:root {
    color-scheme: dark;

    --background: #101318;
    --panel: #191e26;
    --input: #11161d;
    --border: #343b47;
    --text: #f3f5f7;
    --muted: #aeb6c2;
    --accent: #ffb454;
    --error: #ff8b8b;
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    min-height: 100vh;
    margin: 0;

    background: var(--background);
    color: var(--text);
    font-family: "Segoe UI", Arial, sans-serif;
    line-height: 1.5;
}

button,
input {
    font: inherit;
}

/* Shared header */

.site-header {
    position: sticky;
    top: 0;
    z-index: 1000;

    background: rgba(16, 19, 24, 0.96);
    border-bottom: 1px solid var(--border);
    backdrop-filter: blur(10px);
}

.site-nav {
    width: min(1100px, calc(100% - 32px));
    min-height: 64px;
    margin: 0 auto;

    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
}

.site-brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;

    color: var(--text);
    font-size: 1.15rem;
    font-weight: 700;
    text-decoration: none;
    white-space: nowrap;
}

.site-brand:hover,
.site-brand:focus-visible {
    color: var(--accent);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 24px;
}

.nav-links a {
    color: var(--muted);
    font-weight: 600;
    text-decoration: none;
}

.nav-links a:hover,
.nav-links a:focus-visible,
.nav-links a[aria-current="page"] {
    color: var(--accent);
}

.menu-toggle {
    display: none;
    width: 44px;
    height: 44px;
    padding: 10px;

    background: transparent;
    border: 1px solid var(--border);
    border-radius: 8px;
    cursor: pointer;
}

.menu-toggle span {
    display: block;
    width: 100%;
    height: 2px;
    margin: 5px 0;

    background: var(--text);
    border-radius: 2px;
    transition:
        transform 0.2s ease,
        opacity 0.2s ease;
}

.menu-toggle[aria-expanded="true"] span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.menu-toggle[aria-expanded="true"] span:nth-child(2) {
    opacity: 0;
}

.menu-toggle[aria-expanded="true"] span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* Shared page layout */

.site-main {
    width: min(1100px, calc(100% - 32px));
    min-height: calc(100vh - 140px);
    margin: 0 auto;
    padding: 48px 0;
}

.content-narrow {
    width: min(720px, 100%);
    margin: 0 auto;
}

.page-heading {
    margin-bottom: 28px;
    text-align: center;
}

.page-heading h1 {
    margin: 0 0 8px;
    font-size: clamp(2rem, 6vw, 3rem);
}

.subtitle {
    color: var(--muted);
    font-size: 1.05rem;
}

.content-card {
    padding: 28px;

    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 14px;
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.22);
}

.content-card h2 {
    margin-top: 0;
}

.content-card p:last-child {
    margin-bottom: 0;
}

.site-footer {
    width: min(1100px, calc(100% - 32px));
    margin: 0 auto;
    padding: 0 0 28px;

    color: var(--muted);
    font-size: 0.85rem;
    text-align: center;
}

/* Mobile navigation */

@media (max-width: 620px) {
    .site-nav {
        position: relative;
    }

    .menu-toggle {
        display: block;
    }

    .nav-links {
        display: none;
        position: absolute;
        top: calc(100% + 8px);
        left: 0;
        right: 0;

        padding: 12px;

        background: var(--panel);
        border: 1px solid var(--border);
        border-radius: 10px;
        box-shadow: 0 14px 30px rgba(0, 0, 0, 0.35);
    }

    .nav-links.is-open {
        display: grid;
        gap: 4px;
    }

    .nav-links a {
        padding: 12px;
        border-radius: 7px;
    }

    .nav-links a:hover,
    .nav-links a:focus-visible,
    .nav-links a[aria-current="page"] {
        background: var(--input);
    }

    .site-main {
        padding: 28px 0;
    }

    .content-card {
        padding: 20px;
    }
}