:root {
    --bg-dark: #070d15;
    --bg-mid: #121d2d;
    --bg-soft: #efe8de;
    --surface: rgba(250, 247, 241, 0.92);
    --surface-soft: rgba(226, 236, 247, 0.86);
    --surface-strong: rgba(255, 252, 247, 0.96);
    --ink: #182231;
    --muted: #677482;
    --line: rgba(24, 34, 49, 0.1);
    --accent: #3c6fa0;
    --accent-strong: #16263d;
    --accent-soft: #d29c5b;
    --accent-soft-strong: #8d5d29;
    --glow: #8fc4ff;
    --quantum: #73d4ff;
    --shadow: 0 28px 64px rgba(7, 13, 21, 0.22);
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    color: var(--ink);
    font-family: "IBM Plex Sans JP", sans-serif;
    background:
        radial-gradient(circle at 10% 14%, rgba(143, 196, 255, 0.16), transparent 18%),
        radial-gradient(circle at 86% 12%, rgba(210, 156, 91, 0.18), transparent 16%),
        linear-gradient(180deg, #04070d 0%, #101927 16%, #eee7dc 16.1%, #f7f1e8 100%);
    min-height: 100vh;
}

body::before {
    content: "";
    position: fixed;
    inset: 0;
    pointer-events: none;
    background-image:
        radial-gradient(circle, rgba(255, 255, 255, 0.2) 0 1px, transparent 1.5px),
        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: 108px 108px, 46px 46px, 46px 46px;
    mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.86), rgba(0, 0, 0, 0.08));
}

a {
    color: inherit;
    text-decoration: none;
}

button,
input {
    font: inherit;
}

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

.page-shell {
    width: min(1180px, calc(100% - 32px));
    margin: 0 auto;
    padding-bottom: 80px;
}

.site-header {
    position: sticky;
    top: 14px;
    z-index: 20;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
    margin: 18px 0 20px;
    padding: 16px 22px;
    border-radius: 999px;
    background: rgba(7, 13, 21, 0.78);
    border: 1px solid rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(18px);
    box-shadow: 0 16px 38px rgba(0, 0, 0, 0.24);
}

.brand,
h1,
h2,
h3,
.signal-main,
.formula-block,
.window-label,
.footer-link,
.canvas-caption strong {
    font-family: "Shippori Mincho", serif;
}

.brand {
    color: #f7efe1;
    font-size: 1.14rem;
    letter-spacing: 0.1em;
}

.site-nav {
    display: flex;
    flex-wrap: wrap;
    justify-content: flex-end;
    gap: 18px;
    color: rgba(247, 239, 225, 0.84);
    font-size: 0.95rem;
}

.site-nav a:hover,
.site-nav a:focus-visible,
.footer-link:hover,
.footer-link:focus-visible {
    color: white;
}

.section,
.signal-strip,
.site-footer {
    opacity: 0;
    transform: translateY(26px);
    transition: opacity 520ms ease, transform 520ms ease;
}

.reveal.is-visible,
.site-footer.is-visible {
    opacity: 1;
    transform: translateY(0);
}

.hero {
    display: grid;
    grid-template-columns: minmax(0, 0.96fr) minmax(0, 1.04fr);
    gap: 24px;
    padding: 34px 0 22px;
}

.hero-copy,
.hero-panel,
.concept-card,
.formula-card,
.inside-card,
.model-card,
.comparison-card,
.string-card,
.demo-panel,
.canvas-panel,
.link-card,
.hero-note,
.signal-strip,
.site-footer {
    border: 1px solid rgba(255, 255, 255, 0.58);
    background: var(--surface);
    box-shadow: var(--shadow);
    backdrop-filter: blur(14px);
}

.hero-copy {
    min-width: 0;
    padding: 40px 30px 40px 36px;
    border-radius: 38px;
    position: relative;
    overflow: hidden;
}

.hero-copy::after {
    content: "";
    position: absolute;
    inset: auto -84px -126px auto;
    width: 320px;
    height: 320px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(210, 156, 91, 0.44), rgba(210, 156, 91, 0));
}

