solid var(--sf-line);
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.88);
}

.sf-check input {
  width: 20px;
  height: 20px;
  margin: 2px 0 0;
  accent-color: var(--sf-blue);
}

.sf-check span {
  color: var(--sf-muted);
  font-size: 13px;
  line-height: 1.55;
}

.sf-score {
  position: sticky;
  bottom: 18px;
  z-index: 8;
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 16px;
  align-items: center;
  margin: 28px 0 0;
  padding: 16px 20px;
  border: 1px solid rgba(45, 110, 234, 0.18);
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.94);
  box-shadow: 0 16px 44px rgba(47, 84, 118, 0.14);
  backdrop-filter: blur(18px);
}

.sf-score-track {
  height: 8px;
  overflow: hidden;
  border-radius: 999px;
  background: #e8f0f5;
}

.sf-score-track i {
  display: block;
  width: 0;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--sf-cyan), var(--sf-blue));
  transition: width 220ms ease;
}

.sf-source-list {
  display: grid;
  gap: 10px;
  padding: 0;
  list-style: none;
}

.sf-source-list a {
  color: var(--sf-blue);
  overflow-wrap: anywhere;
}

.sf-footer {
  width: min(var(--sf-max), calc(100% - 40px));
  margin: 0 auto 30px;
  padding: 28px 0;
  border-top: 1px solid var(--sf-line);
  color: var(--sf-muted);
  font-size: 12px;
}

.sf-footer > div {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 18px;
}

.sf-footer nav {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.sf-footer a {
  text-decoration: none;
}

@keyframes sf-flow {
  to {
    stroke-dashoffset: -112;
  }
}

@keyframes sf-pulse {
  0%,
  100% {
    opacity: 0.45;
    transform: scale(0.82);
    transform-origin: center;
  }
  50% {
    opacity: 1;
    transform: scale(1.16);
  }
}

@media (max-width: 1050px) {
  .sf-nav {
    grid-template-columns: 1fr auto;
  }

  .sf-navlinks {
    grid-column: 1 / -1;
    grid-row: 2;
    justify-content: flex-start;
    overflow-x: auto;
  }

  .sf-hero,
  .sf-proof {
    grid-template-columns: 1fr;
  }

  .sf-visual {
    min-height: 470px;
  }

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

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

  .sf-step:nth-child(3) {
    border-left: 0;
    border-top: 1px solid var(--sf-line);
  }

  .sf-step:nth-child(4) {
    border-top: 1px solid var(--sf-line);
  }
}

@media (max-width: 680px) {
  .sf-nav {
    top: 8px;
    grid-template-columns: minmax(0, 1fr);
    gap: 8px;
    width: calc(100% - 20px);
    padding: 9px;
    border-radius: 22px;
  }

  .sf-brand {
    font-size: 14px;
  }

  .sf-actions {
    grid-row: 2;
    justify-content: flex-start;
    overflow-x: auto;
  }

  .sf-navlinks {
    grid-row: 3;
    gap: 18px;
    padding: 4px 2px;
  }

  .sf-actions > a:not(.sf-cta) {
    display: none;
  }

  .sf-main,
  .sf-footer {
    width: calc(100% - 24px);
  }

  .sf-hero {
    grid-template-columns: 1fr;
    gap: 34px;
    min-height: 0;
    padding: 56px 0 70px;
  }

  .sf-hero h1 {
    font-size: clamp(39px, 13vw, 58px);
  }

  .sf-visual {
    min-height: 430px;
    border-radius: 24px;
  }

  .sf-visual-card {
    right: 14px;
    bottom: 14px;
    left: 14px;
    grid-template-columns: 1fr;
  }

  .sf-heading {
    grid-template-columns: 1fr;
    gap: 18px;
  }

  .sf-grid,
  .sf-grid.two,
  .sf-check-grid,
  .sf-toc {
    grid-template-columns: 1fr;
  }

  .sf-timeline {
    grid-template-columns: 1fr;
  }

  .sf-step + .sf-step,
  .sf-step:nth-child(3),
  .sf-step:nth-child(4) {
    border-top: 1px solid var(--sf-line);
    border-left: 0;
  }

  .sf-proof figure,
  .sf-proof figure img {
    min-height: 330px;
  }

  .sf-callout {
    grid-template-columns: 1fr;
  }

  .sf-score {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .sf-circuit path,
  .sf-circuit circle {
    animation: none;
  }

  .sf-button,
  .sf-actions .sf-cta {
    transition: none;
  }
}