/* ========================================
   Variables & Reset
   ======================================== */
:root {
  --navy-900: #0f1050;
  --navy-800: #141660;
  --navy-700: #191970;
  --navy-600: #2528a0;
  --navy-500: #3538b8;
  --navy-400: #5558c8;
  --navy-100: #eaeaf5;
  --navy-50: #f2f2fa;
  --white: #ffffff;
  --text: #1a1a2e;
  --text-muted: #5c5c7a;
  --border: #d8d8ea;
  --accent: #c9a227;
  --shadow: 0 4px 24px rgba(25, 25, 112, 0.08);
  --shadow-lg: 0 12px 40px rgba(25, 25, 112, 0.12);
  --radius: 12px;
  --radius-sm: 8px;
  --header-height: 72px;
  --transition: 0.25s ease;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--header-height);
}

body {
  font-family: "Noto Sans JP", sans-serif;
  font-size: 16px;
  line-height: 1.75;
  color: var(--text);
  background: var(--white);
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--navy-600);
  text-decoration: none;
  transition: color var(--transition);
}

a:hover {
  color: var(--navy-500);
}

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

ul {
  list-style: none;
}

.container {
  width: min(1120px, 100% - 48px);
  margin-inline: auto;
}

/* ========================================
   Buttons
   ======================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 28px;
  font-size: 0.9375rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  border: 2px solid transparent;
  cursor: pointer;
  transition: background var(--transition), color var(--transition), border-color var(--transition), transform var(--transition);
}

.btn:hover {
  transform: translateY(-1px);
}

.btn--primary {
  background: var(--navy-700);
  color: var(--white);
  border-color: var(--navy-700);
}

.btn--primary:hover {
  background: var(--navy-600);
  border-color: var(--navy-600);
  color: var(--white);
}

.btn--outline {
  background: transparent;
  color: var(--white);
  border-color: rgba(255, 255, 255, 0.6);
}

.btn--outline:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: var(--white);
  color: var(--white);
}

.section .btn--outline {
  color: var(--navy-700);
  border-color: var(--navy-700);
}

.section .btn--outline:hover {
  background: var(--navy-50);
  color: var(--navy-700);
}

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

/* ========================================
   Header
   ======================================== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--header-height);
  background: rgba(25, 25, 112, 0.94);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  width: min(1120px, 100% - 48px);
  margin-inline: auto;
}

.header__logo {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--white);
  letter-spacing: 0.04em;
}

.header__logo:hover {
  color: var(--white);
  opacity: 0.9;
}

.header__list {
  display: flex;
  gap: 32px;
}

.header__list a {
  font-size: 0.875rem;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.85);
}

.header__list a:hover {
  color: var(--white);
}

.header__toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.header__toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--white);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

.header__toggle.is-open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.header__toggle.is-open span:nth-child(2) {
  opacity: 0;
}

.header__toggle.is-open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ========================================
   Hero
   ======================================== */
.hero {
  position: relative;
  min-height: auto;
  display: flex;
  align-items: center;
  padding-top: var(--header-height);
  overflow: hidden;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.hero__bg {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(120deg, rgba(15, 16, 80, 0.97) 0%, rgba(25, 25, 112, 0.95) 45%, rgba(45, 48, 140, 0.9) 100%),
    radial-gradient(ellipse 80% 60% at 90% 20%, rgba(85, 88, 200, 0.35) 0%, transparent 55%),
    radial-gradient(ellipse 50% 40% at 10% 90%, rgba(201, 162, 39, 0.12) 0%, transparent 50%);
  background-color: var(--navy-700);
}

.hero__bg::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.04) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.5) 0%, transparent 85%);
}

.hero__orb {
  position: absolute;
  border-radius: 50%;
  pointer-events: none;
}

.hero__orb--1 {
  width: min(360px, 45vw);
  height: min(360px, 45vw);
  top: -80px;
  right: -60px;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.06) 0%, transparent 68%);
}

.hero__orb--2 {
  width: min(240px, 30vw);
  height: min(240px, 30vw);
  bottom: -60px;
  left: 35%;
  background: radial-gradient(circle, rgba(201, 162, 39, 0.14) 0%, transparent 70%);
}

.hero__inner {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 48px;
  padding-block: 48px 52px;
}

.hero__content {
  max-width: 580px;
}

.hero__label {
  display: inline-block;
  font-size: 0.6875rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 16px;
  padding: 6px 14px;
  border: 1px solid rgba(201, 162, 39, 0.45);
  border-radius: 999px;
  background: rgba(201, 162, 39, 0.1);
}

