:root {
    --bg: #f7f8fa;
    --panel: #ffffff;
    --text: #1f2430;
    --muted: #5b6472;
    --border: #e1e4e9;
    --accent: #1f6feb;
    --accent-dark: #1a5fc9;
    --error: #b3261e;
    --error-bg: #fdecea;
    --radius: 10px;
}

* { box-sizing: border-box; }

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
}

.wrap {
    max-width: 860px;
    margin: 0 auto;
    padding: 0 20px;
}

.site-header {
    background: var(--panel);
    border-bottom: 1px solid var(--border);
}

.site-header .wrap {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    padding-top: 14px;
    padding-bottom: 14px;
    gap: 10px;
}

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

.site-nav a {
    color: var(--muted);
    text-decoration: none;
    margin-left: 18px;
    font-size: 0.95rem;
}

.site-nav a:first-child { margin-left: 0; }

.site-nav a:hover { color: var(--accent); }

.content {
    padding: 36px 20px 60px;
}

h1 { font-size: 1.9rem; margin-bottom: 6px; }
h2 { font-size: 1.3rem; margin-top: 2em; }

.lead {
    color: var(--muted);
    margin-top: 0;
}

.card {
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    margin: 24px 0;
}

label {
    display: block;
    font-weight: 600;
    font-size: 0.9rem;
    margin-bottom: 6px;
}

input[type="text"], select {
    width: 100%;
    padding: 10px 12px;
    font-size: 1rem;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: #fff;
    color: var(--text);
    margin-bottom: 16px;
}

input[type="text"]:focus, select:focus {
    outline: 2px solid var(--accent);
    outline-offset: 1px;
}

.grid-3 {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 14px;
}

@media (max-width: 640px) {
    .grid-3 { grid-template-columns: 1fr; }
}

.btn {
    background: var(--accent);
    color: #fff;
    border: none;
    padding: 11px 22px;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
}

.btn:hover { background: var(--accent-dark); }

.result {
    margin-top: 18px;
    padding: 14px 16px;
    background: #eef5ff;
    border-radius: 8px;
    display: flex;
    justify-content: space-between;
    align-items: baseline;
}

.result-label {
    font-size: 0.85rem;
    color: var(--muted);
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.result-value {
    font-size: 1.4rem;
    font-weight: 700;
}

.error {
    margin-top: 14px;
    padding: 12px 14px;
    background: var(--error-bg);
    color: var(--error);
    border-radius: 8px;
    font-size: 0.95rem;
}

.quick-buttons { margin: 20px 0 36px; }

.chip-row {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.chip {
    border: 1px solid var(--border);
    background: #fff;
    border-radius: 6px;
    padding: 8px 14px;
    font-size: 1rem;
    cursor: pointer;
}

.chip:hover { border-color: var(--accent); color: var(--accent); }

.info-block {
    border-top: 1px solid var(--border);
    padding-top: 8px;
}

code {
    background: #f0f1f4;
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.9em;
}

.site-footer {
    border-top: 1px solid var(--border);
    background: var(--panel);
    color: var(--muted);
    font-size: 0.85rem;
}

.site-footer .wrap {
    padding: 20px;
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 8px;
}

.site-footer a { color: var(--muted); }