:root {
    --primary: #ff6b00;
    --border: #e5e7eb;
    --bg: #f4f6fb;
    --dark: #111827;
}
* {
    box-sizing: border-box;
    font-family: "Segoe UI", sans-serif;
}
body {
    margin: 0;
    background: var(--bg);
    color: var(--dark);
}
.topbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 24px;
    background: #fff;
    border-bottom: 1px solid var(--border);
}
.panel {
    max-width: 640px;
    margin: 24px auto;
    background: #fff;
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 16px;
}
.row {
    display: flex;
    gap: 8px;
}
input {
    flex: 1;
    padding: 10px;
    border: 1px solid var(--border);
    border-radius: 8px;
}
.btn {
    background: #fff;
    border: 1px solid var(--border);
    padding: 8px 12px;
    border-radius: 8px;
    cursor: pointer;
}
.btn.primary {
    background: var(--primary);
    color: #fff;
    border-color: var(--primary);
}
.result {
    margin-top: 16px;
}
.card {
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 12px;
}
.section-title {
    margin: 10px 0 6px;
    font-size: 14px;
    font-weight: 700;
    color: var(--dark);
}
.total-line {
    margin-top: 12px;
    font-size: 18px;
    font-weight: 700;
    color: var(--primary);
}
.error {
    color: #b91c1c;
}