@import url("https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&display=swap");

:root {
    --surface: #f8f9fa;
    --surface-container-low: #f1f4f6;
    --surface-container-lowest: #ffffff;
    --surface-container-high: #e2e9ec;
    --surface-container-highest: #dbe4e7;
    --inverse-surface: #0c0f10;
    --on-surface: #2b3437;
    --on-surface-variant: #586064;
    --primary: #565e74;
    --primary-dim: #4a5268;
    --primary-fixed: #dae2fd;
    --primary-fixed-dim: #ccd4ee;
    --on-primary: #f7f7ff;
    --on-primary-container: #4a5167;
    --tertiary-container: #e3dbfd;
    --on-tertiary-container: #514d68;
    --error-container: #fe8983;
    --on-error-container: #752121;
    --outline-variant: #abb3b7;
    --shadow: 0 20px 40px rgba(43, 52, 55, 0.05);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Inter", "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
    color: var(--on-surface);
    background:
        radial-gradient(circle at -5% -12%, rgba(203, 212, 238, 0.55) 0, rgba(203, 212, 238, 0) 44%),
        radial-gradient(circle at 102% 5%, rgba(227, 219, 253, 0.45) 0, rgba(227, 219, 253, 0) 38%),
        var(--surface);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

header {
    position: sticky;
    top: 0;
    z-index: 20;
    background: rgba(248, 249, 250, 0.7);
    color: var(--on-surface);
    padding: 18px 20px;
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border: 0;
    box-shadow: 0 10px 24px rgba(43, 52, 55, 0.04);
}

.home-page header,
.chapter-page header {
    position: relative !important;
    padding-right: 260px !important;
}

.home-page header h1,
.chapter-page header h1 {
    font-size: clamp(1rem, 1.8vw, 1.4rem) !important;
}

header h1 {
    margin: 0;
    font-size: clamp(1.4rem, 2.6vw, 2rem);
    letter-spacing: -0.03em;
    color: #000;
    display: inline-flex;
    align-items: center;
    gap: 10px;
}

header h1::before {
    content: "";
    width: 22px;
    height: 22px;
    flex: 0 0 22px;
    background: url("security-logo.svg") center/contain no-repeat;
}

header p {
    margin: 6px 0 0;
    opacity: 1;
    font-size: 0.95rem;
    color: var(--on-surface-variant);
}

.mobile-menu {
    display: none;
}

.home-page .mobile-menu,
.chapter-page .mobile-menu {
    position: absolute !important;
    top: 14px !important;
    right: 14px !important;
    z-index: 30 !important;
}

.home-page .mobile-menu summary,
.chapter-page .mobile-menu summary {
    font-size: 0.72rem !important;
    padding: 6px 10px !important;
}

.mobile-menu summary {
    list-style: none;
}

.mobile-menu summary::-webkit-details-marker {
    display: none;
}

nav {
    margin-top: 14px;
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.home-page nav,
.chapter-page nav {
    position: absolute !important;
    top: 14px !important;
    right: 14px !important;
    margin-top: 0 !important;
    justify-content: flex-end !important;
    gap: 4px !important;
    overflow-x: auto !important;
    padding-bottom: 0 !important;
    scrollbar-width: thin;
}

nav a {
    text-decoration: none;
    color: var(--on-primary-container);
    border: 0;
    border-radius: 999px;
    padding: 8px 14px;
    font-size: 0.82rem;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    background: rgba(248, 249, 250, 0.74);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    transition: transform 0.2s ease, background 0.2s ease;
}

.home-page nav a,
.chapter-page nav a {
    text-transform: none !important;
    letter-spacing: 0 !important;
    font-size: 0.68rem !important;
    padding: 5px 8px !important;
    border-radius: 5px !important;
    color: #1f2d33 !important;
    background: #ffffff !important;
    border: 1px solid #dbe4e7 !important;
    box-shadow: none !important;
    white-space: nowrap !important;
}

nav a:hover {
    background: linear-gradient(135deg, var(--primary), var(--primary-dim));
    color: var(--on-primary);
    transform: translateY(-1px);
}

.home-page nav a:hover,
.chapter-page nav a:hover {
    background: linear-gradient(135deg, #0f5d79, #2a7d9d) !important;
    color: #fff !important;
    transform: none !important;
}

main {
    max-width: 1220px;
    margin: 26px auto;
    padding: 0 18px 34px;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 16px;
}

.card {
    background: var(--surface-container-lowest);
    border: none;
    border-radius: 14px;
    padding: 32px;
    box-shadow: var(--shadow);
}

