:root {
    --bg: #0f1220;
    --panel: #171a2b;
    --panel-2: #1f2438;
    --text: #eef2ff;
    --muted: #b8c0e0;
    --accent: #7aa2ff;
    --ok: #67e8a5;
    --error: #ff8b8b;
    --border: #2e3552;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family:
        system-ui,
        -apple-system,
        Segoe UI,
        Roboto,
        Helvetica,
        Arial,
        sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
}

.wrap {
    max-width: 1000px;
    margin: 0 auto;
    padding: 28px 16px 48px;
}

h1 {
    margin: 0 0 8px;
    font-size: 1.7rem;
    letter-spacing: 0.2px;
}

.subtitle {
    margin: 0 0 24px;
    color: var(--muted);
    font-size: 0.98rem;
    line-height: 1.45;
}

.grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

@media (max-width: 900px) {
    .grid {
        grid-template-columns: 1fr;
    }
}

.card {
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 16px;
}

.card h2 {
    margin: 0 0 14px;
    font-size: 1.05rem;
    color: #dbe4ff;
}

.field {
    margin-bottom: 12px;
}

label {
    display: block;
    margin-bottom: 6px;
    font-size: 0.9rem;
    color: var(--muted);
}

input {
    width: 100%;
    border: 1px solid var(--border);
    background: #0f1324;
    color: var(--text);
    border-radius: 10px;
    padding: 10px 12px;
    font-size: 0.98rem;
    outline: none;
}

input:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(122, 162, 255, 0.18);
}

.hint {
    font-size: 0.82rem;
    color: var(--muted);
    margin-top: 4px;
}

.actions {
    margin-top: 6px;
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

button {
    border: 1px solid var(--border);
    background: #243051;
    color: var(--text);
    border-radius: 10px;
    padding: 10px 14px;
    cursor: pointer;
    font-weight: 600;
}

button:hover {
    filter: brightness(1.08);
}

button:active {
    transform: translateY(1px);
}

.result {
    margin-top: 18px;
    background: #10182e;
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 14px;
    line-height: 1.45;
}

.ok {
    color: var(--ok);
    font-weight: 700;
}

.error {
    color: var(--error);
    font-weight: 700;
}

.mono {
    font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    background: rgba(255, 255, 255, 0.06);
    padding: 2px 6px;
    border-radius: 6px;
}

.formula {
    margin-top: 16px;
    color: var(--muted);
    font-size: 0.88rem;
    line-height: 1.5;
}

.formula code {
    color: #d6e2ff;
}

.small {
    font-size: 0.86rem;
    color: var(--muted);
    margin-top: 10px;
}