/* ==========================================================================
   cfrp-sawatetsu.com — Airbnb DESIGN.md 準拠スタイル
   Tokens: Airbnb-design-analysis (Rausch #ff385c / Cereal→Inter / 白基調・グラデ無し)
   ========================================================================== */

*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  /* Colors (Airbnb tokens) */
  --primary: #ff385c;        /* Rausch */
  --primary-active: #e00b41;
  --ink: #222222;
  --body: #3f3f3f;
  --muted: #6a6a6a;
  --muted-soft: #929292;
  --hairline: #dddddd;
  --hairline-soft: #ebebeb;
  --canvas: #ffffff;
  --surface-soft: #f7f7f7;
  --surface-strong: #f2f2f2;
  --on-primary: #ffffff;

  /* Radius */
  --r-sm: 8px;    /* buttons */
  --r-md: 14px;   /* cards */
  --r-full: 9999px;

  /* The single Airbnb shadow tier */
  --shadow: rgba(0, 0, 0, 0.02) 0 0 0 1px, rgba(0, 0, 0, 0.04) 0 2px 6px 0, rgba(0, 0, 0, 0.1) 0 4px 8px 0;

  --max-width: 1280px;
  --content-width: 1080px;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: "Inter", "Noto Sans JP", -apple-system, system-ui, "Helvetica Neue", sans-serif;
  color: var(--ink);
  background: var(--canvas);
  line-height: 1.6;
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: color 0.15s;
}

a:hover {
  color: var(--primary-active);
}

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

/* ── Header (top-nav: white, 80px, 1px bottom hairline) ── */
.header {
  background: var(--canvas);
  color: var(--ink);
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 1px solid var(--hairline);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 40px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 80px;
}

.logo {
  font-size: 1.25rem;     /* wordmark in Rausch */
  font-weight: 700;
  color: var(--primary);
  letter-spacing: -0.2px;
}

.nav-list {
  list-style: none;
  display: flex;
  gap: 28px;
}

.nav-list a {
  color: var(--ink);          /* nav-link 16px/600 */
  font-size: 1rem;
  font-weight: 600;
}

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

.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--ink);
  font-size: 1.5rem;
  cursor: pointer;
}

/* ── Hero (white canvas, ink headline modest weight, one Rausch CTA) ── */
.hero {
  background: var(--canvas);
  color: var(--ink);
  text-align: center;
  padding: 88px 24px 80px;
  border-bottom: 1px solid var(--hairline-soft);
}

.hero h1 {
  font-size: clamp(1.8rem, 4vw, 2.1rem);  /* ~29–34px, modest per Airbnb */
  font-weight: 700;
  line-height: 1.35;
  letter-spacing: -0.5px;
  max-width: 760px;
  margin: 0 auto 18px;
}

.hero h1 span {
  color: var(--primary);   /* the Rausch moment */
}

.hero p {
  font-size: 1.05rem;
  font-weight: 400;
  color: var(--body);
  line-height: 1.5;
  max-width: 660px;
  margin: 0 auto 32px;
}

/* button-primary: Rausch fill, white text, 8px radius, ~48px height, weight 500 */
.hero-cta,
.cta-btn {
  display: inline-block;
  background: var(--primary);
  color: var(--on-primary);
  font-weight: 500;
  font-size: 1rem;
  padding: 14px 28px;
  border-radius: var(--r-sm);
  transition: background 0.15s, transform 0.15s;
}

.hero-cta:hover,
.cta-btn:hover {
  background: var(--primary-active);
  color: var(--on-primary);
  transform: translateY(-1px);
}

.hero-photo {
  max-width: var(--content-width);
  margin: 48px auto 0;
  padding: 0 8px;
}

.hero-photo img {
  width: 100%;
  height: auto;
  border-radius: var(--r-md);
  box-shadow: var(--shadow);
  display: block;
}

.section-photo {
  max-width: var(--content-width);
  margin: 0 auto 44px;
}

.section-photo img {
  width: 100%;
  height: auto;
  max-height: 460px;
  object-fit: cover;
  border-radius: var(--r-md);
  box-shadow: var(--shadow);
  display: block;
}

/* ── Sections (64px band padding) ── */
.section {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 64px 40px;
}

.section-alt {
  max-width: none;
  background: var(--surface-soft);
}

.section-alt > * {
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
}

.section-title {
  font-size: 1.5rem;      /* ~24px, weight 600 (modest) */
  font-weight: 600;
  text-align: center;
  letter-spacing: -0.4px;
  margin-bottom: 10px;
  color: var(--ink);
}

.section-lead {
  text-align: center;
  color: var(--muted);
  margin-bottom: 44px;
  font-size: 1rem;
  font-weight: 400;
}

/* ── Cards (flat with hairline; one shadow tier on hover; 14px radius) ── */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.card {
  background: var(--canvas);
  border-radius: var(--r-md);
  padding: 32px 28px;
  border: 1px solid var(--hairline);
  transition: box-shadow 0.2s, transform 0.2s;
}

