/* === TOKENS === */

:root {
    --bg: #fafaf8;
    --fg: #1a1a18;
    --muted: #8a8a82;
    --border: #e4e4de;
    --accent: #1a1a18;
    --accent-bg: #f0f0ec;
    --success: #3a7d44;
    --success-bg: #e8f0e8;
    --warning: #b8860b;
    --warning-bg: #fdf6e3;

    --font-medium: 500;
    --font-bold: 700;
    --leading: 1.4;
    --leading-slim: 1.2;
    --leading-fine: 1.1;
    --heading-kerning: -0.015em;
    --font-base: -apple-system, system-ui, sans-serif;
    --font-serif: Georgia, sans-serif;
    --space-s: clamp(0.75rem, 0.6829rem + 0.3356vi, 1rem);
    --space-m: clamp(1.125rem, 1.0243rem + 0.5034vi, 1.5rem);
    --space-l: clamp(1.5rem, 1.3658rem + 0.6711vi, 2rem);
    --space-s-m: clamp(0.75rem, 0.5487rem + 1.0067vi, 1.5rem);
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #1a1a18;
        --fg: #e8e8e2;
        --muted: #7a7a72;
        --border: #2e2e2a;
        --accent: #e8e8e2;
        --accent-bg: #2a2a26;
        --success: #5a9d64;
        --success-bg: #1e2e1e;
        --warning: #d4a843;
        --warning-bg: #2e2a1e;
    }
}

/* === BASE === */

*, :after, :before {
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

html {
    -moz-text-size-adjust: none;
    -webkit-text-size-adjust: none;
    text-size-adjust: none;
}

body {
    background: var(--bg);
    color: var(--fg);
    font-family: var(--font-base);
    font-size: 14px;
    line-height: var(--leading);
    margin: 0 auto;
    max-width: 420px;
    min-height: 100dvh;
    overflow-x: hidden;
    padding: 0 1.25rem;
    padding-top: env(safe-area-inset-top, 0);
}

body, h1, h2, h3, h4, p {
    margin-block-end: 0;
}

h1, h2, h3, h4 {
    font-family: var(--font-base);
    font-weight: var(--font-bold);
    letter-spacing: var(--heading-kerning);
    line-height: var(--leading-fine);
    text-wrap: balance;
}

button, h1, h2, h3, h4, input, label {
    line-height: 1.1;
}

button, input, select, textarea {
    font: inherit;
}

strong {
    font-family: var(--font-serif);
    font-weight: 700;
}

a {
    color: currentcolor;
}

a:hover {
    text-decoration: none;
}

[hidden] {
    display: none !important;
}

/* === LAYOUT === */

.stack {
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
}

.stack > * {
    margin-block: 0;
}

.stack > * + * {
    margin-block-start: var(--space, var(--space-m));
}

.stack-s { --space: var(--space-s); }
.stack-l { --space: var(--space-l); }

.center {
    box-sizing: content-box;
    margin-inline: auto;
    max-inline-size: 420px;
}

.box {
    padding: 0;
}

.region {
    padding-block: var(--space-s);
}

/* === FORMS === */

form {
    display: flex;
    flex-direction: column;
    gap: var(--space-s);
}

form > * {
    text-align: left;
}

label {
    font-size: 14px;
    font-weight: 450;
}

input:not([type="date"]),
select {
    appearance: none;
    -webkit-appearance: none;
}

input,
select {
    border: 1.5px solid var(--border);
    border-radius: 8px;
    padding: 10px 12px;
    font-size: 16px;
    background: var(--bg);
    color: var(--fg);
    width: 100%;
}

input[type="date"] {
    min-width: 0;
    max-width: 100%;
}

select {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8'%3E%3Cpath d='M1 1l5 5 5-5' fill='none' stroke='%238a8a82' stroke-width='1.5' stroke-linecap='round'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    padding-right: 32px;
}

input[type="number"]::-webkit-inner-spin-button,
input[type="number"]::-webkit-outer-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

input[type="number"] {
    -moz-appearance: textfield;
}

input:focus,
select:focus {
    border-color: var(--accent);
    outline: none;
}

small {
    font-size: 12px;
    color: var(--muted);
}

/* === BUTTONS === */

.button {
    align-items: center;
    background: var(--fg);
    border: none;
    border-radius: 10px;
    color: var(--bg);
    cursor: pointer;
    display: block;
    font-family: var(--font-base);
    font-size: 16px;
    font-weight: var(--font-medium);
    justify-content: center;
    line-height: var(--leading-slim);
    padding: 14px;
    text-decoration: none;
    transition: opacity 0.15s;
    width: 100%;
}

.button:active { opacity: 0.8; }
.button:disabled { opacity: 0.4; cursor: default; }

.button[data-button-variant=primary] {
    background: var(--fg);
    color: var(--bg);
}

.button[data-button-variant=primary]:hover:not([aria-selected=true]) {
    opacity: 0.8;
}

/* === RESULTS === */

.result-card {
    border: 1px solid var(--border);
    border-radius: 10px;
    overflow: hidden;
}

.result-header {
    padding: 10px 16px;
    font-size: 13px;
    font-weight: 500;
    border-bottom: 1px solid var(--border);
}

.result-header[data-variant=success] {
    background: var(--success-bg);
    color: var(--success);
}

.result-header[data-variant=warning] {
    background: var(--warning-bg);
    color: var(--warning);
}

.result-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 16px;
    border-bottom: 1px solid var(--border);
}

.result-row:last-child {
    border-bottom: none;
}

.result-label {
    font-size: 14px;
    color: var(--muted);
}

.result-value {
    font-size: 14px;
    font-weight: 500;
}

/* === HEADER === */

.hero-header {
    padding: 2rem 0 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: baseline;
}

.hero-header h1 {
    font-size: 15px;
    font-weight: var(--font-medium);
    letter-spacing: -0.01em;
}

.hero-header nav a {
    font-size: 13px;
    color: var(--muted);
    text-decoration: none;
}

.hero-header nav a:active { opacity: 0.5; }