:root {
    --color-bg: #0b0c10;
    --color-text: #f5f5f5;
    --color-accent: #3fa9f5;
    --color-accent-hover: #63b9ff;
    --color-border: #2b2f36;
    --color-surface: #151821;

    --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;

    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 2rem;
    --space-xl: 4rem;

    --max-width: 1200px;
    --sidebar-width: 250px;

    --radius-sm: 4px;
    --radius-md: 8px;
}

/* Global reset-ish */

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

html {
    scroll-behavior: smooth;
}

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

/* Layout shell */

.site-header,
.site-nav,
.site-footer,
.layout-two-col-right {
    max-width: var(--max-width);
    margin: 0 auto;
    padding-left: var(--space-md);
    padding-right: var(--space-md);
}

.site-header {
    padding-top: var(--space-lg);
    padding-bottom: var(--space-md);
}

.site-nav {
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
    padding-top: var(--space-sm);
    padding-bottom: var(--space-sm);
    margin-bottom: var(--space-lg);
}

/* Skip link */

.skip-link {
    position: absolute;
    left: -999px;
    top: 0;
    padding: var(--space-sm) var(--space-md);
    background-color: var(--color-accent);
    color: #000000;
    text-decoration: none;
    z-index: 1000;
}

.skip-link:focus {
    left: var(--space-md);
    top: var(--space-md);
}

/* Branding */

.branding {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.logo-circle {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 2px solid var(--color-accent);
}

.branding-text {
    display: flex;
    flex-direction: column;
}

.site-name {
    font-weight: 600;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    font-size: 0.9rem;
}

.tagline {
    font-size: 0.85rem;
    color: #c7c7c7;
}

/* Navigation */

.site-nav ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-md);
}

.site-nav a {
    color: var(--color-text);
    text-decoration: none;
    padding: var(--space-xs) 0;
    border-bottom: 2px solid transparent;
}

.site-nav a:focus,
.site-nav a:hover {
    border-bottom-color: var(--color-accent);
    outline: none;
}

/* Two-column layout (right sidebar) */

.layout-two-col-right {
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
    padding-bottom: var(--space-xl);
}

.layout-two-col-right main {
    flex: 1 1 auto;
}

.sidebar {
    flex: 0 0 auto;
}

/* Sidebar */

.sidebar {
    border-left: 1px solid var(--color-border);
    padding-left: var(--space-md);
}

.sidebar-section + .sidebar-section {
    margin-top: var(--space-lg);
}

.sidebar-heading {
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: #c7c7c7;
    margin-bottom: var(--space-sm);
}

.sidebar-list {
    list-style: none;
    padding-left: 0;
    margin: 0;
}

.sidebar-list li + li {
    margin-top: var(--space-xs);
}

.sidebar a {
    color: var(--color-accent);
    text-decoration: none;
}

.sidebar a:hover,
.sidebar a:focus {
    text-decoration: underline;
}

/* Main content */

main {
    outline: none;
}

.section {
    margin-bottom: var(--space-xl);
}

.section:last-of-type {
    margin-bottom: 0;
}

.hero {
    margin-bottom: var(--space-xl);
}

.hero h1 {
    font-size: 1.8rem;
    margin-bottom: var(--space-md);
}

.hero p {
    max-width: 40rem;
}

/* Lists alignment rule */

main ul,
main ol {
    padding-left: 1.6rem;
}

/* Cards and grids */

.grid {
    display: grid;
    gap: var(--space-md);
}

.grid-two {
    grid-template-columns: 1fr;
}

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

/* Buttons */

.button {
    display: inline-block;
    padding: 0.6rem 1.2rem;
    border-radius: var(--radius-sm);
    border: 1px solid transparent;
    font-size: 0.95rem;
    cursor: pointer;
    text-decoration: none;
}

.button.primary {
    background-color: var(--color-accent);
    color: #000000;
}

.button.primary:hover,
.button.primary:focus {
    background-color: var(--color-accent-hover);
    outline: 2px solid var(--color-accent-hover);
    outline-offset: 2px;
}

/* Forms */

.contact-form {
    max-width: 32rem;
}

.form-group {
    margin-bottom: var(--space-md);
}

.form-group label {
    display: block;
    margin-bottom: var(--space-xs);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: var(--space-sm);
    border-radius: var(--radius-sm);
    border: 1px solid var(--color-border);
    background-color: #0f1118;
    color: var(--color-text);
    font-family: var(--font-body);
    font-size: 1rem;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

/* Footer */

.site-footer {
    border-top: 1px solid var(--color-border);
    padding-top: var(--space-md);
    padding-bottom: var(--space-lg);
    font-size: 0.85rem;
    color: #c7c7c7;
}

/* Links */

a {
    color: var(--color-accent);
}

a:hover,
a:focus {
    text-decoration: underline;
}

/* Responsive */

@media (min-width: 768px) {
    .layout-two-col-right {
        flex-direction: row;
        align-items: flex-start;
    }

    .layout-two-col-right main {
        flex: 1 1 auto;
    }

    .layout-two-col-right .sidebar {
        flex: 0 0 var(--sidebar-width);
    }

    .grid-two {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}