:root {

    /* LAYOUT */
    --header-height: 60px;
    --container-width: 1180px;
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;

    /* Backgrounds */
    --colour-background: 8, 11, 18;
    --colour-surface: 17, 22, 33;
    --colour-surface-hover: 26, 33, 48;
    --colour-surface-raised: 22, 28, 42;

    /* Text */
    --colour-text: 236, 240, 245;
    --colour-text-secondary: 156, 168, 189;
    --colour-text-muted: 108, 120, 140;

    /* Borders */
    --colour-border: 39, 48, 66;
    --colour-border-strong: 58, 70, 94;

    /* Brand: blue for actions, amber for highlights/signal accents */
    --colour-primary: 56, 178, 255;
    --colour-primary-hover: 100, 199, 255;
    --colour-primary-active: 33, 140, 214;
    --colour-primary-subtle: 56, 178, 255;

    --colour-accent: 245, 176, 65;
    --colour-accent-hover: 250, 194, 100;

    /* Status */
    --colour-success: 60, 200, 130;
    --colour-warning: 240, 180, 60;
    --colour-error: 240, 95, 95;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.35);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.35);
    --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.45);
}

* {
    box-sizing: border-box;
}

html {
    color-scheme: dark;
}

body {
    margin: 0;
    overflow-x: hidden;
    color: rgb(var(--colour-text));
    font-family: system-ui, -apple-system, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
    background-color: rgb(var(--colour-background));
    line-height: 1.55;
    -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
    line-height: 1.2;
    font-weight: 700;
    margin: 0 0 0.5em;
}

h1 { font-size: clamp(2rem, 1.5rem + 2vw, 3.25rem); letter-spacing: -0.02em; }
h2 { font-size: clamp(1.5rem, 1.3rem + 1vw, 2rem); letter-spacing: -0.01em; }
h3 { font-size: 1.15rem; }

p { margin: 0 0 1em; color: rgb(var(--colour-text-secondary)); }

::selection {
    background: rgba(var(--colour-primary), 0.35);
}

:focus-visible {
    outline: 2px solid rgb(var(--colour-primary));
    outline-offset: 2px;
    border-radius: 2px;
}

/* HEADER */

header {
    height: var(--header-height);
    width: 100%;
    position: fixed;
    background: rgba(var(--colour-background), 0.75);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-bottom: 1px solid rgb(var(--colour-border));
    z-index: 10000;
    top: 0;
    left: 0;
}

header > nav {
    max-width: var(--container-width);
    height: 100%;
    margin: 0 auto;
    display: flex;
    align-items: center;
    gap: 4px;
    padding: 0 20px;
}

header a {
    color: rgb(var(--colour-primary));
    text-decoration: none;
    transition: color 120ms ease, background-color 120ms ease;
    padding: 8px 14px;
    border-radius: var(--radius-sm);
    font-weight: 500;
    font-size: 0.95rem;
}
header a:hover {
    color: rgb(var(--colour-primary-hover));
    background-color: rgb(var(--colour-surface-hover));
}
header a[aria-current="page"] {
    color: rgb(var(--colour-primary-hover));
    background-color: rgb(var(--colour-surface-hover));
}

.header-logo {
    height: 70%;
    display: flex;
    align-items: center;
    gap: 8px;
    margin-right: auto;
    padding: 6px 8px;
    font-weight: 700;
    color: rgb(var(--colour-text)) !important;
}
.header-logo:hover { background-color: transparent !important; }
.header-logo > img { height: 100%; border-radius: 6px; }

.nav-links {
    display: flex;
    align-items: center;
    gap: 4px;
}

button.nav-toggle {
    display: none;
    margin-left: auto;
}

@media (max-width: 680px) {
    button.nav-toggle {
        display: inline-flex;
    }
    .nav-links {
        position: fixed;
        top: var(--header-height);
        left: 0;
        right: 0;
        flex-direction: column;
        align-items: stretch;
        gap: 0;
        background: rgb(var(--colour-surface));
        border-bottom: 1px solid rgb(var(--colour-border));
        padding: 8px;
        transform: translateY(-8px);
        opacity: 0;
        pointer-events: none;
        transition: transform 150ms ease, opacity 150ms ease;
    }
    .nav-links[data-open="true"] {
        transform: translateY(0);
        opacity: 1;
        pointer-events: auto;
    }
    header a {
        padding: 12px 14px;
    }
}

/* FOOTER */

footer {
    margin-top: 64px;
    padding: 28px 20px 40px;
    display: flex;
    flex-direction: column;
    gap: 6px;
    align-items: center;
    justify-content: center;
    text-align: center;
    border-top: 1px solid rgb(var(--colour-border));
    color: rgb(var(--colour-text-muted));
    font-size: 0.85rem;
}

/* DEFAULT ELEMENTS */

/* Deliberately not `a:visited`: that pseudo-class outweighs the element selectors in
   `header a` and `.native-source`, repainting them blue once visited. A bare `a` already
   colours visited links — author styles beat the UA sheet whatever the specificity. */
a {
    color: rgb(var(--colour-primary));
}

/* COMMON CLASSES */

.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 20px;
}

.section {
    padding: 56px 0;
}
.section h2 {
    margin-bottom: 12px;
}
.section-intro {
    max-width: 640px;
    margin-bottom: 32px;
}

.card {
    border-radius: var(--radius-md);
    background-color: rgb(var(--colour-surface));
    border: 1px solid rgb(var(--colour-border));
    padding: 20px;
    box-sizing: border-box;
}

.grid {
    display: grid;
    gap: 20px;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 11px 20px;
    border-radius: var(--radius-sm);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.95rem;
    border: 1px solid transparent;
    cursor: pointer;
    transition: background-color 120ms ease, border-color 120ms ease, transform 80ms ease;
}
.button:active {
    transform: translateY(1px);
}
.button-primary, .button-primary:visited {
    background-color: rgb(var(--colour-primary));
    color: rgb(8, 11, 18);
}
.button-primary:hover {
    background-color: rgb(var(--colour-primary-hover));
}
.button-secondary {
    background-color: transparent;
    border-color: rgb(var(--colour-border-strong));
    color: rgb(var(--colour-text));
}
.button-secondary:hover {
    background-color: rgb(var(--colour-surface-hover));
    border-color: rgb(var(--colour-text-secondary));
}
.button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 4px 10px;
    border-radius: 999px;
    font-size: 0.78rem;
    font-weight: 600;
    background-color: rgba(var(--colour-primary), 0.12);
    color: rgb(var(--colour-primary-hover));
    border: 1px solid rgba(var(--colour-primary), 0.3);
}
.badge-accent {
    background-color: rgba(var(--colour-accent), 0.14);
    color: rgb(var(--colour-accent));
    border-color: rgba(var(--colour-accent), 0.35);
}

.button-row {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    margin-top: 12px;
}

.page-header {
    padding-top: 48px;
}

.asset-size {
    font-weight: 400;
    opacity: 0.8;
    font-size: 0.85em;
}

.other-downloads-heading {
    margin-top: 24px;
    margin-bottom: 4px;
    font-size: 1rem;
}

.not-found {
    min-height: calc(80vh - var(--header-height));
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
    gap: 4px;
}
.not-found .badge {
    margin-bottom: 12px;
}
.not-found .button {
    margin-top: 12px;
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
}

/* APP CONTAINER */

#app {
    padding-top: var(--header-height);
    min-height: 100vh;
}