/* ==================================================================
   Base / Design tokens
   ================================================================== */
:root {
    --color-bg: #ffffff;
    --color-text: #1a1a2e;
    --color-muted: #6b7280;
    --color-primary: #4f46e5;
    --color-primary-dark: #4338ca;
    --color-border: #e5e7eb;
    --color-surface: #f9fafb;

    --font-base: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;

    --radius: 8px;
    --max-width: 1120px;
    --transition: 0.2s ease;
}

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

html {
    -webkit-text-size-adjust: 100%;
}

body {
    margin: 0;
    font-family: var(--font-base);
    color: var(--color-text);
    background: var(--color-bg);
    line-height: 1.6;
    font-size: 16px;
}

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

a {
    color: var(--color-primary);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

h1, h2, h3, h4 {
    line-height: 1.25;
    margin: 0 0 0.6em;
}

p {
    margin: 0 0 1em;
}

.container {
    max-width: var(--max-width);
    margin-inline: auto;
    padding-inline: 1.25rem;
}

.skip-link {
    position: absolute;
    left: -9999px;
    top: 0;
    background: var(--color-primary);
    color: #fff;
    padding: 0.5rem 1rem;
    z-index: 1000;
}

.skip-link:focus {
    left: 0.5rem;
    top: 0.5rem;
}

/* ==================================================================
   Header / Navigation
   ================================================================== */
.site-header {
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    background: var(--color-bg);
    z-index: 100;
}

.site-header__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-block: 1rem;
}

.brand {
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--color-text);
    text-decoration: none;
}

.primary-nav ul {
    list-style: none;
    display: flex;
    gap: 1.5rem;
    margin: 0;
    padding: 0;
}

.primary-nav a {
    color: var(--color-text);
    font-weight: 500;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 4px;
    width: 40px;
    height: 40px;
    background: none;
    border: none;
    cursor: pointer;
}

.nav-toggle span {
    display: block;
    height: 2px;
    background: var(--color-text);
    border-radius: 2px;
}

/* ==================================================================
   Breadcrumbs
   ================================================================== */
.breadcrumbs {
    padding-block: 1rem;
}

.breadcrumbs ol {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
    padding: 0;
    margin: 0;
    font-size: 0.875rem;
    color: var(--color-muted);
}

.breadcrumbs li:not(:last-child)::after {
    content: "/";
    margin-left: 0.4rem;
    color: var(--color-border);
}

/* ==================================================================
   Main content
   ================================================================== */
main,
#main-content {
    display: block;
}

.section {
    padding-block: 3rem;
}

.card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 1.5rem;
}

.btn {
    display: inline-block;
    padding: 0.7rem 1.4rem;
    background: var(--color-primary);
    color: #fff;
    border-radius: var(--radius);
    font-weight: 600;
    text-decoration: none;
    transition: background var(--transition);
}

.btn:hover {
    background: var(--color-primary-dark);
    text-decoration: none;
}

.error-page {
    text-align: center;
    padding-block: 5rem;
}

.error-page h1 {
    font-size: 4rem;
    color: var(--color-primary);
}

/* ==================================================================
   Footer
   ================================================================== */
.site-footer {
    border-top: 1px solid var(--color-border);
    margin-top: 3rem;
    color: var(--color-muted);
    font-size: 0.9rem;
}

.site-footer__inner {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: space-between;
    padding-block: 1.5rem;
}

.footer-links {
    list-style: none;
    display: flex;
    gap: 1rem;
    margin: 0;
    padding: 0;
}

/* ==================================================================
   Responsive
   ================================================================== */
@media (max-width: 768px) {
    .nav-toggle {
        display: flex;
    }

    .primary-nav {
        display: none;
        width: 100%;
    }

    .primary-nav.is-open {
        display: block;
    }

    .primary-nav ul {
        flex-direction: column;
        gap: 0;
        padding-block: 0.5rem;
    }

    .primary-nav li {
        border-top: 1px solid var(--color-border);
    }

    .primary-nav a {
        display: block;
        padding: 0.75rem 0;
    }

    .site-header__inner {
        flex-wrap: wrap;
    }
}