:root {
  color-scheme: light;
  --ink: #17312e;
  --ink-soft: #4d615e;
  --brand: #176b65;
  --brand-deep: #0f554f;
  --brand-pale: #dcece8;
  --paper: #fbfcfa;
  --white: #ffffff;
  --line: #c7d9d5;
  --focus: #d46a3a;
  --shadow: 0 16px 42px rgba(23, 49, 46, 0.09);
  font-family: "Yu Gothic UI", "Yu Gothic", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  font-size: 18px;
}

* {
  box-sizing: border-box;
}

html {
  background: var(--paper);
  scroll-behavior: smooth;
}

body {
  min-width: 320px;
  margin: 0;
  color: var(--ink);
  background:
    linear-gradient(180deg, rgba(220, 236, 232, 0.6) 0, rgba(220, 236, 232, 0) 280px),
    var(--paper);
  font-size: 1rem;
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}

.site-header {
  border-bottom: 1px solid rgba(23, 107, 101, 0.15);
  background: rgba(251, 252, 250, 0.92);
}

.site-header__inner {
  display: flex;
  width: min(1080px, calc(100% - 40px));
  min-height: 80px;
  margin: 0 auto;
  align-items: center;
  gap: 13px;
}

.brand-mark {
  display: block;
  flex: 0 0 auto;
}

.brand-name {
  margin: 0;
  color: var(--brand-deep);
  font-family: "BIZ UDPGothic", "Yu Gothic UI", sans-serif;
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

main {
  width: min(1080px, calc(100% - 40px));
  margin: 0 auto;
  padding: 64px 0 96px;
}

.intro {
  max-width: 800px;
  margin: 0 auto 48px;
  text-align: center;
}

h1,
h2 {
  margin: 0;
  font-family: "BIZ UDPGothic", "Yu Gothic UI", sans-serif;
  line-height: 1.35;
}

h1 {
  font-size: clamp(2.15rem, 6vw, 3.55rem);
  letter-spacing: 0.03em;
}

.intro__lead {
  margin: 22px 0 0;
  color: var(--ink-soft);
  font-size: clamp(1rem, 2.3vw, 1.14rem);
  font-weight: 500;
  line-height: 1.9;
}

.guide-options {
  display: grid;
  grid-template-columns: minmax(0, 1.45fr) minmax(320px, 0.75fr);
  gap: 28px;
  align-items: start;
}

.guide-card {
  position: relative;
  overflow: hidden;
  padding: 36px;
  border: 1px solid var(--line);
  border-radius: 22px;
  background: var(--white);
  box-shadow: var(--shadow);
}

.guide-card::before {
  position: absolute;
  inset: 0 auto 0 0;
  width: 8px;
  background: var(--brand);
  content: "";
}

.guide-card--pdf {
  display: flex;
  flex-direction: column;
  background: #f3f8f6;
}

.guide-card--pdf::before {
  background: #4d8e88;
}

.guide-card__heading {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
}

h2 {
  font-size: clamp(1.55rem, 3vw, 2rem);
  letter-spacing: 0.02em;
}

.guide-card__description {
  margin: 16px 0 24px;
  color: var(--ink-soft);
  font-size: 1rem;
  line-height: 1.75;
}

.video-frame {
  position: relative;
  overflow: hidden;
  width: 100%;
  border-radius: 14px;
  background: #102623;
  aspect-ratio: 16 / 9;
}

.video-frame iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.pdf-button {
  display: flex;
  width: 100%;
  min-height: 58px;
  margin-top: 20px;
  padding: 14px 17px;
  align-items: center;
  gap: 12px;
  border: 2px solid var(--brand);
  border-radius: 13px;
  color: var(--white);
  background: var(--brand);
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.45;
  text-decoration: none;
  transition: background-color 160ms ease, border-color 160ms ease, transform 160ms ease;
}

.pdf-button svg {
  flex: 0 0 auto;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.pdf-button__arrow {
  margin-left: auto;
}

.pdf-button:hover {
  border-color: var(--brand-deep);
  background: var(--brand-deep);
  transform: translateY(-1px);
}

.pdf-button:focus-visible,
iframe:focus-visible {
  outline: 4px solid var(--focus);
  outline-offset: 4px;
}

@media (max-width: 820px) {
  main {
    padding-top: 48px;
  }

  .guide-options {
    grid-template-columns: 1fr;
  }

}

@media (max-width: 520px) {
  :root {
    font-size: 18px;
  }

  .site-header__inner,
  main {
    width: min(100% - 28px, 1080px);
  }

  .site-header__inner {
    min-height: 72px;
  }

  .brand-mark {
    width: 42px;
    height: 42px;
  }

  main {
    padding: 40px 0 64px;
  }

  .intro {
    margin-bottom: 34px;
    text-align: left;
  }

  h1 {
    font-size: 2.25rem;
  }

  .intro__lead {
    margin-top: 18px;
    line-height: 1.8;
  }

  .lead-break {
    display: none;
  }

  .guide-options {
    gap: 20px;
  }

  .guide-card {
    padding: 27px 22px 24px 27px;
    border-radius: 18px;
  }

  .guide-card::before {
    width: 6px;
  }

  .guide-card__heading {
    align-items: center;
  }

  .guide-card__description {
    margin: 13px 0 21px;
  }

  .video-frame {
    border-radius: 11px;
  }

  .pdf-button {
    min-height: 60px;
  }
}

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

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}