:root {
    --paper: #f5f0e6;
    --paper-shade: #ece5d3;
    --sumi: #1a1a1a;
    --sumi-soft: rgba(26, 26, 26, 0.55);
    --vermillion: #c1272d;
}

html, body {
    background:
        radial-gradient(circle at 20% 20%, rgba(180, 160, 120, 0.08), transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(180, 160, 120, 0.06), transparent 50%),
        var(--paper);
    color: var(--sumi);
    background-attachment: fixed;
}

body::before {
    content: '';
    position: fixed;
    inset: 0;
    pointer-events: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='200' height='200'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.8' numOctaves='2' /%3E%3CfeColorMatrix values='0 0 0 0 0.2  0 0 0 0 0.15  0 0 0 0 0.05  0 0 0 0.04 0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
    opacity: 0.8;
    z-index: 0;
}

body > * {
    position: relative;
    z-index: 1;
}

.site-header h1 {
    font-family: "Shippori Mincho", serif;
    font-weight: 500;
    color: var(--sumi);
}

.site-header .subtitle {
    font-family: "Shippori Mincho", serif;
    color: var(--sumi-soft);
    font-size: 0.7rem;
    margin-top: 0.3rem;
    letter-spacing: 0.2em;
}

.seal {
    position: absolute;
    right: 1.2rem;
    top: 0.6rem;
    width: 2.2rem;
    height: 2.2rem;
    border: 2px solid var(--vermillion);
    color: var(--vermillion);
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: "Shippori Mincho", serif;
    font-size: 0.95rem;
    font-weight: 600;
    transform: rotate(-5deg);
    background: rgba(245, 240, 230, 0.6);
}

.book .page {
    background: #fff;
    box-shadow: 0 4px 24px rgba(60, 40, 10, 0.25);
}

.ctrl-btn {
    color: var(--sumi);
    border: 1px solid rgba(26, 26, 26, 0.35);
    font-family: "Shippori Mincho", serif;
    letter-spacing: 0.08em;
    background: rgba(255, 255, 255, 0.3);
}

.ctrl-btn:hover {
    background: var(--sumi);
    color: var(--paper);
    border-color: var(--sumi);
}

.page-indicator {
    color: var(--sumi);
    font-family: "Shippori Mincho", serif;
    letter-spacing: 0.1em;
}

.site-footer {
    color: var(--sumi-soft);
    font-family: "Shippori Mincho", serif;
}

.back-link {
    color: var(--sumi);
    border-color: rgba(26, 26, 26, 0.35);
    background: rgba(255, 255, 255, 0.6);
    font-family: "Shippori Mincho", serif;
}

@media (max-width: 767px) {
    .seal { right: 0.6rem; top: 0.3rem; width: 1.8rem; height: 1.8rem; font-size: 0.75rem; }
}