/* ===== IPFA Design System: "Silent Bridge" (静謐の橋) ===== */

/* --- Google Fonts --- */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;600;700&family=Noto+Sans+JP:wght@400;600;700&display=swap');

/* --- Design Tokens --- */
:root {
  /* Colors */
  --bg-light: #F5F3F0;
  --bg-dark: #1B2A4A;
  --text-primary: #2C2C2C;
  --text-on-dark: #FFFFFF;
  --accent: #856C3D;
  --accent-hover: #6F5A30;
  --sub-accent: #3D5A80;
  --card-bg: #FFFFFF;
  --card-shadow: rgba(0, 0, 0, 0.06);
  --border-light: rgba(0, 0, 0, 0.08);
  --border-dark: rgba(255, 255, 255, 0.12);

  /* Typography */
  --font-en: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-jp: 'Noto Sans JP', 'Hiragino Kaku Gothic Pro', 'Yu Gothic', sans-serif;
  --lh-en: 1.6;
  --lh-jp: 1.9;

  /* Layout */
  --max-width: 1140px;
  --text-width-jp: 680px;
  --text-width-en: 720px;
  --side-pad: 24px;
  --section-pad: 72px;

  /* Transitions */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --transition-fast: 150ms;
  --transition-normal: 200ms;
  --transition-slow: 300ms;
}

@media (min-width: 768px) {
  :root {
    --side-pad: 48px;
    --section-pad: 120px;
  }
}

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

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

body {
  font-family: var(--font-en);
  color: var(--text-primary);
  background: var(--bg-light);
  line-height: var(--lh-en);
  font-size: 17px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Japanese body override */
[lang="ja"] body,
.lang-ja {
  font-family: var(--font-jp), var(--font-en);
  line-height: var(--lh-jp);
  font-size: calc(17px * 0.92);
}

[lang="ja"] h1, [lang="ja"] h2, [lang="ja"] h3,
[lang="ja"] .hero-heading {
  font-family: var(--font-jp), var(--font-en);
}

img, video {
  max-width: 100%;
  display: block;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-fast) var(--ease-out);
}

ul, ol {
  list-style: none;
}

button, input, textarea {
  font: inherit;
  color: inherit;
  border: none;
  background: none;
}

/* --- Container --- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding-left: var(--side-pad);
  padding-right: var(--side-pad);
}

/* --- Section Base --- */
.section {
  padding-top: var(--section-pad);
  padding-bottom: var(--section-pad);
}

.section--light {
  background: var(--bg-light);
  color: var(--text-primary);
}

.section--dark {
  background: var(--bg-dark);
  color: var(--text-on-dark);
}

/* --- Category Labels --- */
.label {
  display: inline-block;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.15em;
  color: var(--accent);
  margin-bottom: 24px;
  text-transform: uppercase;
}

[lang="ja"] .label {
  text-transform: none;
  letter-spacing: 0.1em;
}

.label--dark {
  color: var(--accent);
}

/* --- Typography --- */
.hero-heading {
  font-size: clamp(40px, 5vw, 56px);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: 24px;
  font-family: var(--font-en);
}

[lang="ja"] .hero-heading {
  font-family: var(--font-jp), var(--font-en);
  letter-spacing: 0;
  line-height: 1.3;
}

.section-heading {
  font-size: clamp(28px, 3.5vw, 40px);
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 20px;
}

.subtext {
  font-size: 18px;
  line-height: 1.7;
  max-width: var(--text-width-en);
  opacity: 0.85;
}

[lang="ja"] .subtext {
  max-width: var(--text-width-jp);
  font-size: calc(18px * 0.92);
  line-height: var(--lh-jp);
}

.lead-text {
  font-size: clamp(24px, 3vw, 36px);
  font-weight: 400;
  line-height: 1.6;
  max-width: 900px;
}

[lang="ja"] .lead-text {
  line-height: 1.8;
  font-size: clamp(22px, 2.8vw, 34px);
}

