:root {
  --bg: #f2f6fc;
  --paper: #ffffff;
  --ink: #16202e;
  --muted: #647489;
  --blue: #2f6bff;
  --blue-deep: #1a44b8;
  --lime: #b6f24c;
  --soft: #e7eefc;
  --line: #dbe4f2;
  --shell: 1140px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background:
    radial-gradient(680px 360px at 92% -8%, rgba(47, 107, 255, 0.14), transparent 62%),
    radial-gradient(420px 300px at 0% 44%, rgba(182, 242, 76, 0.12), transparent 60%),
    var(--bg);
  color: var(--ink);
  font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.78;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
p { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
img { display: block; max-width: 100%; height: auto; }
h1, h2, h3 { margin: 0; line-height: 1.3; font-weight: 700; }

.page-shell {
  width: 100%;
  max-width: var(--shell);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: rgba(255, 255, 255, 0.93);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}

.nav-shell {
  max-width: var(--shell);
  margin: 0 auto;
  padding: 12px 24px;
  display: flex;
  align-items: center;
  gap: 18px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  white-space: nowrap;
}

.brand img {
  width: 38px;
  height: 38px;
  border-radius: 11px;
  object-fit: cover;
  border: 1px solid var(--line);
}

.primary-nav { margin-left: auto; }

.primary-nav ul {
  display: flex;
  align-items: center;
  gap: 21px;
  font-size: 14.5px;
  color: var(--muted);
}

.primary-nav a {
  display: inline-block;
  padding: 5px 0;
  transition: color 0.2s ease;
}

.primary-nav a:hover { color: var(--blue); }

.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.nav-download {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 17px;
  border-radius: 9px;
  background: var(--blue);
  color: #fff;
  font-size: 14.5px;
  font-weight: 700;
  transition: background 0.18s ease;
}

.nav-download svg {
  width: 17px;
  height: 17px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.nav-download:hover { background: var(--blue-deep); }

.menu-toggle {
  display: none;
  width: 40px;
  height: 40px;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: var(--paper);
  cursor: pointer;
  padding: 0;
}

.menu-toggle span {
  display: block;
  width: 16px;
  height: 2px;
  margin: 3px auto;
  border-radius: 2px;
  background: var(--ink);
}

/* ---------- hero ---------- */
.hero {
  padding: 56px 0 46px;
  overflow: hidden;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 0.86fr);
  gap: 46px;
  align-items: center;
}

.hero-kicker {
  font-size: 12px;
  letter-spacing: 0.13em;
  font-weight: 700;
  color: var(--blue);
}

.hero h1 {
  margin: 12px 0 10px;
  font-size: clamp(32px, 4.5vw, 52px);
  letter-spacing: -0.015em;
}

.hero-subtitle {
  font-size: clamp(17px, 1.9vw, 21px);
  font-weight: 700;
  color: var(--blue-deep);
}

.hero-lead {
  margin-top: 16px;
  max-width: 470px;
  color: var(--muted);
  font-size: 15.5px;
}

.hero-actions {
  margin-top: 26px;
  display: flex;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
}

.button {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 13px 24px;
  border-radius: 9px;
  font-weight: 700;
  font-size: 15.5px;
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}

.button svg {
  width: 18px;
  height: 18px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.button-primary {
  background: var(--blue);
  color: #fff;
  box-shadow: 0 14px 28px rgba(47, 107, 255, 0.24);
}

.button-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 18px 34px rgba(47, 107, 255, 0.3);
}

.button-large { padding: 15px 30px; font-size: 16.5px; }

.text-link {
  font-size: 14.5px;
  font-weight: 600;
  color: var(--muted);
  border-bottom: 1px dashed #bccbe2;
  padding-bottom: 2px;
}

.text-link:hover { color: var(--blue); }

.hero-tags {
  margin-top: 28px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  font-size: 13px;
  color: var(--muted);
}

.hero-tags li {
  padding: 4px 12px;
  border-radius: 6px;
  background: var(--paper);
  border: 1px solid var(--line);
}

.hero-tags b { color: var(--blue); }

/* ---------- hero ladder panel ---------- */
.ladder-panel {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 18px;
  box-shadow: 0 22px 46px rgba(22, 32, 46, 0.1);
}

.ladder-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line);
}

.ladder-head p {
  font-size: 14px;
  font-weight: 800;
}

.ladder-head span {
  font-size: 11.5px;
  font-weight: 700;
  color: #33530a;
  background: var(--lime);
  border-radius: 999px;
  padding: 3px 10px;
}

.ladder-list {
  padding: 10px 0;
}

.ladder-list li {
  display: grid;
  grid-template-columns: 52px minmax(0, 1fr) auto;
  align-items: center;
  gap: 10px;
  padding: 11px 12px;
  border-radius: 9px;
  border: 1px solid transparent;
  transition: background 0.18s ease;
}

.ladder-list li + li { margin-top: 5px; }

.ladder-list li:nth-child(2) { background: #f7faff; border-color: #eaf0fb; }
.ladder-list li:nth-child(3) { background: #f7faff; border-color: #eaf0fb; }
.ladder-list li:nth-child(4) { background: #f7faff; border-color: #eaf0fb; }

