:root {
  --base: #44e141;
  --ink: #111513;
  --muted: #5a625d;
  --paper: #f3f5f2;
  --mist: #e7ece6;
  --sage: #44e141;
  --deep: #050805;
  --gold: #44e141;
  --coral: #ff6b5b;
  --line: rgba(17, 21, 19, 0.13);
  --shadow: 0 18px 45px rgba(17, 21, 19, 0.1);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "Noto Sans JP", system-ui, sans-serif;
  line-height: 1.8;
}

a {
  color: inherit;
}

.site-header {
  position: fixed;
  z-index: 20;
  top: 0;
  left: 0;
  right: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 18px clamp(18px, 4vw, 56px);
  color: #fff;
  background: rgba(5, 8, 5, 0.9);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.16);
  backdrop-filter: blur(16px);
  transition: background 0.25s ease, box-shadow 0.25s ease, color 0.25s ease;
}

.site-header.is-scrolled {
  color: #fff;
  background: rgba(5, 8, 5, 0.94);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.18);
  backdrop-filter: blur(16px);
}

.brand {
  display: inline-flex;
  align-items: center;
  text-decoration: none;
}

.brand img {
  display: block;
  width: clamp(220px, 31vw, 430px);
  height: auto;
}

.nav {
  display: flex;
  gap: clamp(12px, 3vw, 28px);
  font-size: 14px;
  font-weight: 700;
}

.nav a {
  text-decoration: none;
}

.hero {
  position: relative;
  min-height: 92svh;
  display: grid;
  align-items: end;
  overflow: hidden;
  color: #fff;
}

.hero-media,
.hero-overlay {
  position: absolute;
  inset: 0;
}

.hero-media {
  background: #14351f;
}

.slide {
  position: absolute;
  inset: 0;
  opacity: 0;
  transform: scale(1.04);
  animation: fadeSlide 24s infinite;
  background-size: cover;
  background-position: center;
}

.slide-a {
  opacity: 1;
  background-image:
    linear-gradient(120deg, rgba(68, 225, 65, 0.22), rgba(20, 53, 31, 0.18)),
    url("assets/soukai-2025-0126.jpg");
}

.slide-b {
  animation-delay: 6s;
  background-image:
    linear-gradient(120deg, rgba(31, 143, 69, 0.3), rgba(16, 32, 20, 0.18)),
    url("assets/soukai-2025-0381.jpg");
}

.slide-c {
  animation-delay: 12s;
  background-image:
    linear-gradient(120deg, rgba(68, 225, 65, 0.2), rgba(20, 53, 31, 0.22)),
    url("assets/soukai-2025-0448.jpg");
}

.slide-d {
  animation-delay: 18s;
  background-image:
    linear-gradient(120deg, rgba(31, 143, 69, 0.24), rgba(16, 32, 20, 0.2)),
    url("assets/soukai-2025-1359.jpg");
}

.hero-overlay {
  background:
    linear-gradient(90deg, rgba(5, 8, 5, 0.72), rgba(12, 19, 13, 0.42) 52%, rgba(68, 225, 65, 0.12)),
    linear-gradient(0deg, rgba(5, 8, 5, 0.5), transparent 42%);
}

.hero-inner {
  position: relative;
  z-index: 2;
  width: min(1120px, calc(100% - 36px));
  margin: 0 auto;
  padding: 140px 0 88px;
}

.eyebrow,
.section-kicker,
.label {
  font-size: 13px;
  font-weight: 900;
  text-transform: uppercase;
}

.eyebrow {
  color: #cfff9a;
}

.hero-date {
  max-width: 920px;
  margin-bottom: 18px;
  font-size: clamp(20px, 3.2vw, 36px);
  line-height: 1.35;
  letter-spacing: 0;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 820px;
  margin-bottom: 22px;
  font-family: "Noto Sans JP", system-ui, sans-serif;
  font-weight: 900;
  font-size: clamp(42px, 7vw, 86px);
  line-height: 1.08;
}

.hero-title-accent {
  display: inline-block;
  margin: 0 0.08em;
  color: var(--base);
  text-shadow: 0 0 28px rgba(68, 225, 65, 0.35);
}

h2 {
  margin-bottom: 20px;
  font-size: clamp(28px, 4vw, 46px);
  line-height: 1.3;
}

h3 {
  margin-bottom: 12px;
  font-size: 21px;
  line-height: 1.45;
}

.lead {
  max-width: 720px;
  font-size: clamp(17px, 2.3vw, 22px);
  font-weight: 500;
}

.hero-callout {
  display: inline-block;
  max-width: 900px;
  margin-bottom: 28px;
  padding: 10px 18px;
  border-left: 6px solid var(--base);
  color: #fff;
  background: rgba(5, 8, 5, 0.5);
  font-size: clamp(24px, 4vw, 42px);
  font-weight: 900;
  line-height: 1.35;
}

.hero-actions,
.entry {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 12px 22px;
  border: 1px solid transparent;
  border-radius: 999px;
  font-weight: 800;
  text-decoration: none;
  line-height: 1.4;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button.primary {
  color: #051008;
  background: var(--base);
  box-shadow: 0 14px 28px rgba(68, 225, 65, 0.28);
}

