/* Minimal stylesheet. No framework, no script. */

/* Light palette by default; dark follows the OS unless `theme-light` is set,
   and `theme-dark` forces it. */
:root {
    --font: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    --max-width: 800px;

    --color-bg: #ffffff;
    --color-text: #1a1a1a;
    --color-muted: #666666;
    --color-border: #e0e0e0;
    --color-link: #1a56b0;
    --color-link-hover: #0d3e8c;
    --color-primary: #1a56b0;
    --color-primary-hover: #0d3e8c;
    --color-on-primary: #ffffff;
    --color-focus-ring: rgba(26, 86, 176, 0.2);

    --radius: 4px;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
}

@media (prefers-color-scheme: dark) {
    :root:not(.theme-light) {
        --color-bg: #121212;
        --color-text: #e8e8e8;
        --color-muted: #9a9a9a;
        --color-border: #333333;
        --color-link: #7baaf7;
        --color-link-hover: #a8c7fa;
        --color-primary: #7baaf7;
        --color-primary-hover: #a8c7fa;
        --color-on-primary: #121212;
        --color-focus-ring: rgba(123, 170, 247, 0.3);
    }
}

:root.theme-dark {
    --color-bg: #121212;
    --color-text: #e8e8e8;
    --color-muted: #9a9a9a;
    --color-border: #333333;
    --color-link: #7baaf7;
    --color-link-hover: #a8c7fa;
    --color-primary: #7baaf7;
    --color-primary-hover: #a8c7fa;
    --color-on-primary: #121212;
    --color-focus-ring: rgba(123, 170, 247, 0.3);
}

*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
}

body {
    font-family: var(--font);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

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

a:hover {
    color: var(--color-link-hover);
    text-decoration: underline;
}

.skip-link {
    position: absolute;
    top: -100px;
    left: 0;
    background: var(--color-primary);
    color: var(--color-on-primary);
    padding: var(--spacing-sm) var(--spacing-md);
    z-index: 100;
    border-radius: 0 0 var(--radius) 0;
}

.skip-link:focus {
    top: 0;
}

header {
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-sm) var(--spacing-md);
    background-color: var(--color-bg);
}

nav {
    max-width: var(--max-width);
    margin: 0 auto;
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.nav-brand {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-text);
    text-decoration: none;
    letter-spacing: -0.02em;
}

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

.beta-tag {
    margin-left: 0.4em;
    font-size: 0.7rem;
    font-weight: 400;
    letter-spacing: normal;
    color: var(--color-muted);
    vertical-align: super;
}

main {
    flex: 1;
    max-width: var(--max-width);
    width: 100%;
    margin: 0 auto;
    padding: var(--spacing-xl) var(--spacing-md);
}

.about-content h1 {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: var(--spacing-lg);
    letter-spacing: -0.02em;
}

.about-content p {
    margin-bottom: var(--spacing-md);
    line-height: 1.7;
}

.about-content form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    max-width: 400px;
    margin-bottom: var(--spacing-md);
}

label {
    font-weight: 600;
}

input[type="email"] {
    padding: 0.6rem 0.8rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    font-family: var(--font);
    font-size: 1rem;
    color: var(--color-text);
    background-color: var(--color-bg);
    outline: none;
    min-width: 0;
}

input[type="email"]:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 2px var(--color-focus-ring);
}

button {
    align-self: flex-start;
    padding: 0.6rem 1.2rem;
    background-color: var(--color-primary);
    color: var(--color-on-primary);
    border: none;
    border-radius: var(--radius);
    font-family: var(--font);
    font-size: 1rem;
    cursor: pointer;
    white-space: nowrap;
    transition: background-color 0.1s;
}

button:hover {
    background-color: var(--color-primary-hover);
}