.hero-panel {
    min-width: 0;
    padding: 26px;
    border-radius: 36px;
    display: grid;
    gap: 18px;
    background: rgba(240, 246, 252, 0.14);
}

.eyebrow,
.card-label,
.signal-kicker {
    margin: 0 0 12px;
    color: var(--accent-strong);
    font-size: 0.84rem;
    font-weight: 700;
    letter-spacing: 0.2em;
    text-transform: uppercase;
}

h1,
h2,
h3,
.brand {
    line-height: 1.14;
}

h1,
h2 {
    margin: 0;
}

h1 {
    font-size: clamp(2.65rem, 5vw, 4.7rem);
    letter-spacing: -0.04em;
}

.hero-lead,
.section-heading p,
.concept-card p,
.formula-card p,
.inside-card p,
.model-card p,
.comparison-card p,
.string-card p,
.canvas-caption,
.demo-note,
.link-card p,
.hero-note p,
.signal-sub,
.site-footer p {
    color: var(--muted);
}

.hero-lead {
    margin: 20px 0 0;
    font-size: 1.04rem;
    line-height: 1.85;
}

.hero-actions,
.footer-links,
.link-grid,
.mode-row,
.control-grid,
.stat-grid,
.concept-grid,
.inside-grid,
.model-grid,
.comparison-grid,
.string-grid,
.formula-strip,
.demo-grid,
.hero-note-grid {
    display: grid;
    gap: 18px;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    margin-top: 28px;
}

.button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 52px;
    padding: 0 22px;
    border-radius: 999px;
    border: 1px solid transparent;
    transition: transform 180ms ease, box-shadow 180ms ease, background 180ms ease;
    cursor: pointer;
}

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

.button-primary {
    color: white;
    background: linear-gradient(135deg, var(--accent), var(--accent-strong));
    box-shadow: 0 14px 28px rgba(22, 38, 61, 0.28);
}

.button-secondary {
    background: rgba(255, 255, 255, 0.74);
    border-color: var(--line);
}

.hero-points {
    margin: 24px 0 0;
    padding-left: 1.2rem;
    display: grid;
    gap: 10px;
    position: relative;
    z-index: 1;
}

.interior-window,
.control,
.stat-grid article,
.mode-chip,
.link-card,
.comparison-card,
.string-card,
.hero-note {
    background: linear-gradient(145deg, rgba(255, 255, 255, 0.96), rgba(229, 238, 247, 0.86));
    border: 1px solid rgba(24, 34, 49, 0.08);
}

.interior-window {
    position: relative;
    min-height: 360px;
    border-radius: 28px;
    overflow: hidden;
    background:
        radial-gradient(circle at 52% 54%, rgba(64, 107, 165, 0.18), transparent 26%),
        linear-gradient(180deg, #08111d 0%, #162335 44%, #1e3249 68%, #314760 100%);
}

.orbit,
.horizon-shell,
.quantum-ring,
.string-loop {
    position: absolute;
    border-radius: 50%;
}

.orbit {
    border: 1px dashed rgba(143, 196, 255, 0.18);
}

.orbit-a {
    inset: 26px 44px 44px 44px;
}

.orbit-b {
    inset: 58px 82px 82px 82px;
}

.horizon-shell {
    left: 50%;
    top: 50%;
    width: 176px;
    height: 176px;
    transform: translate(-50%, -50%);
    border: 2px solid rgba(143, 196, 255, 0.68);
    box-shadow: 0 0 24px rgba(143, 196, 255, 0.34), inset 0 0 24px rgba(143, 196, 255, 0.18);
}

.quantum-ring {
    left: 50%;
    top: 50%;
    width: 220px;
    height: 220px;
    transform: translate(-50%, -50%);
    border: 10px solid rgba(115, 212, 255, 0.08);
    box-shadow: inset 0 0 42px rgba(115, 212, 255, 0.14);
}

.core-dot {
    position: absolute;
    left: 50%;
    top: 50%;
    width: 34px;
    height: 34px;
    transform: translate(-50%, -50%);
    border-radius: 50%;
    background: radial-gradient(circle, rgba(255, 220, 173, 1) 0%, rgba(210, 156, 91, 0.95) 45%, rgba(210, 156, 91, 0) 76%);
    box-shadow: 0 0 44px rgba(210, 156, 91, 0.4);
}

