:root {
  --background: #f4f7fb;
  --surface: #ffffff;
  --text: #172033;
  --muted: #5f6b7a;
  --primary: #2563eb;
  --primary-soft: #eaf1ff;
  --border: #dce4ef;
  --warning: #92400e;
  --warning-background: #fff7ed;
  --warning-border: #fdba74;
  --shadow: 0 16px 45px rgba(23, 32, 51, 0.08);
  --radius-large: 24px;
  --radius-medium: 16px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--background);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  line-height: 1.7;
}

.container {
  width: min(1080px, calc(100% - 40px));
  margin: 0 auto;
}

.hero {
  padding: 76px 0 112px;
  color: #ffffff;
  background:
    radial-gradient(circle at 85% 20%, rgba(255, 255, 255, 0.2), transparent 28%),
    linear-gradient(135deg, #1d4ed8 0%, #2563eb 56%, #4f46e5 100%);
}

.eyebrow,
.section-heading span {
  display: block;
  margin-bottom: 8px;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.hero h1 {
  margin: 0;
  font-size: clamp(38px, 7vw, 64px);
  line-height: 1.15;
}

.hero-copy {
  max-width: 680px;
  margin: 20px 0 0;
  color: rgba(255, 255, 255, 0.85);
  font-size: 18px;
}

main {
  position: relative;
  margin-top: -56px !important;
  padding-bottom: 80px;
}

.security-notice {
  display: flex;
  gap: 18px;
  align-items: flex-start;
  padding: 24px;
  border: 1px solid var(--warning-border);
  border-radius: var(--radius-large);
  background: var(--warning-background);
  color: var(--warning);
  box-shadow: var(--shadow);
}

.notice-icon {
  display: grid;
  flex: 0 0 38px;
  width: 38px;
  height: 38px;
  place-items: center;
  border-radius: 50%;
  background: #f97316;
  color: #ffffff;
  font-size: 22px;
  font-weight: 800;
}

.security-notice h2,
.security-notice p {
  margin: 0;
}

.security-notice h2 {
  margin-bottom: 4px;
  font-size: 20px;
}

.section {
  padding-top: 72px;
}

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

.section-heading span {
  color: var(--primary);
}

.section-heading h2 {
  margin: 0;
  font-size: clamp(28px, 5vw, 40px);
  line-height: 1.3;
}

.steps {
  display: grid;
  gap: 24px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.step-card {
  display: grid;
  grid-template-columns: 72px minmax(0, 1fr);
  gap: 24px;
  padding: 28px;
  border: 1px solid var(--border);
  border-radius: var(--radius-large);
  background: var(--surface);
  box-shadow: 0 8px 30px rgba(23, 32, 51, 0.05);
}

.step-number {
  display: grid;
  width: 58px;
  height: 58px;
  place-items: center;
  border-radius: 18px;
  background: var(--primary-soft);
  color: var(--primary);
  font-weight: 800;
}

.step-content h3 {
  margin: 4px 0 8px;
  font-size: 24px;
}

.step-content p {
  margin: 0 0 22px;
  color: var(--muted);
}

.image-placeholder {
  display: grid;
  min-height: 250px;
  place-content: center;
  gap: 6px;
  padding: 24px;
  border: 2px dashed #b7c5d8;
  border-radius: var(--radius-medium);
  background:
    linear-gradient(135deg, rgba(37, 99, 235, 0.035) 25%, transparent 25%) 0 0 / 24px 24px,
    #f8fafc;
  color: #496076;
  text-align: center;
}

.image-placeholder span {
  font-weight: 700;
}

.image-placeholder small {
  color: #7b8a9c;
}

.tutorial-image {
  display: block;
  width: min(100%, 720px);
  aspect-ratio: 16 / 9;
  margin: 18px auto 0;
  border: 1px solid var(--border);
  border-radius: var(--radius-medium);
  background: #f4f7fb;
  object-fit: contain;
  cursor: zoom-in;
}

.tutorial-image:focus-visible {
  outline: 3px solid rgba(37, 99, 235, 0.4);
  outline-offset: 4px;
}