/* --- CTA Button --- */
.cta-btn {
  display: inline-block;
  padding: 14px 36px;
  background: var(--accent);
  color: #FFFFFF;
  font-size: 15px;
  font-weight: 600;
  border-radius: 100px;
  cursor: pointer;
  transition: background var(--transition-normal) var(--ease-out),
              transform var(--transition-normal) var(--ease-out);
  border: none;
  text-decoration: none;
}

.cta-btn:hover {
  background: var(--accent-hover);
}

.cta-btn:active {
  transform: scale(0.98);
}

.cta-btn--outline {
  background: transparent;
  border: 1.5px solid var(--accent);
  color: var(--accent);
}

.cta-btn--outline:hover {
  background: var(--accent);
  color: #FFFFFF;
}

/* --- Navigation --- */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(245, 243, 240, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  transition: background var(--transition-slow) var(--ease-out),
              box-shadow var(--transition-slow) var(--ease-out);
}

.nav--scrolled {
  box-shadow: 0 1px 0 rgba(0, 0, 0, 0.06);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--side-pad);
}

.nav__logo {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--text-primary);
  text-decoration: none;
  font-family: var(--font-en);
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav__link {
  font-size: 14px;
  font-weight: 500;
  color: var(--text-primary);
  text-decoration: none;
  transition: color var(--transition-fast) var(--ease-out);
  position: relative;
}

.nav__link:hover {
  color: var(--accent);
}

.nav__link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 1.5px;
  background: var(--accent);
  transition: width var(--transition-fast) var(--ease-out);
}

.nav__link:hover::after {
  width: 100%;
}

.nav__contact {
  padding: 8px 22px;
  font-size: 13px;
  font-weight: 600;
  background: var(--accent);
  color: #FFFFFF;
  border-radius: 100px;
  text-decoration: none;
  transition: background var(--transition-normal) var(--ease-out);
}

.nav__contact:hover {
  background: var(--accent-hover);
}

.nav__lang {
  font-size: 13px;
  font-weight: 500;
  color: var(--text-primary);
  opacity: 0.6;
  text-decoration: none;
  transition: opacity var(--transition-fast) var(--ease-out);
}

.nav__lang:hover,
.nav__lang--active {
  opacity: 1;
}

.nav__lang-separator {
  font-size: 13px;
  opacity: 0.3;
  margin: 0 4px;
}

/* Mobile Nav */
.nav__hamburger {
  display: none;
  width: 44px;
  height: 44px;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 0;
}

.nav__hamburger span {
  display: block;
  width: 22px;
  height: 1.5px;
  background: var(--text-primary);
  transition: transform var(--transition-normal) var(--ease-out),
              opacity var(--transition-normal) var(--ease-out);
}

.nav__hamburger.active span:first-child {
  transform: translateY(6.5px) rotate(45deg);
}

.nav__hamburger.active span:nth-child(2) {
  opacity: 0;
}

.nav__hamburger.active span:last-child {
  transform: translateY(-6.5px) rotate(-45deg);
}

@media (max-width: 767px) {
  .nav {
    overflow: hidden;
  }

  .nav__hamburger {
    display: flex;
  }

  .nav__links {
    position: fixed;
    top: 72px;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--bg-light);
    flex-direction: column;
    align-items: flex-start;
    justify-content: flex-start;
    padding: 40px var(--side-pad);
    gap: 28px;
    transform: translateX(100%);
    transition: transform var(--transition-slow) var(--ease-out);
  }

  .nav__links.open {
    transform: translateX(0);
  }

  .nav__link {
    font-size: 18px;
  }

  .nav__link::after {
    display: none;
  }
}

/* --- Card Grid --- */
.card-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  margin-top: 48px;
}

@media (min-width: 768px) {
  .card-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
  }
}

