:root {
    --primary: #0b3154;
    --primary-2: #123e68;
    --secondary: #29b3b3;
    --secondary-dark: #1b9797;
    --background: #f7fafc;
    --surface: #ffffff;
    --text: #17324a;
    --muted: #6d7f8f;
    --border: #dce7ec;
    --soft: #edf7f7;
    --warning-bg: #fff8e8;
    --warning-border: #f1c968;
    --shadow: 0 10px 30px rgba(11, 49, 84, 0.08);
    --radius: 18px;
    --container: 1180px;
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: Tahoma, Arial, sans-serif;
    color: var(--text);
    background: var(--background);
    line-height: 1.8;
}

a {
    color: inherit;
    text-decoration: none;
}

img {
    max-width: 100%;
    display: block;
}

button,
input {
    font: inherit;
}

.container {
    width: min(calc(100% - 32px), var(--container));
    margin-inline: auto;
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(255, 255, 255, 0.96);
    border-bottom: 1px solid var(--border);
    backdrop-filter: blur(12px);
}

.header-inner {
    min-height: 78px;
    display: flex;
    align-items: center;
    gap: 28px;
}

.brand {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-inline-end: auto;
}

.brand img {
    width: 58px;
    height: 58px;
    object-fit: contain;
    border-radius: 14px;
}

.brand-text strong {
    display: block;
    color: var(--primary);
    font-size: 18px;
}

.brand-text span {
    color: var(--muted);
    font-size: 13px;
}

.main-nav {
    display: flex;
    align-items: center;
    gap: 22px;
}

.main-nav a {
    color: var(--primary);
    font-weight: 700;
    font-size: 15px;
}

.main-nav a:hover,
.main-nav a.active {
    color: var(--secondary-dark);
}

.platform-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 16px;
    border-radius: 12px;
    background: var(--primary);
    color: #fff;
    font-weight: 700;
}

.mobile-menu-btn {
    display: none;
    border: 0;
    background: transparent;
    font-size: 26px;
    color: var(--primary);
    cursor: pointer;
}

.hero {
    padding: 76px 0 56px;
    background:
        radial-gradient(circle at 15% 20%, rgba(41, 179, 179, 0.16), transparent 28%),
        linear-gradient(180deg, #ffffff 0%, #f7fafc 100%);
    border-bottom: 1px solid var(--border);
}

.hero-content {
    max-width: 820px;
    margin: 0 auto;
    text-align: center;
}

.eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 14px;
    padding: 6px 12px;
    border-radius: 999px;
    background: var(--soft);
    color: var(--secondary-dark);
    font-size: 14px;
    font-weight: 700;
}

.hero h1 {
    margin: 0 0 14px;
    color: var(--primary);
    font-size: clamp(32px, 5vw, 54px);
    line-height: 1.25;
}

.hero p {
    margin: 0 auto 28px;
    max-width: 680px;
    color: var(--muted);
    font-size: 18px;
}

.search-box {
    position: relative;
    max-width: 720px;
    margin: 0 auto;
}

.search-box input {
    width: 100%;
    height: 62px;
    padding: 0 58px 0 20px;
    border: 1px solid var(--border);
    border-radius: 18px;
    background: #fff;
    color: var(--text);
    box-shadow: var(--shadow);
    outline: none;
}

.search-box input:focus {
    border-color: var(--secondary);
    box-shadow: 0 0 0 4px rgba(41, 179, 179, 0.12);
}

.search-icon {
    position: absolute;
    top: 50%;
    right: 20px;
    transform: translateY(-50%);
    color: var(--secondary-dark);
    font-size: 22px;
}

.search-results {
    position: absolute;
    inset-inline: 0;
    top: calc(100% + 10px);
    z-index: 20;
    display: none;
    max-height: 360px;
    overflow: auto;
    background: #fff;
    border: 1px solid var(--border);
    border-radius: 16px;
    box-shadow: var(--shadow);
    text-align: right;
}