.card h2,
.card h3 {
    margin-top: 0;
    margin-bottom: 8px;
    letter-spacing: -0.015em;
}

.card p,
.card li {
    color: var(--on-surface-variant);
    font-size: 0.97rem;
    line-height: 1.6;
}

.section-title {
    margin: 14px 0 16px;
    font-size: clamp(2.3rem, 5vw, 4.25rem);
    letter-spacing: -0.04em;
    color: #000;
    line-height: 0.95;
}

.link-list {
    padding-left: 18px;
    margin: 8px 0 0;
}

.link-list a {
    color: var(--primary);
}

.tool-card {
    display: grid;
    grid-template-columns: 84px 1fr;
    gap: 12px;
    align-items: center;
    padding: 20px;
    border-radius: 12px;
    background: var(--surface-container-low);
}

.tool-card img {
    width: 84px;
    height: 84px;
    object-fit: contain;
    border-radius: 10px;
    border: 0;
    background: #fff;
}

.corner-logo {
    display: none !important;
}

.tag {
    display: inline-block;
    font-size: 0.78rem;
    border-radius: 999px;
    padding: 4px 9px;
    margin-bottom: 8px;
}

.tag.warn {
    color: var(--on-error-container);
    background: var(--error-container);
}

.tag.ok {
    color: var(--on-tertiary-container);
    background: var(--tertiary-container);
}

.hero {
    position: relative;
    overflow: hidden;
}

.hero::after {
    content: "";
    position: absolute;
    inset: auto -80px -80px auto;
    width: 260px;
    height: 260px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(218, 226, 253, 0.28) 0, rgba(218, 226, 253, 0) 72%);
    pointer-events: none;
}

.hero-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 16px;
}

.dashboard-card {
    min-height: 180px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.dashboard-card a {
    align-self: flex-start;
    padding: 10px 14px;
    border-radius: 999px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dim));
    color: var(--on-primary);
    text-decoration: none;
    box-shadow: 0 10px 20px rgba(74, 82, 104, 0.14);
}

.dashboard-card a:hover {
    transform: translateY(-1px);
}

.meta {
    font-size: 0.86rem;
    color: var(--on-surface-variant);
    margin: 4px 0 12px;
}

.toc-title {
    margin-bottom: 4px;
    font-weight: 700;
    font-size: 0.82rem;
    color: var(--on-surface-variant);
    letter-spacing: 0.06em;
    text-transform: uppercase;
}

.presenter-note {
    border-left: 2px solid var(--primary-fixed-dim);
    background: var(--tertiary-container);
    padding: 14px 14px;
    border-radius: 12px;
    color: var(--on-tertiary-container);
    font-size: 0.92rem;
    margin-top: 10px;
}

.quick-links {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 10px;
}

.quick-links a {
    text-decoration: none;
    color: var(--primary);
    border: 0;
    background: var(--surface-container-high);
    border-radius: 999px;
    padding: 6px 11px;
    font-size: 0.85rem;
}

footer {
    max-width: 1220px;
    margin: 0 auto 20px;
    padding: 0 18px;
    color: var(--on-surface-variant);
    font-size: 0.86rem;
}

body {
    padding-bottom: 92px;
}

.page-pager {
    position: fixed;
    left: 0;
    right: 0;
    bottom: 14px;
    z-index: 60;
    display: flex;
    justify-content: center;
    pointer-events: none;
}

.page-pager-inner {
    width: min(980px, calc(100% - 20px));
    display: flex;
    justify-content: space-between;
    gap: 10px;
    padding: 8px;
    border-radius: 14px;
    background: rgba(255, 255, 255, 0.84);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    box-shadow: 0 14px 26px rgba(43, 52, 55, 0.12);
    pointer-events: auto;
}

.page-pager a {
    text-decoration: none;
    border-radius: 999px;
    padding: 9px 14px;
    font-size: 0.82rem;
    font-weight: 700;
    letter-spacing: 0.01em;
    color: #fff;
    background: linear-gradient(135deg, #0f5d79, #2a7d9d);
    box-shadow: 0 8px 16px rgba(15, 93, 121, 0.22);
}

.page-pager a:hover {
    filter: brightness(1.06);
}

/* Sovereign Cipher chapter layout: intentional asymmetry with a metadata rail. */
.chapter-page .slide {
    display: grid;
    grid-template-columns: 170px minmax(0, 1fr);
    gap: 24px;
}

.chapter-page .slide > * {
    grid-column: 2;
}

.chapter-page .slide > .meta {
    grid-column: 1;
    grid-row: 1 / span 2;
    margin: 2px 0 0;
    font-size: 0.76rem;
    letter-spacing: 0.07em;
    text-transform: uppercase;
}