.infall-stream {
    position: absolute;
    left: 20%;
    right: 20%;
    height: 2px;
    border-radius: 999px;
    background: linear-gradient(90deg, rgba(255, 255, 255, 0), rgba(255, 255, 255, 0.28), rgba(210, 156, 91, 0.56), rgba(255, 255, 255, 0));
    filter: blur(0.4px);
}

.stream-a { top: 34%; transform: rotate(-14deg); }
.stream-b { top: 48%; transform: rotate(0deg); }
.stream-c { top: 62%; transform: rotate(14deg); }

.string-loop {
    border: 2px solid rgba(115, 212, 255, 0.36);
    mix-blend-mode: screen;
}

.loop-a {
    left: 50%;
    top: 50%;
    width: 122px;
    height: 68px;
    transform: translate(-50%, -50%) rotate(18deg);
}

.loop-b {
    left: 50%;
    top: 50%;
    width: 86px;
    height: 126px;
    transform: translate(-50%, -50%) rotate(-24deg);
}

.boundary-bit {
    position: absolute;
    width: 10px;
    height: 10px;
    border-radius: 4px;
    background: rgba(115, 212, 255, 0.85);
    box-shadow: 0 0 12px rgba(115, 212, 255, 0.56);
}

.bit-a { left: 44%; top: 14%; }
.bit-b { left: 58%; top: 18%; }
.bit-c { left: 70%; top: 36%; }
.bit-d { left: 72%; top: 58%; }
.bit-e { left: 56%; top: 74%; }
.bit-f { left: 34%; top: 68%; }

.window-label {
    position: absolute;
    padding: 8px 12px;
    border-radius: 999px;
    background: rgba(7, 13, 21, 0.46);
    color: rgba(247, 239, 225, 0.92);
    font-size: 0.78rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.label-horizon { left: 18px; bottom: 18px; }
.label-interior { right: 18px; top: 18px; }
.label-quantum { right: 18px; bottom: 18px; }

.hero-note-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
}

.hero-note,
.concept-card,
.formula-card,
.inside-card,
.model-card,
.comparison-card,
.string-card,
.demo-panel,
.canvas-panel,
.link-card {
    padding: 24px 26px;
    border-radius: 28px;
}

.strong-card,
.strong-note {
    background: linear-gradient(145deg, rgba(233, 243, 255, 0.98), rgba(205, 225, 246, 0.9));
}

.warm-card,
.warm-note {
    background: linear-gradient(145deg, rgba(255, 240, 224, 0.98), rgba(242, 205, 161, 0.9));
}

.night-card,
.night-note {
    background: linear-gradient(145deg, rgba(15, 24, 36, 0.98), rgba(38, 54, 77, 0.94));
    color: white;
}

.night-card p,
.night-card .card-label,
.night-card h2,
.night-card h3,
.night-note p,
.night-note .card-label,
.night-note h2,
.night-note h3,
.night-card li {
    color: white;
}

.signal-strip {
    margin-top: 10px;
    padding: 24px 30px;
    border-radius: 30px;
    display: grid;
    grid-template-columns: 220px minmax(0, 1.08fr) minmax(0, 0.92fr);
    gap: 18px;
    align-items: center;
}

.signal-kicker {
    margin: 0;
    font-size: 0.86rem;
}

.signal-main {
    font-size: clamp(1.65rem, 3vw, 2.35rem);
    margin: 0;
}

.signal-sub {
    margin: 0;
    line-height: 1.75;
}

.section {
    margin-top: 88px;
}

.section-heading {
    margin-bottom: 26px;
}

.section-heading h2 {
    font-size: clamp(2rem, 3.5vw, 3.1rem);
}

.section-heading p {
    margin: 12px 0 0;
    max-width: 860px;
    line-height: 1.85;
}

.concept-grid,
.inside-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
}

.model-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
}

.comparison-grid,
.string-grid,
.link-grid,
.formula-strip {
    grid-template-columns: repeat(2, minmax(0, 1fr));
}

.formula-block {
    font-size: clamp(1.08rem, 2vw, 1.42rem);
    color: var(--ink);
    line-height: 1.6;
}

