body {
    font-family: Arial, sans-serif;
    margin: 0;
    background: #f4f7fb;
    color: #202124;
}

.container {
    max-width: 960px;
    margin: 0 auto;
    padding: 24px;
}

h1 {
    margin-bottom: 16px;
}

.layout {
    display: grid;
    grid-template-columns: 220px 1fr;
    gap: 24px;
}

.sidebar {
    background: #fff;
    border: 1px solid #dfe1e5;
    border-radius: 12px;
    padding: 20px;
}

.sidebar button,
.sidebar a {
    display: block;
    width: 100%;
    margin-bottom: 10px;
    padding: 12px 14px;
    border: none;
    background: #1a73e8;
    color: #fff;
    border-radius: 8px;
    cursor: pointer;
    text-align: left;
    text-decoration: none;
}

.sidebar button:hover,
.sidebar a:hover {
    background: #1669c1;
}

.sidebar button.active {
    background: #800020;
    box-shadow: 0 4px 10px rgba(128, 0, 32, .25);
}

.content {
    background: #fff;
    border: 1px solid #dfe1e5;
    border-radius: 12px;
    padding: 24px;
}

.content section {
    display: none;
}

.content section.active {
    display: block;
}

.field {
    margin-bottom: 16px;
}

.field label {
    display: block;
    margin-bottom: 6px;
    font-weight: 600;
}

.field input,
.field select {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid #c6c6c6;
    border-radius: 8px;
}

.inline-field {
    display: flex;
    gap: 10px;
    align-items: center;
}

.button-primary {
    background: #1a73e8;
    color: #fff;
    border: none;
    padding: 12px 16px;
    border-radius: 8px;
    cursor: pointer;
}

.button-primary:hover {
    background: #1669c1;
}

.button-secondary {
    background: #f1f3f4;
    color: #202124;
    border: 1px solid #c6c6c6;
    padding: 10px 14px;
    border-radius: 8px;
    cursor: pointer;
    margin-left: 12px;
}

.button-secondary:hover {
    background: #e8eaed;
}

.result {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: #e8f0fe;
    border: 1px solid #d2e3fc;
    padding: 18px;
    border-radius: 10px;
    margin-top: 18px;
    font-family: monospace;
    font-size: 1.2rem;
}

.notice {
    background: #f1f3f4;
    padding: 12px 14px;
    border-radius: 10px;
    margin-bottom: 16px;
}

.page-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: #fff;
    border-top: 1px solid #dfe1e5;
    margin-top: 24px;
    padding: 12px 20px;
    border-radius: 0 0 12px 12px;
}

.footer-left {
    font-size: 8px;
    color: #5f6368;
}

.footer-right {
    font-size: 12px;
    color: #5f6368;
}

@media (max-width: 760px) {
    .layout {
        grid-template-columns: 1fr;
    }
}