.card {
  background: var(--card-bg);
  border-radius: 8px;
  padding: 36px 32px;
  box-shadow: 0 2px 12px var(--card-shadow);
  transition: box-shadow var(--transition-normal) var(--ease-out),
              transform var(--transition-normal) var(--ease-out);
}

.card:hover {
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.1);
  transform: translateY(-2px);
}

.section--dark .card {
  background: rgba(255, 255, 255, 0.06);
  box-shadow: none;
  border: 1px solid rgba(255, 255, 255, 0.08);
}

.section--dark .card:hover {
  background: rgba(255, 255, 255, 0.1);
  box-shadow: none;
  transform: translateY(-2px);
}

.card__title {
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 12px;
  line-height: 1.4;
}

.card__text {
  font-size: 15px;
  line-height: 1.7;
  opacity: 0.8;
}

[lang="ja"] .card__text {
  line-height: 1.85;
  font-size: calc(15px * 0.92);
}

/* Card number decoration */
.card__number {
  font-size: 48px;
  font-weight: 700;
  color: var(--accent);
  opacity: 0.18;
  line-height: 1;
  margin-bottom: 20px;
  font-family: var(--font-en);
}

/* --- Hero Section --- */
.hero {
  min-height: 70vh;
  display: flex;
  align-items: center;
  padding-top: calc(var(--section-pad) + 72px);
  padding-bottom: var(--section-pad);
}

.hero__content {
  max-width: 780px;
}

/* --- News Cards --- */
.news-card {
  padding: 28px 0;
  border-bottom: 1px solid var(--border-light);
  transition: padding-left var(--transition-normal) var(--ease-out);
}

.news-card:first-child {
  border-top: 1px solid var(--border-light);
}

.news-card:hover {
  padding-left: 8px;
}

.news-card__date {
  font-size: 13px;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 8px;
  font-family: var(--font-en);
}

.news-card__title {
  font-size: 17px;
  font-weight: 500;
  line-height: 1.6;
}

[lang="ja"] .news-card__title {
  font-size: calc(17px * 0.92);
  line-height: 1.8;
}

/* --- Newsletter --- */
.newsletter {
  border-top: 1px solid var(--border-light);
}

.newsletter__form {
  display: flex;
  gap: 12px;
  margin-top: 24px;
  max-width: 500px;
}

.newsletter__input {
  flex: 1;
  padding: 12px 20px;
  border: 1.5px solid rgba(0, 0, 0, 0.15);
  border-radius: 100px;
  font-size: 15px;
  background: #FFFFFF;
  transition: border-color var(--transition-fast) var(--ease-out);
}

.newsletter__input:focus {
  outline: none;
  border-color: var(--accent);
}

.newsletter__input::placeholder {
  color: rgba(0, 0, 0, 0.35);
}

@media (max-width: 480px) {
  .newsletter__form {
    flex-direction: column;
  }
}

/* --- Footer --- */
.footer {
  padding-top: 80px;
  padding-bottom: 40px;
  background: var(--bg-light);
}

.footer__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
  margin-bottom: 60px;
}

@media (min-width: 768px) {
  .footer__grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

.footer__col-title {
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 20px;
  color: var(--text-primary);
}

[lang="ja"] .footer__col-title {
  text-transform: none;
  letter-spacing: 0.05em;
  font-size: 14px;
}

.footer__link {
  display: block;
  font-size: 14px;
  color: var(--text-primary);
  opacity: 0.6;
  margin-bottom: 10px;
  transition: opacity var(--transition-fast) var(--ease-out);
  text-decoration: none;
}

.footer__link:hover {
  opacity: 1;
}

.footer__bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 24px;
  border-top: 1px solid var(--border-light);
  flex-wrap: wrap;
  gap: 12px;
}

.footer__copyright {
  font-size: 13px;
  opacity: 0.5;
}

.footer__legal {
  font-size: 13px;
  opacity: 0.5;
  text-decoration: none;
  transition: opacity var(--transition-fast) var(--ease-out);
}