.contact-copy-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

.copy-button {
  min-height: 40px;
  padding: 8px 16px;
  border: 0;
  border-radius: 10px;
  background: #2563eb;
  color: #ffffff;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}

.copy-button:hover {
  background: #1d4ed8;
}

.copy-button:focus-visible {
  outline: 3px solid rgba(37, 99, 235, 0.4);
  outline-offset: 3px;
}

.copy-button-light {
  background: #ffffff;
  color: #172033;
}

.copy-button-light:hover {
  background: #eaf1ff;
}

.image-dialog {
  width: min(94vw, 1280px);
  max-width: none;
  padding: 48px 18px 18px;
  border: 0;
  border-radius: 18px;
  background: #111827;
}

.image-dialog::backdrop {
  background: rgba(0, 0, 0, 0.82);
}

.image-dialog img {
  display: block;
  width: 100%;
  max-height: 82vh;
  object-fit: contain;
}

.dialog-close {
  position: absolute;
  top: 8px;
  right: 12px;
  width: 38px;
  height: 38px;
  border: 0;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.14);
  color: #ffffff;
  font-size: 28px;
  line-height: 1;
  cursor: pointer;
}

.review-placeholder {
  display: grid;
  gap: 6px;
  padding: 20px;
  border: 1px solid var(--warning-border);
  border-radius: var(--radius-medium);
  background: var(--warning-background);
  color: var(--warning);
}

.review-placeholder span {
  color: #9a4d10;
}

.step-content a {
  color: var(--primary);
  font-weight: 700;
  text-underline-offset: 3px;
}

.step-content a:focus-visible {
  outline: 3px solid rgba(37, 99, 235, 0.35);
  outline-offset: 3px;
}

.faq-list {
  display: grid;
  gap: 14px;
}

.faq-list details {
  border: 1px solid var(--border);
  border-radius: var(--radius-medium);
  background: var(--surface);
  overflow: hidden;
}

.faq-list summary {
  padding: 20px 22px;
  cursor: pointer;
  font-size: 18px;
  font-weight: 700;
}

.faq-list summary:focus-visible {
  outline: 3px solid rgba(37, 99, 235, 0.35);
  outline-offset: -3px;
}

.faq-list details p {
  margin: 0;
  padding: 0 22px 22px;
  color: var(--muted);
}

.contact-card {
  display: grid;
  grid-template-columns: 1fr minmax(260px, 0.7fr);
  gap: 32px;
  align-items: center;
  margin-top: 72px;
  padding: 34px;
  border-radius: var(--radius-large);
  background: var(--text);
  color: #ffffff;
}

.contact-card h2,
.contact-card p {
  margin: 0;
}

.contact-card h2 {
  margin-bottom: 8px;
  font-size: 28px;
}

.contact-card p {
  color: rgba(255, 255, 255, 0.7);
}

.contact-card .eyebrow {
  color: #93c5fd;
}

.contact-placeholder {
  display: grid;
  gap: 3px;
  padding: 20px;
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-medium);
  background: rgba(255, 255, 255, 0.08);
}

.contact-placeholder span {
  color: rgba(255, 255, 255, 0.65);
  font-size: 14px;
}

footer {
  padding: 30px 0;
  border-top: 1px solid var(--border);
  background: var(--surface);
  color: var(--muted);
  font-size: 14px;
}

footer .container {
  display: flex;
  justify-content: space-between;
  gap: 24px;
}

footer p {
  margin: 0;
}

@media (max-width: 720px) {
  .container {
    width: min(100% - 28px, 1080px);
  }

  .hero {
    padding: 56px 0 96px;
  }

  .hero-copy {
    font-size: 16px;
  }

  .security-notice {
    padding: 20px;
  }

  .section {
    padding-top: 52px;
  }

  .step-card {
    grid-template-columns: 1fr;
    gap: 14px;
    padding: 20px;
  }

  .step-number {
    width: 48px;
    height: 48px;
    border-radius: 14px;
  }

  .step-content h3 {
    font-size: 21px;
  }

  .image-placeholder {
    min-height: 190px;
  }

  .contact-card {
    grid-template-columns: 1fr;
    padding: 26px 22px;
  }

  footer .container {
    flex-direction: column;
    gap: 8px;
  }
}

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