.button.secondary {
  color: #fff;
  border-color: rgba(255, 255, 255, 0.62);
  background: rgba(255, 255, 255, 0.08);
}

.button.secondary.dark {
  color: var(--ink);
  border-color: rgba(68, 225, 65, 0.52);
  background: rgba(68, 225, 65, 0.16);
}

.button.large {
  min-width: 240px;
  min-height: 58px;
  font-size: 17px;
}

.section {
  padding: clamp(72px, 10vw, 116px) 0;
}

.section-inner {
  width: min(1120px, calc(100% - 36px));
  margin: 0 auto;
}

.details-band {
  background: #050805;
  color: #fff;
}

.details-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
}

.detail-item {
  min-height: 150px;
  padding: 30px;
  border-left: 1px solid rgba(255, 255, 255, 0.17);
}

.detail-item:last-child {
  border-right: 1px solid rgba(255, 255, 255, 0.17);
}

.detail-item strong,
.detail-item span {
  display: block;
}

.detail-item strong {
  margin: 7px 0 4px;
  font-size: clamp(20px, 2.5vw, 28px);
  line-height: 1.35;
}

.label {
  color: #cfff9a;
}

.split {
  display: grid;
  grid-template-columns: minmax(0, 0.92fr) minmax(320px, 1.08fr);
  gap: clamp(34px, 7vw, 78px);
  align-items: center;
}

.section-kicker {
  margin-bottom: 10px;
  color: var(--gold);
}

.split p,
.caution p,
.entry p,
.audience p,
.sponsor-box p,
.archive p {
  color: var(--muted);
  font-size: 17px;
}

.intro-section {
  position: relative;
  overflow: hidden;
  color: #fff;
  background:
    linear-gradient(90deg, rgba(5, 8, 5, 0.66), rgba(12, 19, 13, 0.46) 48%, rgba(12, 19, 13, 0.18)),
    linear-gradient(0deg, rgba(5, 8, 5, 0.28), rgba(5, 8, 5, 0.04)),
    url("assets/soukai-2025-1251.jpg");
  background-size: cover;
  background-position: center;
}

.intro-section .section-kicker {
  color: #cfff9a;
}

.intro-section .split p {
  color: rgba(255, 255, 255, 0.88);
}

.purpose-grid {
  display: grid;
  gap: 16px;
}

.purpose-card {
  padding: 24px;
  border: 1px solid rgba(68, 225, 65, 0.3);
  border-radius: 8px;
  background: rgba(5, 8, 5, 0.72);
  box-shadow: 0 18px 45px rgba(0, 0, 0, 0.32);
  backdrop-filter: blur(12px);
}

.purpose-card span {
  display: inline-grid;
  place-items: center;
  width: 38px;
  height: 38px;
  margin-bottom: 14px;
  border-radius: 50%;
  color: #051008;
  background: var(--base);
  font-weight: 900;
}

.purpose-card h3 {
  margin-bottom: 8px;
  color: #fff;
}

.purpose-card p {
  margin-bottom: 0;
  color: rgba(255, 255, 255, 0.78);
}

.intro-section .purpose-card p {
  color: rgba(255, 255, 255, 0.78);
}

.flow {
  display: grid;
  gap: 14px;
}

.flow-step {
  display: grid;
  grid-template-columns: 54px 120px 1fr;
  gap: 16px;
  align-items: center;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  box-shadow: var(--shadow);
}

.flow-step span {
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  color: #051008;
  background: var(--base);
  font-weight: 900;
}

.flow-step strong {
  font-size: 18px;
}

.flow-step p {
  margin: 0;
  color: var(--muted);
}

.speaker-photos {
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-auto-rows: 136px;
  gap: 12px;
  align-self: center;
  max-width: 560px;
}

.speaker-photo {
  margin: 0;
  overflow: hidden;
  border-radius: 8px;
  background: var(--mist);
  box-shadow: var(--shadow);
}

.speaker-photo-large {
  grid-row: span 2;
}

.speaker-photo img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.speaker-entry-button {
  margin-top: 8px;
}

.audience-band {
  background: var(--mist);
}

.photo-section {
  background: var(--paper);
}

.section-heading p {
  max-width: 720px;
  color: var(--muted);
  font-size: 17px;
}

.photo-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  grid-auto-rows: minmax(170px, 230px);
  gap: 18px;
}

.photo-card {
  margin: 0;
  border-radius: 8px;
  overflow: hidden;
  background: var(--mist);
  box-shadow: var(--shadow);
}

.photo-card img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.photo-wide {
  grid-row: span 2;
  grid-column: span 2;
}

.photo-tall {
  grid-row: span 2;
}

.audience {
  display: grid;
  grid-template-columns: 0.8fr 1fr;
  gap: 36px 64px;
  align-items: start;
}

.check-list {
  display: grid;
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.check-list li {
  position: relative;
  padding: 18px 20px 18px 54px;
  border-radius: 8px;
  color: var(--ink);
  background: #fff;
  font-weight: 800;
  box-shadow: 0 10px 25px rgba(31, 143, 69, 0.09);
}

