:root {
    --bg: #0e1426;
    --bg-soft: #151f3a;
    --text: #1a1f2d;
    --muted: #55607a;
    --line: #d8deee;
    --card: #ffffff;
    --brand: #1f3bb3;
    --brand-soft: #e9eeff;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    color: var(--text);
    background: #f6f8fd;
    font-family: "Segoe UI", Tahoma, Arial, sans-serif;
    line-height: 1.55;
}

a {
    color: var(--brand);
}

a:focus-visible,
button:focus-visible,
summary:focus-visible {
    outline: 3px solid #ffb800;
    outline-offset: 2px;
}

.skip-link {
    position: absolute;
    top: -100px;
    left: 12px;
    background: #fff;
    padding: 8px 12px;
    z-index: 1000;
}

.skip-link:focus {
    top: 8px;
}

.container {
    width: min(1120px, 92%);
    margin: 0 auto;
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 20;
    background: #fff;
    border-bottom: 1px solid var(--line);
}

.nav-wrap {
    min-height: 72px;
    display: flex;
    align-items: center;
    gap: 16px;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    color: var(--text);
    font-weight: 700;
}

.brand-mark {
    width: 34px;
    height: 34px;
    border-radius: 9px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    background: linear-gradient(135deg, #2047d1, #1f3bb3);
    font-size: 13px;
    letter-spacing: 0.3px;
}

.main-nav {
    margin-left: auto;
    display: flex;
    align-items: center;
    gap: 14px;
    flex-wrap: wrap;
}

.main-nav > a,
.nav-dropdown > summary {
    text-decoration: none;
    color: var(--text);
    padding: 8px 10px;
    border-radius: 8px;
    list-style: none;
    cursor: pointer;
}

.main-nav > a.active,
.main-nav > a:hover,
.nav-dropdown > summary:hover {
    background: var(--brand-soft);
    color: var(--brand);
}

.nav-dropdown {
    position: relative;
}

.nav-dropdown-menu {
    display: none;
    position: absolute;
    top: 38px;
    left: 0;
    min-width: 280px;
    border: 1px solid var(--line);
    border-radius: 10px;
    background: #fff;
    box-shadow: 0 10px 28px rgba(20, 38, 89, 0.14);
    padding: 6px;
}

.nav-dropdown[open] .nav-dropdown-menu {
    display: block;
}

.nav-dropdown-menu a {
    display: block;
    border-radius: 8px;
    padding: 9px 10px;
    text-decoration: none;
}

.nav-dropdown-menu a:hover {
    background: var(--brand-soft);
}

.menu-toggle {
    display: none;
    margin-left: auto;
    border: 1px solid var(--line);
    border-radius: 8px;
    background: #fff;
    padding: 8px 12px;
    cursor: pointer;
}

.site-main {
    min-height: 68vh;
}

.section {
    background: var(--card);
    border: 1px solid var(--line);
    border-radius: 14px;
    padding: 24px;
    margin: 20px auto;
}

.hero {
    margin-top: 22px;
    padding: 48px 0;
    background: radial-gradient(circle at 20% 20%, #223eaf 0%, #121d37 56%, #0a0f1f 100%);
    color: #fff;
}

.hero h1 {
    margin: 0 0 14px;
    font-size: clamp(28px, 4vw, 48px);
    line-height: 1.15;
}

.hero p {
    margin: 0;
    max-width: 880px;
    color: #d9e4ff;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 24px;
}

.btn {
    display: inline-block;
    text-decoration: none;
    border-radius: 10px;
    padding: 11px 16px;
    border: 1px solid transparent;
    font-weight: 600;
}

.btn-primary {
    background: #2f58ff;
    color: #fff;
}

.btn-secondary {
    border-color: #c9d4ff;
    background: rgba(255, 255, 255, 0.08);
    color: #fff;
}

.grid-2,
.grid-3 {
    display: grid;
    gap: 14px;
}

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

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

.card {
    border: 1px solid var(--line);
    border-radius: 12px;
    background: #fff;
    padding: 16px;
}

.card h3,
.card h4 {
    margin-top: 0;
}

.small {
    color: var(--muted);
    font-size: 14px;
}

.anchor-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 10px;
}

.anchor-nav a {
    text-decoration: none;
    border: 1px solid var(--line);
    border-radius: 20px;
    padding: 6px 12px;
    color: var(--text);
    background: #fff;
}

.anchor-nav a:hover {
    border-color: #9eb0eb;
}

.table-wrap {
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
}

th,
td {
    border: 1px solid var(--line);
    padding: 10px;
    text-align: left;
    vertical-align: top;
}

th {
    background: #eef2ff;
}

.diagram {
    border: 1px dashed #9fb0e6;
    border-radius: 10px;
    padding: 14px;
    background: #f8faff;
    font-weight: 600;
}

.site-footer {
    margin-top: 30px;
    background: var(--bg);
    color: #d7deef;
    padding-top: 26px;
}

.site-footer a {
    color: #fff;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 20px;
}

.footer-title {
    margin: 0 0 8px;
    font-weight: 700;
    color: #fff;
}

.footer-bottom {
    border-top: 1px solid #2b3758;
    margin-top: 16px;
    padding: 14px 0;
    color: #a5b3da;
    font-size: 14px;
}

@media (max-width: 980px) {
    .grid-3 {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 780px) {
    .menu-toggle {
        display: inline-block;
    }

    .main-nav {
        display: none;
        width: 100%;
        margin: 10px 0 12px;
    }

    .main-nav.open {
        display: flex;
        flex-direction: column;
        align-items: stretch;
        gap: 6px;
    }

    .nav-dropdown-menu {
        position: static;
        min-width: 100%;
        margin-top: 6px;
    }

    .grid-2,
    .grid-3,
    .footer-grid {
        grid-template-columns: 1fr;
    }

    .hero-actions .btn {
        width: 100%;
        text-align: center;
    }
}