.rulebook-open-btn {
    position: absolute;
    left: clamp(18px, 4vw, 48px);
    top: 50%;
    transform: translateY(-50%);
    z-index: 4;
    padding: 12px 18px;
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 8px;
    background: rgba(17, 24, 39, 0.78);
    color: #fff;
    box-shadow: 0 10px 26px rgba(0, 0, 0, 0.25);
    cursor: pointer;
    font-size: 1rem;
    font-weight: 700;
}

.rulebook-open-btn:hover {
    background: rgba(17, 24, 39, 0.94);
    transform: translateY(calc(-50% - 2px));
}

.rulebook-overlay {
    position: fixed;
    inset: 0;
    z-index: 30;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: clamp(16px, 3vw, 36px);
    background: rgba(10, 14, 28, 0.62);
}

.rulebook-overlay.hidden {
    display: none;
}

.rulebook-modal {
    width: min(980px, 96vw);
    height: min(720px, 92vh);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    border: 1px solid rgba(255, 255, 255, 0.28);
    border-radius: 8px;
    background: rgba(248, 250, 252, 0.98);
    box-shadow: 0 24px 70px rgba(0, 0, 0, 0.36);
    color: #111827;
}

.rulebook-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 18px 22px;
    border-bottom: 1px solid #d7dce5;
    background: #111827;
    color: #fff;
}

.rulebook-eyebrow {
    margin: 0 0 3px 0;
    color: #a8b3c7;
    font-size: 0.78rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.rulebook-header h2 {
    margin: 0;
    font-size: 1.45rem;
}

.rulebook-close-btn {
    width: 40px;
    height: 40px;
    border: 1px solid rgba(255, 255, 255, 0.32);
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.1);
    color: #fff;
    cursor: pointer;
    font-size: 1.6rem;
    line-height: 1;
}

.rulebook-close-btn:hover {
    background: rgba(255, 255, 255, 0.18);
}

.rulebook-layout {
    display: grid;
    grid-template-columns: 210px minmax(0, 1fr);
    min-height: 0;
    flex: 1;
}

.rulebook-tabs {
    display: flex;
    flex-direction: column;
    gap: 6px;
    padding: 16px;
    overflow-y: auto;
    border-right: 1px solid #d7dce5;
    background: #eef2f7;
}

.rulebook-tab {
    width: 100%;
    padding: 11px 12px;
    border: 1px solid transparent;
    border-radius: 8px;
    background: transparent;
    color: #374151;
    cursor: pointer;
    font-weight: 700;
    text-align: left;
}

.rulebook-tab:hover {
    background: #e0e7f0;
}

.rulebook-tab.active {
    border-color: #2563eb;
    background: #fff;
    color: #111827;
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.12);
}

.rulebook-content {
    min-width: 0;
    overflow-y: auto;
    padding: 24px 28px 34px;
}

.rulebook-content h3 {
    margin: 0 0 10px;
    color: #111827;
    font-size: 1.55rem;
}

.rulebook-lead {
    margin: 0 0 18px;
    color: #334155;
    font-size: 1.02rem;
    line-height: 1.7;
}

.rulebook-block {
    margin-top: 16px;
}

.rulebook-block h4 {
    margin: 0 0 8px;
    color: #1f2937;
    font-size: 1rem;
}

.rulebook-block ul,
.rulebook-block ol {
    margin: 0;
    padding-left: 1.25rem;
    color: #243244;
    line-height: 1.8;
}

.rulebook-block li + li {
    margin-top: 5px;
}

.rulebook-block-note {
    padding: 12px 14px;
    border-left: 4px solid #2563eb;
    border-radius: 6px;
    background: #eff6ff;
}

.rulebook-block-note p {
    margin: 0;
    color: #1e3a8a;
    line-height: 1.7;
}

.rulebook-block-example {
    padding: 12px 14px;
    border-radius: 6px;
    background: #f8fafc;
    border: 1px solid #dbe3ee;
}

.rulebook-block-terms dl {
    display: grid;
    grid-template-columns: 120px minmax(0, 1fr);
    gap: 8px 14px;
    margin: 0;
}

.rulebook-block-terms dt {
    color: #111827;
    font-weight: 800;
}

.rulebook-block-terms dd {
    margin: 0;
    color: #374151;
    line-height: 1.6;
}

@media (max-width: 780px) {
    .rulebook-open-btn {
        top: auto;
        bottom: 20px;
        left: 20px;
        transform: none;
    }

    .rulebook-open-btn:hover {
        transform: translateY(-2px);
    }

    .rulebook-modal {
        height: 94vh;
    }

    .rulebook-layout {
        grid-template-columns: 1fr;
    }

    .rulebook-tabs {
        flex-direction: row;
        overflow-x: auto;
        border-right: none;
        border-bottom: 1px solid #d7dce5;
    }

    .rulebook-tab {
        flex: 0 0 auto;
        width: auto;
        white-space: nowrap;
    }

    .rulebook-content {
        padding: 20px;
    }

    .rulebook-block-terms dl {
        grid-template-columns: 1fr;
    }
}