.check-list li::before {
  content: "";
  position: absolute;
  left: 20px;
  top: 24px;
  width: 18px;
  height: 10px;
  border-left: 3px solid var(--base);
  border-bottom: 3px solid var(--base);
  transform: rotate(-45deg);
}

.note {
  grid-column: 2;
  margin: -16px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.section-heading {
  max-width: 760px;
  margin-bottom: 32px;
}

.caution-band {
  background: #050805;
  color: #fff;
}

.caution {
  max-width: 900px;
}

.caution p {
  color: rgba(255, 255, 255, 0.78);
}

.entry {
  justify-content: space-between;
  gap: 36px;
}

.entry > div {
  max-width: 720px;
}

.sponsor-section {
  background: var(--mist);
}

.sponsor-layout {
  display: grid;
  grid-template-columns: minmax(0, 0.82fr) minmax(420px, 1.18fr);
  gap: clamp(34px, 6vw, 72px);
  align-items: center;
}

.sponsor-copy > p {
  color: var(--muted);
  font-size: 17px;
}

.sponsor-box {
  margin-top: 28px;
  padding: clamp(22px, 4vw, 34px);
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  box-shadow: var(--shadow);
}

.sponsor-list {
  display: grid;
  gap: 8px;
  margin: 0 0 22px;
  padding-left: 1.2em;
  color: var(--muted);
  font-size: 17px;
}

.sponsor-list li::marker {
  color: var(--base);
}

.sponsor-box p {
  margin-bottom: 8px;
}

.mail-link {
  display: inline-block;
  margin-top: 4px;
  color: var(--ink);
  font-size: clamp(18px, 2vw, 23px);
  font-weight: 900;
  text-decoration-color: var(--base);
  text-decoration-thickness: 3px;
  text-underline-offset: 5px;
}

.archive-section {
  background: #fff;
}

.archive {
  max-width: 900px;
}

.sponsor-gallery {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  grid-auto-rows: 150px;
  gap: 14px;
}

.sponsor-photo {
  margin: 0;
  overflow: hidden;
  border-radius: 8px;
  background: var(--paper);
  box-shadow: var(--shadow);
}

.sponsor-photo-wide {
  grid-row: span 2;
}

.sponsor-photo img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.footer {
  display: flex;
  justify-content: center;
  gap: 20px;
  padding: 34px clamp(18px, 4vw, 56px);
  color: rgba(255, 255, 255, 0.72);
  background: var(--ink);
  font-size: 14px;
  text-align: center;
}

.footer p {
  margin: 0;
}

.footer a {
  text-decoration: none;
}

@keyframes fadeSlide {
  0% {
    opacity: 0;
    transform: scale(1.04);
  }

  8%,
  33% {
    opacity: 1;
  }

  45%,
  100% {
    opacity: 0;
    transform: scale(1.1);
  }
}

@media (max-width: 840px) {
  .site-header {
    align-items: flex-start;
    padding: 14px 18px;
  }

  .brand img {
    width: min(58vw, 300px);
  }

  .nav {
    display: none;
  }

  .hero {
    min-height: 88svh;
  }

  .hero-inner {
    padding-bottom: 58px;
  }

  .details-grid,
  .split,
  .sponsor-layout,
  .audience,
  .photo-grid {
    grid-template-columns: 1fr;
  }

  .photo-grid {
    grid-template-rows: none;
  }

  .photo-card {
    aspect-ratio: 4 / 3;
  }

  .photo-wide {
    grid-row: auto;
    grid-column: auto;
  }

  .photo-tall {
    grid-row: auto;
  }

  .detail-item {
    min-height: auto;
    border-left: 0;
    border-top: 1px solid rgba(255, 255, 255, 0.17);
    padding: 24px 0;
  }

  .detail-item:last-child {
    border-right: 0;
  }

  .flow-step {
    grid-template-columns: 46px 1fr;
    gap: 12px;
  }

  .flow-step p {
    grid-column: 2;
  }

  .speaker-photos {
    grid-template-columns: 1fr;
    grid-auto-rows: auto;
    max-width: none;
  }

  .speaker-photo,
  .speaker-photo-large {
    grid-row: auto;
    aspect-ratio: 16 / 9;
  }

  .sponsor-gallery {
    grid-template-columns: 1fr;
    grid-auto-rows: auto;
  }

  .sponsor-photo,
  .sponsor-photo-wide {
    grid-row: auto;
    aspect-ratio: 16 / 9;
  }

  .note {
    grid-column: auto;
    margin-top: -12px;
  }

  .entry {
    align-items: flex-start;
  }
}

@media (max-width: 520px) {
  .hero-actions,
  .button,
  .entry .button {
    width: 100%;
  }

  .hero-overlay {
    background:
      linear-gradient(90deg, rgba(5, 8, 5, 0.76), rgba(12, 19, 13, 0.5)),
      linear-gradient(0deg, rgba(5, 8, 5, 0.58), transparent 46%);
  }
}