:root {
    --color-navy: #17242f;
    --color-navy-soft: #1f3241;
    --color-ink: #243746;
    --color-text: #3b4a58;
    --color-muted: #6b7a88;
    --color-light: #f3f6f9;
    --color-border: #d6dde4;
    --color-accent: #d05d4b;
    --color-accent-dark: #b54333;
    --color-sidebar: #ffffff;
    --color-shadow: rgba(15, 27, 38, 0.08);
    --radius-xl: 20px;
    --radius-lg: 16px;
    --radius-md: 12px;
    --max-width: 1200px;
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: "Segoe UI", "Helvetica Neue", Arial, sans-serif;
    background-color: var(--color-light);
    color: var(--color-text);
    line-height: 1.7;
}

a {
    color: var(--color-ink);
    text-decoration: none;
    transition: color 0.2s ease, background-color 0.2s ease, border-color 0.2s ease;
}

a:hover,
a:focus {
    color: var(--color-accent);
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 6vw;
}

.site-header {
    backdrop-filter: blur(12px);
    background-color: rgba(255, 255, 255, 0.92);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: flex-start;
    gap: 1.5rem;
    padding: 1.25rem 0;
}

.logo {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    font-weight: 700;
    font-size: 1.05rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--color-ink);
}

.logo img {
    height: 44px;
    width: auto;
    display: block;
}

.hero {
    background: linear-gradient(135deg, var(--color-navy-soft), var(--color-ink));
    color: #ffffff;
    padding: 5.5rem 0 4.5rem;
    margin-bottom: 2.5rem;
    position: relative;
    overflow: hidden;
}

.hero::after {
    content: "";
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at top right, rgba(255, 255, 255, 0.18), transparent 42%);
    pointer-events: none;
}

.hero .container {
    position: relative;
    z-index: 1;
}

.hero h1 {
    margin: 0;
    font-size: clamp(2.5rem, 5vw, 3.4rem);
    letter-spacing: -0.02em;
}

.hero p {
    max-width: 640px;
    margin: 1.25rem 0 0;
    color: rgba(255, 255, 255, 0.85);
    font-size: 1.1rem;
}

main.content {
    display: flex;
    gap: 2.25rem;
    align-items: flex-start;
    padding: 0 6vw 5rem;
}

.article {
    flex: 3;
    background: #ffffff;
    border-radius: var(--radius-xl);
    box-shadow: 0 18px 34px -32px rgba(23, 36, 47, 0.45), 0 6px 24px var(--color-shadow);
    padding: clamp(1.75rem, 2.5vw, 3rem);
}

.article h1 {
    margin-top: 0;
    font-size: clamp(2rem, 4vw, 2.6rem);
    color: var(--color-navy);
    letter-spacing: -0.01em;
}

.article h2 {
    margin-top: 2.5rem;
    margin-bottom: 1rem;
    font-size: 1.75rem;
    color: var(--color-navy-soft);
}

.article h3 {
    margin-top: 2rem;
    margin-bottom: 0.75rem;
    font-size: 1.35rem;
    color: var(--color-ink);
}

.article p {
    margin: 1.1rem 0;
    color: var(--color-text);
}

.article ul,
.article ol {
    padding-left: 1.4rem;
    margin: 1.25rem 0;
}

.article li {
    margin: 0.5rem 0;
}

.article blockquote {
    margin: 2rem 0;
    padding: 1.25rem 1.75rem;
    background-color: var(--color-light);
    border-left: 4px solid var(--color-accent);
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    color: var(--color-ink);
    font-weight: 500;
}

.article table {
    width: 100%;
    border-collapse: collapse;
    margin: 2rem 0;
    font-size: 0.95rem;
}

.article table th,
.article table td {
    border: 1px solid var(--color-border);
    padding: 0.8rem 1rem;
    text-align: left;
}

.article table thead {
    background-color: var(--color-light);
}

.sidebar {
    flex: 1.25;
    position: sticky;
    top: 6.5rem;
}

.sidebar-card {
    background-color: var(--color-sidebar);
    border-radius: var(--radius-lg);
    box-shadow: 0 16px 40px -32px rgba(23, 36, 47, 0.45), 0 0 0 1px rgba(23, 36, 47, 0.04);
    padding: clamp(1.5rem, 2vw, 2.25rem);
}

.sidebar-card h2 {
    margin-top: 0;
    margin-bottom: 1.25rem;
    font-size: 1.35rem;
    color: var(--color-navy);
}

.sidebar-card ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: grid;
    gap: 0.85rem;
}

.sidebar-card li {
    line-height: 1.4;
}

.sidebar-card li.current a {
    color: var(--color-accent);
    font-weight: 600;
}

.sidebar-card a {
    display: inline-block;
    padding: 0.1rem 0;
}

.site-footer {
    background-color: var(--color-navy);
    color: rgba(255, 255, 255, 0.86);
    padding: 3.5rem 0 2.5rem;
    margin-top: 3rem;
}

.footer-grid {
    display: grid;
    gap: 1.75rem;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.site-footer h3 {
    margin-top: 0;
    color: #ffffff;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    font-size: 0.95rem;
}

.site-footer ul {
    list-style: none;
    padding: 0;
    margin: 0;
    display: grid;
    gap: 0.65rem;
}

.site-footer a {
    color: rgba(255, 255, 255, 0.82);
}

.site-footer a:hover,
.site-footer a:focus {
    color: #ffffff;
}

.footer-bottom {
    margin-top: 2.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid rgba(255, 255, 255, 0.12);
    text-align: center;
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.6);
}

@media (max-width: 1024px) {
    .header-inner {
        flex-direction: column;
        align-items: flex-start;
    }

    .sidebar {
        position: static;
        width: 100%;
    }
}

@media (max-width: 860px) {
    main.content {
        flex-direction: column;
        padding: 0 8vw 4rem;
    }

    .article,
    .sidebar-card {
        border-radius: var(--radius-lg);
    }

    .article {
        box-shadow: 0 12px 24px -20px rgba(23, 36, 47, 0.5), 0 4px 16px var(--color-shadow);
    }
}

@media (max-width: 600px) {
    .container {
        padding: 0 1.5rem;
    }

    main.content {
        padding: 0 1.5rem 3.5rem;
    }

    .article {
        padding: 1.5rem;
    }
}