:root {
  --ink: #151515;
  --ink-soft: #5c5449;
  --sumi: #0e1111;
  --indigo: #172c46;
  --paper: #f5e8cf;
  --paper-hot: #fff8ea;
  --vermillion: #b7422a;
  --gold: #b68b3c;
  --line: rgba(21, 21, 21, 0.18);
  --shadow: 0 28px 70px rgba(0, 0, 0, 0.28);
  --font-display: "Noto Serif JP", "Yu Mincho", serif;
  --font-body: "Manrope", Arial, sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background:
    radial-gradient(circle at 10% 0%, rgba(183, 66, 42, 0.18), transparent 28rem),
    linear-gradient(135deg, var(--sumi), #17201e 55%, #090b0b);
  color: var(--paper-hot);
  font-family: var(--font-body);
  line-height: 1.6;
  text-rendering: optimizeLegibility;
}

::selection {
  background: var(--vermillion);
  color: var(--paper-hot);
}

a {
  color: inherit;
  text-underline-offset: 0.22em;
}

.skip-link {
  position: fixed;
  left: 1rem;
  top: 1rem;
  transform: translateY(-200%);
  background: var(--paper-hot);
  color: var(--ink);
  padding: 0.7rem 1rem;
  z-index: 20;
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  padding: 1rem clamp(1rem, 4vw, 4rem);
  background: rgba(14, 17, 17, 0.84);
  border-bottom: 1px solid rgba(245, 232, 207, 0.16);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.85rem;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 2.8rem;
  height: 2.8rem;
  border: 2px solid var(--vermillion);
  border-radius: 50%;
  font-family: var(--font-display);
  font-size: 1.45rem;
  color: var(--paper-hot);
}

.brand strong,
.brand small {
  display: block;
}

.brand strong {
  font-size: 0.96rem;
  line-height: 1.15;
}

.brand small {
  color: rgba(255, 248, 234, 0.68);
  font-size: 0.75rem;
  margin-top: 0.1rem;
}

nav {
  display: flex;
  align-items: center;
  gap: clamp(0.8rem, 2vw, 1.6rem);
  font-size: 0.86rem;
  font-weight: 800;
}

nav a {
  text-decoration: none;
  color: rgba(255, 248, 234, 0.74);
}

nav a:hover,
nav a:focus-visible {
  color: var(--paper-hot);
}

.hero {
  min-height: calc(100vh - 80px);
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(22rem, 0.72fr);
  align-items: center;
  gap: clamp(2rem, 6vw, 7rem);
  padding: clamp(4rem, 8vw, 8rem) clamp(1.2rem, 5vw, 5rem);
  overflow: hidden;
  position: relative;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 8% -20% auto auto;
  width: 42rem;
  height: 42rem;
  background: radial-gradient(circle, rgba(183, 66, 42, 0.16), transparent 70%);
  pointer-events: none;
}

h1,
h2,
h3 {
  font-family: var(--font-display);
  line-height: 0.98;
  letter-spacing: 0;
  margin: 0;
}

h1 {
  max-width: 12ch;
  font-size: clamp(4rem, 10vw, 9.8rem);
  font-weight: 900;
}

h2 {
  max-width: 13ch;
  font-size: clamp(2.6rem, 6vw, 6rem);
  font-weight: 900;
}

h3 {
  font-size: clamp(1.35rem, 2.2vw, 2rem);
}

p {
  margin: 0;
}

.hero-copy p {
  max-width: 62ch;
  margin-top: 2rem;
  color: rgba(255, 248, 234, 0.78);
  font-size: clamp(1.05rem, 1.5vw, 1.3rem);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem;
  margin-top: 2.3rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 3rem;
  padding: 0.85rem 1.25rem;
  border-radius: 0.18rem;
  border: 1px solid rgba(255, 248, 234, 0.26);
  font-weight: 900;
  text-decoration: none;
  transition: transform 180ms ease, background 180ms ease, border-color 180ms ease;
}

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

.button.primary {
  background: var(--vermillion);
  border-color: var(--vermillion);
  color: var(--paper-hot);
}

.button.ghost {
  color: var(--paper-hot);
}

.hero-visual {
  position: relative;
  min-height: 34rem;
  display: grid;
  place-items: center;
}

.hero-visual img {
  width: min(100%, 38rem);
  position: relative;
  z-index: 2;
  filter: drop-shadow(0 32px 45px rgba(0, 0, 0, 0.34));
}

.tatami-lines {
  position: absolute;
  inset: 8% -18% 2% 8%;
  background:
    linear-gradient(90deg, transparent 0 23%, rgba(245, 232, 207, 0.08) 23% 23.5%, transparent 23.5% 50%, rgba(245, 232, 207, 0.08) 50% 50.5%, transparent 50.5% 76%, rgba(245, 232, 207, 0.08) 76% 76.5%, transparent 76.5%),
    linear-gradient(0deg, transparent 0 30%, rgba(245, 232, 207, 0.08) 30% 30.5%, transparent 30.5% 68%, rgba(245, 232, 207, 0.08) 68% 68.5%, transparent 68.5%);
  transform: rotate(-7deg);
  border: 1px solid rgba(245, 232, 207, 0.14);
}