.footer__legal:hover {
  opacity: 0.8;
}

/* --- Fade-in Animation --- */
.fade-in {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity var(--transition-slow) var(--ease-out),
              transform var(--transition-slow) var(--ease-out);
}

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

/* --- About Page --- */
.about-hero {
  padding-top: calc(var(--section-pad) + 72px);
  padding-bottom: var(--section-pad);
}

.features-list {
  display: grid;
  gap: 48px;
  margin-top: 48px;
}

.feature-item {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

@media (min-width: 768px) {
  .feature-item {
    grid-template-columns: 200px 1fr;
    gap: 48px;
  }
}

.feature-item__title {
  font-size: 18px;
  font-weight: 700;
  color: var(--accent);
}

.feature-item__text {
  font-size: 16px;
  line-height: 1.8;
  opacity: 0.85;
}

[lang="ja"] .feature-item__text {
  line-height: var(--lh-jp);
  font-size: calc(16px * 0.92);
}

/* Team cards */
.team-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  margin-top: 48px;
}

@media (min-width: 768px) {
  .team-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
  }
}

.team-card {
  text-align: center;
  padding: 48px 32px;
  background: var(--card-bg);
  border-radius: 8px;
  box-shadow: 0 2px 12px var(--card-shadow);
}

.team-card__avatar {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background: var(--bg-dark);
  margin: 0 auto 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-on-dark);
  font-size: 28px;
  font-weight: 700;
  font-family: var(--font-en);
}

.team-card__role {
  font-size: 12px;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.1em;
  margin-bottom: 8px;
}

.team-card__name {
  font-size: 18px;
  font-weight: 700;
}

.team-card__bio {
  font-size: 14px;
  opacity: 0.65;
  margin-top: 8px;
  line-height: 1.6;
}

/* --- Programs Page --- */
.program-section {
  padding-top: 80px;
  padding-bottom: 80px;
}

.program-section + .program-section {
  border-top: 1px solid var(--border-light);
}

.section--dark .program-section + .program-section {
  border-top-color: var(--border-dark);
}

.program-bullets {
  margin-top: 24px;
  display: grid;
  gap: 12px;
}

.program-bullet {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  font-size: 16px;
  line-height: 1.7;
}

[lang="ja"] .program-bullet {
  font-size: calc(16px * 0.92);
  line-height: 1.85;
}

.program-bullet::before {
  content: '';
  flex-shrink: 0;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  margin-top: 9px;
}

.section--dark .program-bullet::before {
  background: var(--accent);
}

.program-number {
  font-size: 72px;
  font-weight: 700;
  color: var(--accent);
  opacity: 0.15;
  line-height: 1;
  margin-bottom: 16px;
  font-family: var(--font-en);
}

.section--dark .program-number {
  color: var(--accent);
  opacity: 0.3;
}

.program-title {
  font-size: clamp(24px, 3vw, 32px);
  font-weight: 700;
  margin-bottom: 16px;
  line-height: 1.3;
}

.program-desc {
  font-size: 17px;
  line-height: 1.7;
  max-width: 720px;
  opacity: 0.85;
}

[lang="ja"] .program-desc {
  font-size: calc(17px * 0.92);
  line-height: var(--lh-jp);
  max-width: var(--text-width-jp);
}

/* --- Contact Page --- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 60px;
  margin-top: 48px;
}

@media (min-width: 768px) {
  .contact-grid {
    grid-template-columns: 1fr 1fr;
    gap: 80px;
  }
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.form-label {
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.05em;
}

.form-input,
.form-textarea {
  padding: 14px 18px;
  border: 1.5px solid rgba(0, 0, 0, 0.12);
  border-radius: 8px;
  font-size: 16px;
  background: #FFFFFF;
  transition: border-color var(--transition-fast) var(--ease-out);
}

.form-input:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--accent);
}

.form-textarea {
  min-height: 140px;
  resize: vertical;
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.contact-info__item {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.contact-info__label {
  font-size: 12px;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