.ladder-list li.is-active {
  background: linear-gradient(100deg, #eef4ff, #f6fff0);
  border-color: #c9dbff;
}

.ladder-list b {
  font-size: 15px;
  font-weight: 800;
  color: var(--ink);
}

.ladder-list small {
  font-size: 12px;
  color: var(--muted);
}

.ladder-list em {
  font-size: 11px;
  font-style: normal;
  font-weight: 700;
  color: var(--muted);
  background: #eef2f9;
  border-radius: 4px;
  padding: 2px 7px;
  white-space: nowrap;
}

.ladder-list .is-active em {
  color: #1c4f00;
  background: var(--lime);
}

.ladder-foot {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px;
  padding-top: 11px;
  border-top: 1px dashed var(--line);
  font-size: 11.5px;
  color: var(--muted);
}

/* ---------- section shared ---------- */
section { padding: 52px 0; }

.section-heading {
  max-width: 660px;
  margin-bottom: 28px;
}

.section-heading .eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-size: 11.5px;
  letter-spacing: 0.14em;
  font-weight: 700;
  color: var(--blue);
  margin-bottom: 10px;
}

.section-heading .eyebrow::before {
  content: "";
  width: 14px;
  height: 3px;
  border-radius: 2px;
  background: var(--lime);
}

.section-heading h2 { font-size: clamp(23px, 2.8vw, 31px); }

.section-heading p:last-child {
  margin-top: 10px;
  color: var(--muted);
  font-size: 14.5px;
}

.section-heading-split {
  max-width: none;
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px;
}

.section-heading-split > p {
  margin: 0 0 6px;
  color: var(--muted);
  font-size: 13.5px;
  white-space: nowrap;
}

/* ---------- features ---------- */
.features {
  background: var(--paper);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.switch-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: 12px;
  overflow: hidden;
}

.switch-grid article {
  background: var(--paper);
  padding: 22px 18px 24px;
  transition: background 0.18s ease;
}

.switch-grid article:hover { background: #f7faff; }

.switch-grid span {
  display: inline-block;
  font-size: 11.5px;
  font-weight: 700;
  color: var(--blue);
  border-bottom: 2px solid var(--lime);
  padding-bottom: 2px;
  margin-bottom: 9px;
}

.switch-grid h3 {
  font-size: 17.5px;
  margin-bottom: 6px;
}

.switch-grid p {
  font-size: 13.6px;
  color: var(--muted);
}

/* ---------- shots ---------- */
.frame-row {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.frame-row figure {
  margin: 0;
  border-radius: 12px;
  overflow: hidden;
  background: var(--paper);
  border: 1px solid var(--line);
}

.frame-row img {
  width: 100%;
  aspect-ratio: 3 / 5;
  object-fit: cover;
  object-position: top center;
  background: #eaf0f9;
}

.frame-row figcaption {
  display: flex;
  align-items: baseline;
  gap: 7px;
  padding: 10px 13px 12px;
  font-size: 13px;
  font-weight: 700;
}

.frame-row figcaption b {
  font-size: 11px;
  color: var(--blue);
}

.frame-row figcaption small {
  margin-left: auto;
  font-weight: 400;
  font-size: 11px;
  color: var(--muted);
}

.sample-note {
  margin-top: 16px;
  font-size: 12.5px;
  color: var(--muted);
}

/* ---------- faq ---------- */
.faq {
  background: linear-gradient(180deg, #eaf1fd, #f2f6fc 62%);
  border-top: 1px solid var(--line);
}

.faq-rows {
  display: grid;
  gap: 8px;
  max-width: 900px;
}

.faq-rows details {
  border-radius: 10px;
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 0 18px;
  transition: border-color 0.18s ease;
}

.faq-rows details[open] { border-color: #b9cffb; }

.faq-rows summary {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 0;
  cursor: pointer;
  list-style: none;
}

.faq-rows summary::-webkit-details-marker { display: none; }

.faq-rows summary h3 {
  flex: 1;
  font-size: 15.5px;
}

.faq-rows summary i {
  position: relative;
  flex: none;
  width: 20px;
  height: 20px;
  border-radius: 6px;
  background: var(--soft);
}

.faq-rows summary i::before,
.faq-rows summary i::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  background: var(--blue);
  border-radius: 2px;
  transform: translate(-50%, -50%);
}

.faq-rows summary i::before { width: 9px; height: 2px; }
.faq-rows summary i::after { width: 2px; height: 9px; transition: opacity 0.2s ease; }
.faq-rows details[open] summary i::after { opacity: 0; }

.faq-rows details > p {
  padding: 12px 0 15px;
  border-top: 1px dashed var(--line);
  font-size: 14px;
  color: var(--muted);
}

/* ---------- reviews ---------- */
.reviews { background: var(--paper); border-top: 1px solid var(--line); }

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

.review-card {
  padding: 16px 18px;
  border-radius: 10px;
  background: #f7faff;
  border: 1px solid var(--line);
}