.notice {
  padding: 1.2rem clamp(1.2rem, 5vw, 5rem);
  background: var(--vermillion);
  color: var(--paper-hot);
  font-weight: 800;
}

.notice p {
  max-width: 92rem;
}

section {
  padding: clamp(4rem, 8vw, 8rem) clamp(1.2rem, 5vw, 5rem);
}

.section-dark {
  background: var(--indigo);
  color: var(--paper-hot);
}

.section-paper {
  background:
    radial-gradient(circle at 18% 28%, rgba(183, 66, 42, 0.1), transparent 18rem),
    radial-gradient(circle at 86% 18%, rgba(182, 139, 60, 0.13), transparent 20rem),
    linear-gradient(115deg, rgba(21, 21, 21, 0.03), transparent 36%, rgba(21, 21, 21, 0.035)),
    var(--paper);
  color: var(--ink);
}

.section-intro {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(20rem, 0.75fr);
  align-items: end;
  gap: clamp(2rem, 5vw, 6rem);
  margin-bottom: clamp(2.4rem, 5vw, 5rem);
}

.section-intro p,
.practice-grid p,
.sources p,
.contact p {
  color: inherit;
  opacity: 0.78;
  max-width: 68ch;
}

.lineage-rail {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid rgba(245, 232, 207, 0.22);
  border-bottom: 1px solid rgba(245, 232, 207, 0.22);
}

.lineage-rail article {
  padding: clamp(1.4rem, 4vw, 3rem);
  min-height: 20rem;
  border-right: 1px solid rgba(245, 232, 207, 0.22);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.lineage-rail article:last-child {
  border-right: 0;
}

.lineage-rail span {
  color: #e0b15b;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-size: 0.78rem;
}

.lineage-rail p {
  color: rgba(255, 248, 234, 0.72);
}

.practice {
  background: var(--sumi);
}

.practice-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.85fr) minmax(20rem, 1fr);
  gap: clamp(2.4rem, 7vw, 8rem);
  align-items: start;
}

.practice-grid p {
  margin-top: 2rem;
}

.principles {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  border-top: 1px solid rgba(245, 232, 207, 0.18);
}

.principles li {
  display: grid;
  grid-template-columns: minmax(6rem, 0.28fr) 1fr;
  gap: 1.2rem;
  padding: 1.4rem 0;
  border-bottom: 1px solid rgba(245, 232, 207, 0.18);
}

.principles strong {
  color: var(--gold);
  font-family: var(--font-display);
  font-size: 1.4rem;
}

.principles span {
  color: rgba(255, 248, 234, 0.74);
}

.program-list {
  display: grid;
  gap: 1px;
  background: rgba(21, 21, 21, 0.2);
  border: 1px solid rgba(21, 21, 21, 0.2);
}

.program-list article {
  background: rgba(255, 248, 234, 0.78);
  padding: clamp(1.4rem, 4vw, 3rem);
  display: grid;
  grid-template-columns: minmax(12rem, 0.5fr) 1fr;
  gap: 2rem;
  align-items: start;
}

.program-list p {
  color: var(--ink-soft);
}

.sources {
  display: grid;
  grid-template-columns: minmax(0, 0.85fr) minmax(20rem, 0.7fr);
  gap: clamp(2rem, 6vw, 7rem);
  background: #fbf1dc;
  color: var(--ink);
}

.sources ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 0.65rem;
}

.sources a {
  color: var(--vermillion);
  font-weight: 900;
}

.contact {
  background:
    radial-gradient(circle at 80% 10%, rgba(183, 66, 42, 0.2), transparent 30rem),
    var(--sumi);
}

.contact-panel {
  max-width: 62rem;
}

.contact-panel p {
  margin-top: 1.4rem;
  margin-bottom: 2rem;
}

footer {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.4rem clamp(1.2rem, 5vw, 5rem);
  color: rgba(255, 248, 234, 0.58);
  border-top: 1px solid rgba(245, 232, 207, 0.14);
}

footer p {
  font-size: 0.88rem;
}

:focus-visible {
  outline: 3px solid var(--gold);
  outline-offset: 4px;
}

@media (max-width: 920px) {
  .site-header {
    position: static;
    align-items: flex-start;
    flex-direction: column;
  }

  nav {
    width: 100%;
    overflow-x: auto;
    padding-bottom: 0.2rem;
  }

  .hero,
  .section-intro,
  .practice-grid,
  .sources {
    grid-template-columns: 1fr;
  }

  .hero {
    padding-top: 3.2rem;
  }

  .hero-visual {
    min-height: 24rem;
    order: -1;
  }

  .hero-visual img {
    width: min(75vw, 24rem);
  }

  h1 {
    font-size: clamp(3.3rem, 17vw, 6rem);
  }

  .lineage-rail {
    grid-template-columns: 1fr;
  }

  .lineage-rail article {
    border-right: 0;
    border-bottom: 1px solid rgba(245, 232, 207, 0.22);
    min-height: auto;
    gap: 2rem;
  }

  .program-list article,
  .principles li {
    grid-template-columns: 1fr;
  }

  footer {
    flex-direction: column;
  }
}

@media (max-width: 520px) {
  .brand strong {
    max-width: 18rem;
  }

  .hero-actions,
  .button {
    width: 100%;
  }

  h2 {
    font-size: clamp(2.35rem, 15vw, 4rem);
  }
}