.search-results.show {
    display: block;
}

.search-result-item {
    display: block;
    padding: 14px 18px;
    border-bottom: 1px solid var(--border);
}

.search-result-item:last-child {
    border-bottom: 0;
}

.search-result-item:hover {
    background: var(--soft);
}

.search-result-item strong {
    display: block;
    color: var(--primary);
}

.search-result-item span {
    color: var(--muted);
    font-size: 13px;
}

.section {
    padding: 64px 0;
}

.section-head {
    display: flex;
    align-items: end;
    justify-content: space-between;
    gap: 20px;
    margin-bottom: 28px;
}

.section-head h2 {
    margin: 0;
    color: var(--primary);
    font-size: 30px;
}

.section-head p {
    margin: 6px 0 0;
    color: var(--muted);
}

.cards-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 18px;
}

.category-card {
    min-height: 210px;
    padding: 24px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: 0 6px 20px rgba(11, 49, 84, 0.05);
    transition: transform .2s ease, box-shadow .2s ease, border-color .2s ease;
}

.category-card:hover {
    transform: translateY(-5px);
    border-color: rgba(41, 179, 179, 0.6);
    box-shadow: var(--shadow);
}

.category-icon {
    width: 48px;
    height: 48px;
    display: grid;
    place-items: center;
    margin-bottom: 18px;
    border-radius: 14px;
    background: var(--soft);
    color: var(--secondary-dark);
    font-size: 24px;
}

.category-card h3 {
    margin: 0 0 8px;
    color: var(--primary);
    font-size: 20px;
}

.category-card p {
    margin: 0 0 18px;
    color: var(--muted);
    font-size: 14px;
}

.card-meta {
    color: var(--secondary-dark);
    font-size: 13px;
    font-weight: 700;
}

.popular-list {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 14px;
}

.popular-item {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 18px;
    background: #fff;
    border: 1px solid var(--border);
    border-radius: 16px;
}

.popular-number {
    flex: 0 0 38px;
    width: 38px;
    height: 38px;
    display: grid;
    place-items: center;
    border-radius: 12px;
    background: var(--primary);
    color: #fff;
    font-weight: 700;
}

.popular-item strong {
    display: block;
    color: var(--primary);
}

.popular-item span {
    color: var(--muted);
    font-size: 13px;
}

.breadcrumb {
    padding: 22px 0;
    color: var(--muted);
    font-size: 14px;
}

.breadcrumb a {
    color: var(--secondary-dark);
}

.page-hero {
    padding: 42px 0;
    background: linear-gradient(135deg, var(--primary), var(--primary-2));
    color: #fff;
}

.page-hero h1 {
    margin: 0 0 10px;
    font-size: clamp(30px, 4vw, 44px);
}

.page-hero p {
    margin: 0;
    max-width: 740px;
    color: rgba(255,255,255,.78);
}

.content-layout {
    display: grid;
    grid-template-columns: 280px minmax(0, 1fr);
    gap: 28px;
    align-items: start;
    padding: 40px 0 72px;
}

.sidebar {
    position: sticky;
    top: 104px;
    padding: 20px;
    background: #fff;
    border: 1px solid var(--border);
    border-radius: 16px;
}

.sidebar h3 {
    margin: 0 0 14px;
    color: var(--primary);
}

.sidebar a {
    display: block;
    padding: 10px 12px;
    border-radius: 10px;
    color: var(--muted);
    font-size: 14px;
}

.sidebar a:hover,
.sidebar a.active {
    background: var(--soft);
    color: var(--secondary-dark);
    font-weight: 700;
}

.content-card {
    padding: 32px;
    background: #fff;
    border: 1px solid var(--border);
    border-radius: 18px;
}

.content-card h2,
.content-card h3 {
    color: var(--primary);
}

.article-summary {
    margin-bottom: 28px;
    padding: 18px;
    background: var(--soft);
    border-right: 4px solid var(--secondary);
    border-radius: 12px;
}