.review-card > p {
  font-size: 14px;
  color: #2c3a4c;
}

.review-meta {
  margin-top: 12px;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding-top: 10px;
  border-top: 1px dashed var(--line);
  font-size: 11.5px;
  color: var(--muted);
}

.review-meta b {
  font-size: 12.5px;
  color: var(--blue-deep);
}

/* ---------- steps ---------- */
.step-cards {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.step-cards li {
  padding: 20px 20px 22px;
  border-radius: 12px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-top: 3px solid var(--blue);
}

.step-cards li:nth-child(2) { border-top-color: #7f9dff; }
.step-cards li:nth-child(3) { border-top-color: var(--lime); }

.step-cards span {
  display: block;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.1em;
  color: var(--blue);
  margin-bottom: 8px;
}

.step-cards h3 {
  font-size: 17px;
  margin-bottom: 5px;
}

.step-cards p {
  font-size: 13.6px;
  color: var(--muted);
}

/* ---------- download ---------- */
.download { padding-bottom: 64px; }

.download-panel {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 34px;
  padding: 34px;
  border-radius: 16px;
  background: linear-gradient(118deg, #1d3fd0, var(--blue));
  color: #fff;
  box-shadow: 0 22px 46px rgba(47, 107, 255, 0.26);
}

.download-copy { max-width: 520px; }

.download-copy .eyebrow {
  font-size: 11.5px;
  letter-spacing: 0.16em;
  font-weight: 700;
  color: #cfe0ff;
  margin-bottom: 8px;
}

.download-copy h2 {
  font-size: clamp(23px, 2.7vw, 30px);
  margin-bottom: 8px;
}

.download-copy p { font-size: 14.5px; color: #dce8ff; }

.download-act {
  flex: none;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 12px;
}

.download-act .button-primary {
  background: #fff;
  color: var(--blue-deep);
  box-shadow: 0 12px 26px rgba(0, 0, 0, 0.16);
}

.download-notes {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 14px;
  font-size: 12px;
  color: #dce8ff;
}

.download-notes li {
  display: inline-flex;
  align-items: center;
  gap: 5px;
}

.download-notes li::before {
  content: "";
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--lime);
}

/* ---------- footer ---------- */
.site-footer {
  background: #101a28;
  color: #b9c7d8;
  padding: 34px 0 30px;
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr) minmax(0, 0.8fr);
  gap: 22px 30px;
  align-items: start;
}

.footer-brand strong {
  display: block;
  font-size: 17px;
  color: #fff;
}

.footer-brand p {
  margin-top: 4px;
  font-size: 12.5px;
  color: #899bb1;
}

.footer-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  font-size: 13px;
}

.footer-nav a:hover { color: #fff; }

.footer-meta {
  font-size: 12.5px;
  color: #899bb1;
  text-align: right;
}

.footer-meta a { color: #b9c7d8; }

.disclaimer {
  grid-column: 1 / -1;
  padding-top: 16px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  font-size: 12px;
  line-height: 1.7;
  color: #7f90a6;
}

/* ---------- responsive ---------- */
@media (max-width: 980px) {
  .hero-grid { grid-template-columns: minmax(0, 1fr); gap: 34px; }
  .ladder-panel { max-width: 520px; }
  .switch-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .frame-row { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-meta { text-align: left; }
  .download-panel { flex-direction: column; align-items: flex-start; }
}

@media (max-width: 900px) {
  .primary-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    margin-left: 0;
    display: none;
    background: var(--paper);
    border-bottom: 1px solid var(--line);
    padding: 10px 24px 16px;
  }

  .primary-nav.is-open { display: block; }

  .primary-nav ul {
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    font-size: 15px;
  }

  .primary-nav li { width: 100%; }

  .primary-nav a {
    display: block;
    padding: 11px 0;
    border-bottom: 1px solid var(--line);
  }

  .nav-shell { position: relative; flex-wrap: wrap; }
  .primary-nav { order: 4; flex-basis: 100%; }
  .nav-actions { margin-left: auto; }
  .menu-toggle { display: block; }
  .nav-download span { display: none; }
  .nav-download { padding: 10px 12px; }
}

@media (max-width: 640px) {
  .page-shell, .nav-shell { padding-left: 18px; padding-right: 18px; }
  section { padding: 42px 0; }
  .hero { padding: 40px 0 34px; }
  .switch-grid { grid-template-columns: minmax(0, 1fr); }
  .say-grid { grid-template-columns: minmax(0, 1fr); }
  .step-cards { grid-template-columns: minmax(0, 1fr); }
  .section-heading-split { flex-direction: column; align-items: flex-start; gap: 6px; }
  .section-heading-split > p { white-space: normal; }
  .download-panel { padding: 26px 20px; }
  .footer-grid { grid-template-columns: minmax(0, 1fr); }
  .download-act { width: 100%; }
  .download-act .button { width: 100%; justify-content: center; }
}

@media (max-width: 400px) {
  .frame-row { grid-template-columns: minmax(0, 1fr); }
  .brand span { font-size: 15px; }
  .ladder-list li { grid-template-columns: 46px minmax(0, 1fr) auto; padding: 10px 8px; }
}