/*
 * learn.css
 * Site-wide styles for OfficeSeries Learn — enterprise documentation theme.
 * Page-specific hub styles live in learn-hubs.css.
 * Index card styles live in learn-index.css.
 *
 * Design system tokens
 * --os-font:       System font stack (no external fonts)
 * --os-text:       #1d1d1f   (near-black, high contrast)
 * --os-text-muted: #6e6e73   (secondary text)
 * --os-primary:    #0066cc   (accessible blue, 4.5:1 on white)
 * --os-primary-hv: #004999   (hover blue)
 * --os-surface:    #ffffff
 * --os-bg:         #f5f5f7   (warm grey canvas)
 * --os-border:     #d2d2d7
 * --os-radius:     8px
 */

:root {
    --os-font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Helvetica Neue', Arial, sans-serif;
    --os-text: #1d1d1f;
    --os-text-muted: #6e6e73;
    --os-primary: #0066cc;
    --os-primary-hover: #004999;
    --os-surface: #ffffff;
    --os-bg: #ffffff;
    --os-border: #d2d2d7;
    --os-radius: 8px;
}

/* ────────────── Base ────────────── */

body {
    font-family: var(--os-font);
    font-size: 16px;
    line-height: 1.7;
    color: var(--os-text);
    background-color: var(--os-bg);
    margin: 0;
    padding: 0;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

@media (min-width: 768px) {
    .container-md-80 {
        width: 80%;
        margin-left: auto;
        margin-right: auto;
    }
}

@media (min-width: 1800px) {
    .container-md-80 {
        width: 75%;
    }
}

/* ────────────── Typography ────────────── */

a {
    color: var(--os-primary);
    text-decoration: none;
    transition: color 0.15s ease;
}

a:hover {
    color: var(--os-primary-hover);
    text-decoration: underline;
    text-underline-offset: 2px;
}

code {
    font-family: 'SF Mono', 'Cascadia Code', 'Fira Code', 'Consolas', monospace;
    font-size: 0.875em;
    background-color: rgba(0, 0, 0, 0.04);
    border-radius: 4px;
    padding: 0.15em 0.4em;
}

pre {
    background-color: #f8f8fa;
    border: 1px solid var(--os-border);
    border-radius: var(--os-radius);
    padding: 1.25em;
    overflow-x: auto;
    font-size: 0.875em;
    line-height: 1.6;
}

pre code {
    background: none;
    padding: 0;
    border-radius: 0;
}

/* ────────────── Header ────────────── */

.learn-header {
    background: var(--os-surface);
    border-bottom: 1px solid var(--os-border);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

.learn-brand {
    color: var(--os-text);
    font-size: 1.375rem;
    font-weight: 600;
    font-family: var(--os-font);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 0.625rem;
}

.learn-brand:hover {
    color: var(--os-text);
    text-decoration: none;
}

.learn-brand img {
    height: 28px;
    width: 28px;
}

.learn-brand-divider {
    color: var(--os-border);
    font-weight: 300;
    font-size: 1.5rem;
    margin: 0 0.25rem;
    user-select: none;
}

.learn-brand-sub {
    color: var(--os-text);
    font-size: 1.25rem;
    font-weight: 500;
    font-family: var(--os-font);
    text-decoration: none;
}

.learn-brand-sub:hover {
    color: var(--os-primary);
    text-decoration: none;
}

.learn-nav-link {
    font-family: var(--os-font);
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--os-text);
    padding: 0.5rem 0.75rem;
    transition: color 0.15s ease;
}

.learn-nav-link:hover {
    color: var(--os-primary);
}

.learn-nav-cta {
    font-family: var(--os-font);
    font-size: 0.875rem;
    font-weight: 600;
    padding: 0.5rem 1.25rem;
    border-radius: 6px;
}

/* ────────────── Footer ────────────── */

.learn-footer {
    background: var(--os-surface);
    border-top: 1px solid var(--os-border);
    padding: 2rem 0;
    color: var(--os-text-muted);
    font-size: 0.875rem;
}

.learn-footer a {
    color: var(--os-text);
    font-weight: 500;
    transition: color 0.15s ease;
}

.learn-footer a:hover {
    color: var(--os-primary);
}

/* ────────────── Utility ────────────── */

.sticky-header {
    position: sticky;
    top: 0;
    z-index: 1020;
    background-color: var(--os-surface);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
}