.card:hover {
  box-shadow: var(--shadow);
  transform: translateY(-2px);
}

.card-icon {
  margin-bottom: 16px;
  color: var(--primary);
  line-height: 0;
}

.card-icon svg {
  width: 36px;
  height: 36px;
}

.card h3 {
  font-size: 1.05rem;     /* title-md 16px/600 ≈ */
  font-weight: 600;
  margin-bottom: 10px;
  color: var(--ink);
}

.card p {
  font-size: 0.94rem;
  font-weight: 400;
  color: var(--body);
  line-height: 1.6;
}

/* ── Steps (ink badge, like date-selected; 14px radius cards) ── */
.steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
  counter-reset: step;
}

.step {
  background: var(--canvas);
  border-radius: var(--r-md);
  padding: 28px 24px;
  border: 1px solid var(--hairline);
  position: relative;
  text-align: center;
  transition: box-shadow 0.2s;
}

.step:hover {
  box-shadow: var(--shadow);
}

.step::before {
  counter-increment: step;
  content: "STEP " counter(step);
  display: inline-block;
  background: var(--ink);
  color: var(--on-primary);
  font-size: 0.7rem;
  font-weight: 600;
  padding: 5px 14px;
  border-radius: var(--r-full);
  margin-bottom: 16px;
  letter-spacing: 0.04em;
}

.step h3 {
  font-size: 1.02rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--ink);
}

.step p {
  font-size: 0.9rem;
  color: var(--body);
}

/* ── FAQ ── */
.faq-list {
  max-width: 780px;
  margin: 0 auto;
}

.faq-item {
  background: var(--canvas);
  border: 1px solid var(--hairline);
  border-radius: var(--r-md);
  margin-bottom: 12px;
  overflow: hidden;
}

.faq-question {
  width: 100%;
  background: none;
  border: none;
  padding: 22px 24px;
  font-size: 1rem;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: var(--ink);
  font-family: inherit;
  line-height: 1.5;
}

.faq-question::after {
  content: "+";
  font-size: 1.4rem;
  font-weight: 300;
  color: var(--ink);
  transition: transform 0.3s;
  flex-shrink: 0;
  margin-left: 16px;
}

.faq-item.open .faq-question::after {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease;
}

.faq-answer-inner {
  padding: 0 24px 22px;
  font-size: 0.95rem;
  color: var(--body);
  line-height: 1.65;
}

/* ── CTA Banner (surface-soft band, ink heading, one Rausch button — no gradient) ── */
.cta-banner {
  background: var(--surface-soft);
  color: var(--ink);
  text-align: center;
  padding: 64px 24px;
  border-top: 1px solid var(--hairline-soft);
  border-bottom: 1px solid var(--hairline-soft);
}

.cta-banner h2 {
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: -0.4px;
  margin-bottom: 12px;
}

.cta-banner p {
  font-size: 1rem;
  color: var(--body);
  margin-bottom: 28px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* ── Article ── */
.article-content {
  max-width: var(--content-width);
  margin: 0 auto;
}

.article-content h3 {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--ink);
  margin: 36px 0 12px;
  padding-left: 14px;
  border-left: 3px solid var(--primary);
}

.article-content p {
  margin-bottom: 16px;
  font-size: 1rem;
  font-weight: 400;
  color: var(--body);
}

.article-content ul {
  margin: 0 0 16px 22px;
  font-size: 0.96rem;
  color: var(--body);
}

.article-content li {
  margin-bottom: 8px;
}

.highlight-box {
  background: var(--surface-soft);
  border: 1px solid var(--hairline);
  border-left: 3px solid var(--primary);
  border-radius: var(--r-sm);
  padding: 20px 24px;
  margin: 24px 0;
  font-size: 0.96rem;
  color: var(--body);
}

.highlight-box strong {
  color: var(--ink);
}

/* ── Footer (footer-light: white canvas, ink text, hairline top) ── */
.footer {
  background: var(--canvas);
  color: var(--muted);
  text-align: center;
  padding: 40px 24px;
  font-size: 0.85rem;
  border-top: 1px solid var(--hairline);
}

.footer a {
  color: var(--ink);
  font-weight: 600;
}

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

/* ── Fade-in ── */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .header-inner {
    padding: 0 20px;
  }

  .hero {
    padding: 64px 22px 56px;
  }

  .section {
    padding: 56px 22px;
  }

  .nav-list {
    display: none;
    position: absolute;
    top: 80px;
    left: 0;
    right: 0;
    background: var(--canvas);
    flex-direction: column;
    padding: 16px 20px;
    gap: 14px;
    border-bottom: 1px solid var(--hairline);
    box-shadow: var(--shadow);
  }

  .nav-list.open {
    display: flex;
  }

  .nav-toggle {
    display: block;
  }

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

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