:root {
    --night: #061426;
    --night-soft: #0b2138;
    --panel: rgba(9, 31, 52, 0.88);
    --panel-strong: rgba(7, 24, 42, 0.96);
    --cyan: #43f0ed;
    --cyan-soft: #a6fffb;
    --copper: #e8833d;
    --cream: #fff4dd;
    --text: #eaf8f7;
    --muted: #a7c5ca;
    --line: rgba(67, 240, 237, 0.24);
    --shadow: 0 24px 70px rgba(0, 0, 0, 0.36);
}

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

html {
    color-scheme: dark;
    scroll-behavior: smooth;
}

body {
    min-height: 100vh;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans", "Yu Gothic", Meiryo, sans-serif;
    line-height: 1.85;
    color: var(--text);
    background:
        radial-gradient(circle at 16% 2%, rgba(67, 240, 237, 0.16), transparent 30rem),
        radial-gradient(circle at 92% 12%, rgba(232, 131, 61, 0.16), transparent 26rem),
        linear-gradient(180deg, #04101f 0%, var(--night) 44%, #030b15 100%);
}

body::before {
    content: "";
    position: fixed;
    inset: 0;
    pointer-events: none;
    opacity: 0.24;
    background-image:
        linear-gradient(rgba(67, 240, 237, 0.08) 1px, transparent 1px),
        linear-gradient(90deg, rgba(67, 240, 237, 0.08) 1px, transparent 1px);
    background-size: 44px 44px;
    mask-image: linear-gradient(to bottom, transparent, #000 28%, #000 76%, transparent);
}

a {
    color: var(--cyan-soft);
}

a:hover {
    color: #fff;
}

.shell {
    position: relative;
    width: min(1040px, calc(100% - 32px));
    margin: 0 auto;
    padding: 28px 0 72px;
}

.topbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
    margin-bottom: 28px;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    color: var(--text);
    text-decoration: none;
    font-weight: 900;
    letter-spacing: 0.08em;
}

.brand-mark {
    display: grid;
    width: 38px;
    height: 38px;
    place-items: center;
    border: 1px solid var(--line);
    border-radius: 10px;
    color: var(--cyan);
    background: rgba(67, 240, 237, 0.08);
    box-shadow: inset 0 0 18px rgba(67, 240, 237, 0.08);
}

.nav {
    display: flex;
    flex-wrap: wrap;
    justify-content: flex-end;
    gap: 8px;
}

.nav a,
.button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 44px;
    padding: 9px 15px;
    border: 1px solid var(--line);
    border-radius: 10px;
    color: var(--text);
    background: rgba(7, 28, 48, 0.7);
    text-decoration: none;
    font-weight: 750;
    transition: transform 160ms ease, border-color 160ms ease, background 160ms ease;
}

.nav a:hover,
.button:hover {
    transform: translateY(-2px);
    border-color: rgba(67, 240, 237, 0.7);
    background: rgba(16, 52, 78, 0.92);
}

.button-primary {
    color: #04131e;
    border-color: transparent;
    background: linear-gradient(135deg, var(--cyan) 0%, #8afff6 100%);
    box-shadow: 0 12px 36px rgba(67, 240, 237, 0.18);
}

.button-primary:hover {
    color: #04131e;
    background: linear-gradient(135deg, #77fff6 0%, #b4fff9 100%);
}

.hero,
.document,
.card {
    border: 1px solid var(--line);
    background: linear-gradient(145deg, rgba(14, 43, 67, 0.94), var(--panel));
    box-shadow: var(--shadow);
}

.hero {
    position: relative;
    overflow: hidden;
    display: grid;
    grid-template-columns: minmax(0, 1fr) 210px;
    gap: 32px;
    align-items: center;
    padding: clamp(28px, 6vw, 58px);
    border-radius: 24px;
}

.hero::after {
    content: "16";
    position: absolute;
    right: 220px;
    bottom: -70px;
    color: rgba(67, 240, 237, 0.035);
    font: 900 clamp(9rem, 22vw, 17rem)/1 monospace;
    letter-spacing: -0.12em;
    pointer-events: none;
}