.hero__title {
  font-size: clamp(1.875rem, 4vw, 2.75rem);
  font-weight: 700;
  color: var(--white);
  line-height: 1.25;
  letter-spacing: 0.06em;
  margin-bottom: 16px;
  text-shadow: 0 2px 20px rgba(0, 0, 0, 0.25);
}

.hero__title::after {
  content: "";
  display: block;
  width: 48px;
  height: 3px;
  margin-top: 16px;
  background: linear-gradient(90deg, var(--accent), rgba(201, 162, 39, 0.3));
  border-radius: 2px;
}

.hero__lead {
  max-width: 520px;
  font-size: clamp(0.9375rem, 1.5vw, 1.0625rem);
  color: rgba(255, 255, 255, 0.88);
  margin-bottom: 32px;
  line-height: 1.8;
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.hero__actions .btn {
  font-weight: 700;
  padding: 14px 28px;
  font-size: 0.9375rem;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.25);
}

.hero__actions .btn--primary {
  background: var(--white);
  color: var(--navy-700);
  border-color: var(--white);
}

.hero__actions .btn--primary:hover {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--navy-900);
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.3);
}

.hero__actions .btn--outline {
  background: rgba(255, 255, 255, 0.14);
  color: var(--white);
  border-color: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(6px);
}

.hero__actions .btn--outline:hover {
  background: var(--white);
  color: var(--navy-700);
  border-color: var(--white);
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.3);
}

@media (max-width: 768px) {
  .hero__inner {
    grid-template-columns: 1fr;
    gap: 0;
    padding-block: 40px 44px;
  }

  .hero__visual {
    display: none;
  }
}

/* ========================================
   Sections
   ======================================== */
.section {
  padding-block: 96px;
}

.section--alt {
  background: var(--navy-50);
}

.section__header {
  margin-bottom: 48px;
}

.section__label {
  display: block;
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--navy-500);
  margin-bottom: 8px;
}

.section__title {
  font-size: clamp(1.75rem, 4vw, 2.25rem);
  font-weight: 700;
  color: var(--navy-800);
  margin-bottom: 16px;
}

.section__desc {
  max-width: 640px;
  color: var(--text-muted);
}

/* ========================================
   Basic Info
   ======================================== */
.info-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.info-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px 28px;
  box-shadow: var(--shadow);
}

.section--alt .info-card,
.section:not(.section--alt) .info-card {
  background: var(--white);
}

.info-card--wide {
  grid-column: 1 / -1;
}

.info-card dt {
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--navy-500);
  margin-bottom: 8px;
}

.info-card dd {
  font-size: 1rem;
  font-weight: 500;
  color: var(--text);
}

/* ========================================
   Overview
   ======================================== */
.overview-block {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 40px;
  margin-bottom: 32px;
  box-shadow: var(--shadow);
}

.overview-block:last-child {
  margin-bottom: 0;
}

.overview-block__title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--navy-800);
  padding-bottom: 16px;
  margin-bottom: 24px;
  border-bottom: 2px solid var(--navy-100);
}

.overview-block__body p {
  color: var(--text-muted);
  margin-bottom: 16px;
}

.check-list li {
  position: relative;
  padding-left: 28px;
  margin-bottom: 12px;
  color: var(--text);
}

.check-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 8px;
  height: 8px;
  background: var(--navy-500);
  border-radius: 50%;
}

.overview-block--rules .overview-block__body {
  display: flex;
  justify-content: center;
  padding-block: 8px;
}

.btn--download {
  gap: 10px;
  padding: 18px 32px;
  font-size: 1rem;
}

.btn__icon {
  flex-shrink: 0;
}

.officers-term {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 20px !important;
}

.table-wrap {
  overflow-x: auto;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}

.officers-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9375rem;
}

.officers-table th,
.officers-table td {
  padding: 16px 20px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

.officers-table th {
  background: var(--navy-800);
  color: var(--white);
  font-weight: 500;
  font-size: 0.8125rem;
  white-space: nowrap;
}

.officers-table tbody tr:last-child td {
  border-bottom: none;
}

.officers-table tbody tr:hover {
  background: var(--navy-50);
}

.officers-table td:first-child {
  font-weight: 500;
  color: var(--navy-700);
  white-space: nowrap;
}

/* ========================================
   Conference
   ======================================== */
.conference-card {
  background: linear-gradient(135deg, var(--navy-800) 0%, var(--navy-600) 100%);
  border-radius: var(--radius);
  padding: 48px;
  color: var(--white);
  margin-bottom: 48px;
  box-shadow: var(--shadow-lg);
}

.conference-card__badge {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  background: var(--accent);
  color: var(--navy-900);
  padding: 6px 14px;
  border-radius: 999px;
  margin-bottom: 20px;
}

.conference-card__title {
  font-size: clamp(1.375rem, 3vw, 1.75rem);
  font-weight: 700;
  margin-bottom: 32px;
}

