/* ============================================================
   Base & Reset
   ============================================================ */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-base);
  font-size: var(--text-base);
  font-weight: var(--weight-regular);
  line-height: var(--leading-normal);
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

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

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

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

ul, ol {
  list-style: none;
}

button {
  cursor: pointer;
  border: none;
  background: none;
  font-family: inherit;
}

input, textarea, select {
  font-family: inherit;
  font-size: var(--text-base);
}

/* ============================================================
   Layout Utilities
   ============================================================ */
.container {
  width: 100%;
  max-width: var(--container-xl);
  margin-inline: auto;
  padding-inline: var(--container-px);
}

.container--sm { max-width: var(--container-sm); }
.container--md { max-width: var(--container-md); }
.container--lg { max-width: var(--container-lg); }

.section {
  padding-block: var(--section-py-sm);
}

@media (min-width: 768px) {
  :root {
    --container-px: 2rem;
    --section-py-sm: 4rem;
  }
  .section {
    padding-block: var(--section-py);
  }
}

@media (min-width: 1024px) {
  :root {
    --container-px: 3rem;
  }
}

/* Section Background Variants */
.section--white  { background-color: var(--color-white); }
.section--gray   { background-color: var(--color-bg-gray); }
.section--blue   { background-color: var(--color-bg-blue); }
.section--navy   { background-color: var(--color-navy); color: var(--color-white); }
.section--orange { background-color: var(--color-primary); color: var(--color-white); }
.section--warm   { background-color: var(--color-primary-bg); }

/* ============================================================
   Section Header (共通見出し)
   ============================================================ */
.section-header {
  text-align: center;
  margin-bottom: var(--space-10);
}

.section-header--left {
  text-align: left;
}

.section-label {
  display: inline-block;
  font-family: var(--font-en);
  font-size: var(--text-xs);
  font-weight: var(--weight-bold);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-primary);
  background-color: var(--color-primary-bg);
  padding: var(--space-1) var(--space-4);
  border-radius: var(--radius-full);
  margin-bottom: var(--space-4);
}

.section--navy .section-label,
.section--orange .section-label {
  color: var(--color-yellow);
  background-color: rgba(255,255,255,.15);
}

.section-title {
  font-size: var(--text-2xl);
  font-weight: var(--weight-bold);
  line-height: var(--leading-tight);
  color: var(--color-navy);
  margin-bottom: var(--space-4);
}

.section--navy .section-title,
.section--orange .section-title {
  color: var(--color-white);
}

.section-subtitle {
  font-size: var(--text-base);
  color: var(--color-text-sub);
  line-height: var(--leading-loose);
  max-width: 540px;
  margin-inline: auto;
}

.section--navy .section-subtitle,
.section--orange .section-subtitle {
  color: rgba(255,255,255,.8);
}

@media (min-width: 768px) {
  .section-title { font-size: var(--text-3xl); }
  .section-header { margin-bottom: var(--space-16); }
}

/* ============================================================
   Buttons
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  font-family: var(--font-base);
  font-size: var(--text-base);
  font-weight: var(--weight-bold);
  line-height: 1;
  text-decoration: none;
  border-radius: var(--radius-full);
  padding: 1em 2em;
  border: 2px solid transparent;
  transition: all var(--transition-base);
  cursor: pointer;
  white-space: nowrap;
}

.btn--primary {
  background-color: var(--color-primary);
  color: var(--color-white);
  box-shadow: var(--shadow-green);
}

.btn--primary:hover {
  background-color: var(--color-primary-dark);
  color: var(--color-white);
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(26,138,74,.35);
}

.btn--outline {
  background-color: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn--outline:hover {
  background-color: var(--color-primary);
  color: var(--color-white);
}

.btn--white {
  background-color: var(--color-white);
  color: var(--color-primary);
  box-shadow: var(--shadow-md);
}

.btn--white:hover {
  background-color: var(--color-primary-bg);
  color: var(--color-primary);
}

.btn--navy {
  background-color: var(--color-navy);
  color: var(--color-white);
}

.btn--navy:hover {
  background-color: var(--color-navy-dark);
  color: var(--color-white);
}

.btn--lg {
  font-size: var(--text-md);
  padding: 1.1em 2.5em;
}

.btn--xl {
  font-size: var(--text-lg);
  padding: 1.1em 3em;
}

.btn--sm {
  font-size: var(--text-sm);
  padding: 0.75em 1.5em;
}

.btn--full { width: 100%; }

.btn__arrow {
  font-size: 1.1em;
  transition: transform var(--transition-base);
}

.btn:hover .btn__arrow {
  transform: translateX(3px);
}

/* ============================================================
   Card Base
   ============================================================ */
.card {
  background-color: var(--color-white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  overflow: hidden;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.card__img {
  aspect-ratio: 16/9;
  overflow: hidden;
}

.card__img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-slow);
}

.card:hover .card__img img {
  transform: scale(1.04);
}

.card__body {
  padding: var(--space-6);
}

.card__tag {
  display: inline-block;
  font-size: var(--text-xs);
  font-weight: var(--weight-bold);
  padding: 0.25em 0.75em;
  border-radius: var(--radius-full);
  background-color: var(--color-primary-bg);
  color: var(--color-primary);
  margin-bottom: var(--space-3);
}

.card__title {
  font-size: var(--text-md);
  font-weight: var(--weight-bold);
  line-height: var(--leading-tight);
  color: var(--color-navy);
  margin-bottom: var(--space-3);
}

.card__text {
  font-size: var(--text-sm);
  color: var(--color-text-sub);
  line-height: var(--leading-normal);
}

/* ============================================================
   Grid Helpers
   ============================================================ */
.grid {
  display: grid;
  gap: var(--space-6);
}

.grid--2 { grid-template-columns: 1fr; }
.grid--3 { grid-template-columns: 1fr; }
.grid--4 { grid-template-columns: 1fr; }

@media (min-width: 640px) {
  .grid--2 { grid-template-columns: repeat(2, 1fr); }
  .grid--4 { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 768px) {
  .grid--3 { grid-template-columns: repeat(3, 1fr); }
}

@media (min-width: 1024px) {
  .grid--4 { grid-template-columns: repeat(4, 1fr); }
}

/* ============================================================
   Animation Classes (JS-driven)
   ============================================================ */
.fade-up {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

.fade-in {
  opacity: 0;
  transition: opacity 0.6s ease;
}

.fade-in.is-visible {
  opacity: 1;
}

/* Staggered children */
.stagger-children > * {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.stagger-children.is-visible > *:nth-child(1) { transition-delay: 0s; }
.stagger-children.is-visible > *:nth-child(2) { transition-delay: 0.1s; }
.stagger-children.is-visible > *:nth-child(3) { transition-delay: 0.2s; }
.stagger-children.is-visible > *:nth-child(4) { transition-delay: 0.3s; }
.stagger-children.is-visible > *:nth-child(5) { transition-delay: 0.4s; }
.stagger-children.is-visible > *:nth-child(6) { transition-delay: 0.5s; }

.stagger-children.is-visible > * {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================================
   Accessibility
   ============================================================ */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 3px;
}