[lang="ja"] .contact-info__label {
  text-transform: none;
}

.contact-info__value {
  font-size: 17px;
  line-height: 1.6;
}

.contact-info__value a {
  color: var(--sub-accent);
  text-decoration: underline;
  text-decoration-color: transparent;
  transition: text-decoration-color var(--transition-fast) var(--ease-out);
}

.contact-info__value a:hover {
  text-decoration-color: var(--sub-accent);
}

/* --- Utility --- */
.text-center { text-align: center; }
.mt-16 { margin-top: 16px; }
.mt-24 { margin-top: 24px; }
.mt-32 { margin-top: 32px; }
.mt-48 { margin-top: 48px; }
.mb-0 { margin-bottom: 0; }
.max-w-text { max-width: 680px; }
.max-w-text-en { max-width: 720px; }
.mx-auto { margin-left: auto; margin-right: auto; }

/* --- Program Case Study Block --- */
.program-case {
  border-left: 3px solid var(--accent);
  padding-left: 24px;
  margin-top: 48px;
}
.program-case__text {
  font-size: 15px;
  line-height: 1.8;
  color: rgba(255, 255, 255, 0.85);
  max-width: 720px;
}
.section--light .program-case__text {
  color: var(--text-primary);
  opacity: 0.85;
}

/* --- Leadership Cards --- */
.leadership-list {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin-top: 48px;
}
.leader-card {
  background: rgba(255,255,255,0.04);
  border-bottom: 1px solid rgba(255,255,255,0.08);
  padding: 0;
}
.leader-card__header {
  display: flex;
  align-items: center;
  gap: 20px;
  padding: 24px 0;
  cursor: pointer;
}
.leader-card__avatar {
  width: 52px;
  height: 52px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  font-weight: 700;
  flex-shrink: 0;
}
.leader-card__info {
  flex: 1;
}
.leader-card__role {
  font-size: 12px;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.05em;
  margin-bottom: 4px;
}
.leader-card__name {
  font-size: 20px;
  font-weight: 700;
  color: #fff;
  line-height: 1.3;
}
.leader-card__name-en {
  font-size: 14px;
  font-weight: 400;
  color: rgba(255,255,255,0.5);
  margin-top: 2px;
}
.leader-card__toggle {
  background: none;
  border: 1px solid rgba(255,255,255,0.2);
  color: rgba(255,255,255,0.5);
  width: 36px;
  height: 36px;
  border-radius: 50%;
  font-size: 18px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: all 200ms ease;
}
.leader-card__toggle:hover {
  border-color: var(--accent);
  color: var(--accent);
}
.leader-card__toggle[aria-expanded="true"] {
  transform: rotate(45deg);
  border-color: var(--accent);
  color: var(--accent);
}
.leader-card__bio {
  padding: 0 0 24px 72px;
  max-width: 680px;
}
.leader-card__bio p {
  font-size: 15px;
  line-height: 1.85;
  color: rgba(255,255,255,0.75);
  margin: 0;
}
.leader-card--advisor {
  margin-top: 24px;
  border-top: 1px solid rgba(255,255,255,0.08);
}
@media (max-width: 768px) {
  .leader-card__bio {
    padding-left: 0;
  }
  .leader-card__name {
    font-size: 18px;
  }
}

/* --- Beliefs Section --- */
.beliefs-list {
  display: flex;
  flex-direction: column;
  gap: 0;
  margin-top: 48px;
  max-width: 680px;
}
.belief-item {
  padding: 28px 0;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}
.belief-item:first-child {
  border-top: 1px solid rgba(255,255,255,0.08);
}
.belief-item__title {
  font-size: 18px;
  font-weight: 700;
  color: #fff;
  margin-bottom: 8px;
}
.belief-item__text {
  font-size: 15px;
  line-height: 1.85;
  color: rgba(255,255,255,0.7);
}