.conference-card__details {
  display: grid;
  gap: 20px;
  margin-bottom: 36px;
}

.conference-card__details div {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: 16px;
  align-items: baseline;
}

.conference-card__details dt {
  font-size: 0.8125rem;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.6);
}

.conference-card__details dd {
  font-size: 0.9375rem;
}

.conference-card__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.conference-card__actions .btn {
  font-weight: 700;
  min-width: 200px;
  padding: 16px 32px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.25);
}

.conference-card__actions .btn--primary {
  background: var(--white);
  color: var(--navy-700);
  border-color: var(--white);
}

.conference-card__actions .btn--primary:hover {
  background: var(--navy-50);
  border-color: var(--navy-50);
  color: var(--navy-800);
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.3);
}

.conference-card__actions .btn--outline {
  background: rgba(255, 255, 255, 0.15);
  color: var(--white);
  border-color: var(--white);
}

.conference-card__actions .btn--outline:hover {
  background: var(--white);
  border-color: var(--white);
  color: var(--navy-700);
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.3);
}

.past-conferences__title {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--navy-800);
  margin-bottom: 20px;
}

.past-list li {
  display: grid;
  grid-template-columns: 64px 1fr auto;
  align-items: center;
  gap: 16px;
  padding: 16px 0;
  border-bottom: 1px solid var(--border);
}

.past-list li:last-child {
  border-bottom: none;
}

.past-list__year {
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--navy-500);
}

.past-list__name {
  font-size: 0.9375rem;
  color: var(--text);
}

.past-list__link {
  font-size: 0.875rem;
  font-weight: 500;
  white-space: nowrap;
}

/* ========================================
   Contact
   ======================================== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 48px;
  align-items: start;
}

.contact-list div {
  margin-bottom: 24px;
}

.contact-list dt {
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--navy-500);
  margin-bottom: 6px;
}

.contact-list dd {
  font-size: 0.9375rem;
  color: var(--text);
}

.contact-list a {
  color: var(--navy-600);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.x-embed {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
}

.x-embed__header {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 20px 24px;
  background: var(--navy-700);
  color: var(--white);
}

.x-embed__logo {
  flex-shrink: 0;
}

.x-embed__title {
  font-size: 0.8125rem;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.7);
  margin-bottom: 2px;
}

.x-embed__account {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--white);
}

.x-embed__account:hover {
  color: rgba(255, 255, 255, 0.85);
}

.x-embed__timeline {
  min-height: 480px;
  background: var(--white);
}

.x-embed__timeline iframe {
  width: 100% !important;
}

/* ========================================
   Footer
   ======================================== */
.footer {
  background: var(--navy-900);
  color: rgba(255, 255, 255, 0.7);
  padding-block: 64px 32px;
}

.footer__inner {
  display: grid;
  gap: 32px;
}

.footer__logo {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--white);
  margin-bottom: 8px;
}

.footer__tagline {
  font-size: 0.875rem;
}

.footer__nav ul {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
}

.footer__nav a {
  font-size: 0.875rem;
  color: rgba(255, 255, 255, 0.7);
}

.footer__nav a:hover {
  color: var(--white);
}

.footer__copy {
  font-size: 0.8125rem;
  padding-top: 32px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

/* ========================================
   Responsive
   ======================================== */
@media (max-width: 900px) {
  .contact-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .container {
    width: min(1120px, 100% - 32px);
  }

  .header__toggle {
    display: flex;
  }

  .header__nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--navy-700);
    padding: 24px;
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: transform var(--transition), opacity var(--transition), visibility var(--transition);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  }

  .header__nav.is-open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .header__list {
    flex-direction: column;
    gap: 0;
  }

  .header__list a {
    display: block;
    padding: 14px 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  }

  .section {
    padding-block: 64px;
  }

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

  .overview-block {
    padding: 28px 24px;
  }

  .conference-card {
    padding: 32px 24px;
  }

  .conference-card__details div {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .conference-card__actions {
    flex-direction: column;
  }

  .conference-card__actions .btn {
    width: 100%;
  }

  .past-list li {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .officers-table thead {
    display: none;
  }

  .officers-table tbody tr {
    display: block;
    padding: 16px;
    border-bottom: 1px solid var(--border);
  }

  .officers-table tbody tr:last-child {
    border-bottom: none;
  }

  .officers-table td {
    display: grid;
    grid-template-columns: 72px 1fr;
    gap: 8px;
    padding: 6px 0;
    border-bottom: none;
  }

  .officers-table td::before {
    content: attr(data-label);
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--navy-500);
  }
}

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

  .hero__actions .btn {
    width: 100%;
  }
}