.night-card .formula-block,
.night-note .formula-block {
    color: rgba(247, 239, 225, 0.96);
}

.mode-row {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.mode-chip {
    min-height: 44px;
    padding: 0 18px;
    border-radius: 999px;
    border: 1px solid rgba(24, 34, 49, 0.08);
    color: var(--accent-strong);
    transition: transform 180ms ease, box-shadow 180ms ease, background 180ms ease;
    cursor: pointer;
}

.mode-chip.is-active {
    color: white;
    background: linear-gradient(135deg, var(--accent), var(--accent-strong));
    box-shadow: 0 14px 24px rgba(22, 38, 61, 0.22);
}

.demo-grid {
    grid-template-columns: minmax(0, 0.94fr) minmax(340px, 1.06fr);
}

.control-grid {
    margin-top: 20px;
    grid-template-columns: repeat(2, minmax(0, 1fr));
}

.control {
    display: grid;
    gap: 8px;
    padding: 18px 20px;
    border-radius: 22px;
}

.control span {
    color: var(--accent-strong);
    font-weight: 600;
}

.control input {
    width: 100%;
    accent-color: var(--accent);
}

.stat-grid {
    margin-top: 18px;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 14px;
}

.stat-grid article {
    padding: 18px 20px;
    border-radius: 22px;
}

.stat-grid span {
    color: var(--muted);
    font-size: 0.9rem;
}

.stat-grid strong {
    display: block;
    margin-top: 8px;
}

.demo-panel,
.canvas-panel {
    background: linear-gradient(180deg, rgba(252, 254, 255, 0.97), rgba(226, 236, 247, 0.88));
}

.demo-note,
.canvas-caption {
    margin: 18px 0 0;
    line-height: 1.8;
}

.demo-canvas {
    width: 100%;
    border-radius: 28px;
    background: linear-gradient(180deg, rgba(6, 10, 16, 0.98), rgba(18, 27, 39, 0.98));
    border: 1px solid rgba(255, 255, 255, 0.08);
    box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.03);
}

.site-footer {
    margin-top: 64px;
    padding: 24px 30px;
    border-radius: 28px;
    background: rgba(7, 13, 21, 0.86);
    border: 1px solid rgba(255, 255, 255, 0.08);
    color: rgba(247, 239, 225, 0.82);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
}

.site-footer p {
    margin: 0;
}

.footer-links {
    display: flex;
    gap: 18px;
    flex-wrap: wrap;
}

.footer-link {
    color: white;
    font-weight: 600;
}

@media (max-width: 1180px) {
    .concept-grid,
    .inside-grid,
    .model-grid,
    .stat-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 1040px) {
    .hero,
    .signal-strip,
    .demo-grid,
    .formula-strip,
    .comparison-grid,
    .string-grid,
    .link-grid {
        grid-template-columns: 1fr;
    }

    .hero-note-grid,
    .control-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 760px) {
    .page-shell {
        width: min(100% - 20px, 1200px);
    }

    .site-header {
        position: static;
        flex-direction: column;
        align-items: flex-start;
        border-radius: 28px;
    }

    .site-nav {
        justify-content: flex-start;
        gap: 12px 14px;
    }

    .hero-copy,
    .hero-panel,
    .hero-note,
    .concept-card,
    .formula-card,
    .inside-card,
    .model-card,
    .comparison-card,
    .string-card,
    .demo-panel,
    .canvas-panel,
    .link-card,
    .signal-strip,
    .site-footer {
        padding: 22px;
        border-radius: 24px;
    }

    .hero-actions {
        flex-direction: column;
    }

    .button,
    .mode-chip {
        width: 100%;
    }

    .hero-note-grid,
    .concept-grid,
    .inside-grid,
    .model-grid,
    .comparison-grid,
    .string-grid,
    .control-grid,
    .stat-grid,
    .link-grid {
        grid-template-columns: 1fr;
    }

    .hero,
    .section {
        margin-top: 68px;
    }

    .interior-window {
        min-height: 320px;
    }

    .site-footer {
        flex-direction: column;
        align-items: flex-start;
    }
}