.steps {
    display: grid;
    gap: 26px;
}

.step {
    padding: 24px;
    border: 1px solid var(--border);
    border-radius: 16px;
}

.step-number {
    display: inline-grid;
    place-items: center;
    width: 38px;
    height: 38px;
    margin-bottom: 12px;
    border-radius: 12px;
    background: var(--secondary);
    color: #fff;
    font-weight: 700;
}

.image-placeholder {
    min-height: 280px;
    display: grid;
    place-items: center;
    margin-top: 18px;
    border: 2px dashed var(--border);
    border-radius: 14px;
    background: var(--background);
    color: var(--muted);
}

.notice {
    margin: 26px 0;
    padding: 18px 20px;
    border: 1px solid var(--warning-border);
    border-right: 4px solid var(--warning-border);
    border-radius: 14px;
    background: var(--warning-bg);
}

.accordion {
    border-top: 1px solid var(--border);
}

.accordion-item {
    border-bottom: 1px solid var(--border);
}

.accordion-button {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 18px 0;
    border: 0;
    background: transparent;
    color: var(--primary);
    text-align: right;
    font-weight: 700;
    cursor: pointer;
}

.accordion-button::after {
    content: "+";
    color: var(--secondary-dark);
    font-size: 24px;
}

.accordion-item.open .accordion-button::after {
    content: "−";
}

.accordion-content {
    display: none;
    padding: 0 0 18px;
    color: var(--muted);
}

.accordion-item.open .accordion-content {
    display: block;
}

.article-nav {
    display: grid;
    grid-template-columns: repeat(2, minmax(0,1fr));
    gap: 14px;
    margin-top: 32px;
}

.article-nav a {
    padding: 18px;
    border: 1px solid var(--border);
    border-radius: 14px;
    background: #fff;
}

.article-nav small {
    display: block;
    color: var(--muted);
}

.article-nav strong {
    color: var(--primary);
}

.site-footer {
    padding: 34px 0;
    border-top: 1px solid var(--border);
    background: #fff;
    color: var(--muted);
}

.footer-inner {
    display: flex;
    justify-content: space-between;
    gap: 20px;
    align-items: center;
}

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

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

    .sidebar {
        position: static;
    }

    .main-nav,
    .platform-link {
        display: none;
    }

    .mobile-menu-btn {
        display: block;
    }

    .main-nav.open {
        position: absolute;
        top: 78px;
        right: 16px;
        left: 16px;
        display: grid;
        gap: 0;
        padding: 12px;
        background: #fff;
        border: 1px solid var(--border);
        border-radius: 14px;
        box-shadow: var(--shadow);
    }

    .main-nav.open a {
        padding: 12px;
    }
}

@media (max-width: 640px) {
    .hero {
        padding: 52px 0 40px;
    }

    .cards-grid,
    .popular-list,
    .article-nav {
        grid-template-columns: 1fr;
    }

    .section {
        padding: 44px 0;
    }

    .content-card {
        padding: 22px;
    }

    .brand-text span {
        display: none;
    }

    .footer-inner {
        align-items: flex-start;
        flex-direction: column;
    }
}

.article-image {
    margin-top: 18px;
    overflow: hidden;
    border: 1px solid var(--border);
    border-radius: 14px;
    background: #fff;
    box-shadow: 0 8px 24px rgba(11, 49, 84, 0.07);
}
.article-image img {
    width: 100%;
    height: auto;
}
.image-caption {
    margin: 0;
    padding: 12px 16px;
    border-top: 1px solid var(--border);
    color: var(--muted);
    font-size: 13px;
}
.field-list {
    display: grid;
    gap: 10px;
    margin: 16px 0;
}
.field-list div {
    padding: 12px 14px;
    border: 1px solid var(--border);
    border-radius: 12px;
    background: var(--background);
}
.field-list strong {
    color: var(--primary);
}