.eyebrow {
    margin-bottom: 10px;
    color: var(--copper);
    font-size: 0.82rem;
    font-weight: 900;
    letter-spacing: 0.18em;
    text-transform: uppercase;
}

h1 {
    margin-bottom: 14px;
    color: var(--cream);
    font-size: clamp(2rem, 6vw, 4rem);
    line-height: 1.08;
    letter-spacing: -0.035em;
}

.hero h1 span {
    color: var(--cyan);
}

.lead {
    max-width: 660px;
    color: var(--muted);
    font-size: clamp(1rem, 2.4vw, 1.16rem);
}

.actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 26px;
}

.app-icon {
    position: relative;
    z-index: 1;
    width: 100%;
    height: auto;
    max-width: 210px;
    aspect-ratio: 1;
    justify-self: end;
    border: 1px solid rgba(255, 255, 255, 0.16);
    border-radius: 24%;
    object-fit: cover;
    box-shadow: 0 24px 54px rgba(0, 0, 0, 0.42), 0 0 40px rgba(67, 240, 237, 0.08);
}

.grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px;
    margin-top: 18px;
}

.card {
    padding: 28px;
    border-radius: 18px;
}

.card h2 {
    margin-bottom: 10px;
    color: var(--cream);
    font-size: 1.24rem;
}

.card p,
.card li {
    color: var(--muted);
}

.document {
    padding: clamp(26px, 6vw, 56px);
    border-radius: 24px;
}

.document-header {
    padding-bottom: 28px;
    border-bottom: 1px solid var(--line);
}

.document-header h1 {
    font-size: clamp(2rem, 5vw, 3.2rem);
}

.meta {
    color: var(--muted);
    font-size: 0.92rem;
}

.summary {
    margin: 30px 0 6px;
    padding: 20px 22px;
    border: 1px solid rgba(67, 240, 237, 0.28);
    border-left: 4px solid var(--cyan);
    border-radius: 12px;
    color: var(--cyan-soft);
    background: rgba(67, 240, 237, 0.06);
}

.document section {
    scroll-margin-top: 20px;
}

.document h2 {
    margin: 34px 0 12px;
    color: var(--cream);
    font-size: 1.3rem;
}

.document h3 {
    margin: 22px 0 8px;
    color: var(--cyan-soft);
    font-size: 1.05rem;
}

.document p,
.document li {
    color: #c4dadd;
}

.document ul,
.document ol,
.card ul {
    padding-left: 1.35rem;
}

.document li + li,
.card li + li {
    margin-top: 6px;
}

.callout {
    margin-top: 26px;
    padding: 20px 22px;
    border: 1px solid rgba(232, 131, 61, 0.28);
    border-radius: 14px;
    background: rgba(232, 131, 61, 0.07);
}

.callout strong {
    color: #ffc18f;
}

.faq {
    margin-top: 18px;
}

.faq details {
    border-top: 1px solid var(--line);
    padding: 18px 2px;
}

.faq details:last-child {
    border-bottom: 1px solid var(--line);
}

.faq summary {
    cursor: pointer;
    color: var(--cream);
    font-weight: 800;
}

.faq details p,
.faq details ul {
    margin-top: 10px;
}

.contact-box {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 24px;
    align-items: center;
    margin-top: 30px;
    padding: 24px;
    border: 1px solid rgba(67, 240, 237, 0.28);
    border-radius: 16px;
    background: rgba(67, 240, 237, 0.06);
}

.contact-box h2 {
    margin: 0 0 8px;
}

.footer {
    display: flex;
    justify-content: space-between;
    gap: 18px;
    margin-top: 26px;
    padding: 0 4px;
    color: #789ba2;
    font-size: 0.84rem;
}

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

.footer a {
    color: #9bc4c8;
}

@media (max-width: 720px) {
    .topbar,
    .footer {
        align-items: flex-start;
        flex-direction: column;
    }

    .nav {
        justify-content: flex-start;
    }

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

    .hero::after {
        right: -12px;
        bottom: -26px;
    }

    .app-icon {
        width: 138px;
        justify-self: start;
        order: -1;
    }

    .grid,
    .contact-box {
        grid-template-columns: 1fr;
    }

    .contact-box .button {
        justify-self: start;
    }
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    .nav a,
    .button {
        transition: none;
    }
}