.chapter-page .slide > h3 {
    margin: 0 0 2px;
    font-size: clamp(1.22rem, 2.8vw, 1.72rem);
    letter-spacing: -0.02em;
    color: #000;
}

.chapter-page .slide > p,
.chapter-page .slide > ul,
.chapter-page .slide > div,
.chapter-page .slide > span,
.chapter-page .slide > article {
    max-width: 720px;
}

.chapter-page .slide > ul {
    margin-top: 4px;
}

.chapter-page .slide > ul li {
    margin-bottom: 8px;
}

.chapter-page .quick-links a {
    border: 0 !important;
}

.chapter-page a:focus-visible,
.home-page a:focus-visible {
    outline: 2px solid rgba(171, 179, 183, 0.15);
    outline-offset: 2px;
    border-radius: 10px;
}

.chapter-page input,
.chapter-page textarea,
.chapter-page select {
    background: var(--surface-container-low);
    border: 0;
    border-radius: 10px;
}

.chapter-page input:focus,
.chapter-page textarea:focus,
.chapter-page select:focus {
    background: var(--surface-container-lowest);
    outline: 2px solid rgba(171, 179, 183, 0.15);
}

@media (max-width: 700px) {
    header {
        padding-right: 90px;
    }

    .home-page header,
    .chapter-page header {
        padding-right: 90px;
    }

    header nav {
        display: none;
    }

    .mobile-menu {
        display: block;
    }

    .home-page nav,
    .chapter-page nav {
        position: static;
        justify-content: flex-start;
        margin-top: 10px;
        overflow-x: auto;
        padding-bottom: 2px;
    }

    .mobile-menu summary {
        cursor: pointer;
        border: 0;
        border-radius: 999px;
        padding: 8px 12px;
        font-size: 0.8rem;
        letter-spacing: 0.04em;
        text-transform: uppercase;
        background: var(--surface-container-lowest);
        color: #000;
        box-shadow: 0 10px 24px rgba(43, 52, 55, 0.12);
    }

    .mobile-menu-panel {
        margin-top: 8px;
        min-width: 220px;
        max-width: calc(100vw - 28px);
        border-radius: 12px;
        background: var(--surface-container-lowest);
        box-shadow: 0 20px 32px rgba(43, 52, 55, 0.16);
        overflow: hidden;
    }

    .mobile-menu-panel a {
        display: block;
        padding: 11px 14px;
        color: var(--on-surface);
        text-decoration: none;
        font-size: 0.9rem;
        border-top: 1px solid rgba(171, 179, 183, 0.2);
        white-space: normal;
    }

    .mobile-menu-panel a:first-child {
        border-top: 0;
    }

    .mobile-menu-panel a:hover {
        background: var(--surface-container-low);
    }

    .tool-card {
        grid-template-columns: 1fr;
    }

    .tool-card img {
        width: 72px;
        height: 72px;
    }

    .chapter-page .slide {
        grid-template-columns: 1fr;
        gap: 10px;
        padding: 24px;
    }

    .chapter-page .slide > * {
        grid-column: 1;
    }

    .chapter-page .slide > .meta {
        grid-row: auto;
    }

    .card {
        padding: 24px;
    }

    body {
        padding-bottom: 102px;
    }

    .page-pager {
        bottom: 10px;
    }

    .page-pager-inner {
        width: calc(100% - 14px);
        padding: 6px;
    }

    .page-pager a {
        flex: 1 1 0;
        text-align: center;
        font-size: 0.78rem;
        padding: 9px 10px;
    }
}

@media (prefers-reduced-motion: no-preference) {
    .card,
    nav a,
    .dashboard-card a,
    .quick-links a {
        transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
    }

    .card:hover {
        transform: translateY(-2px);
        box-shadow: 0 26px 42px rgba(43, 52, 55, 0.08);
    }
}

@media (max-width: 820px) {
    .visual-grid {
        display: grid !important;
        grid-auto-flow: column !important;
        grid-auto-columns: minmax(82%, 1fr) !important;
        grid-template-columns: none !important;
        overflow-x: auto !important;
        overscroll-behavior-x: contain;
        scroll-snap-type: x mandatory;
        gap: 10px !important;
        padding-bottom: 6px;
        -webkit-overflow-scrolling: touch;
    }

    .visual-grid::-webkit-scrollbar {
        height: 6px;
    }

    .visual-card {
        min-width: 0;
        scroll-snap-align: start;
    }
}