body {
    margin: 0;
    font-family: Arial, "Microsoft YaHei", sans-serif;
    background: #f4f6fb;
    color: #1f2937;
}

.container {
    max-width: 960px;
    margin: 0 auto;
    padding: 34px 18px;
}

.top-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
    margin-bottom: 18px;
    flex-wrap: wrap;
}

.back-link {
    text-decoration: none;
    background: #6b7280;
    color: white;
    padding: 10px 14px;
    border-radius: 12px;
    font-weight: bold;
}

.grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 18px;
}

.card {
    background: white;
    border-radius: 18px;
    padding: 22px;
    box-shadow: 0 4px 14px rgba(0, 0, 0, 0.08);
}

h1, h2 {
    margin-top: 0;
}

p {
    line-height: 1.8;
    color: #374151;
}

input {
    width: 100%;
    padding: 11px 12px;
    border-radius: 12px;
    border: 1px solid #d1d5db;
    margin-bottom: 12px;
    box-sizing: border-box;
    font-size: 15px;
}

button {
    border: none;
    border-radius: 12px;
    padding: 11px 16px;
    font-size: 15px;
    font-weight: bold;
    cursor: pointer;
    background: #2563eb;
    color: white;
}

.message {
    margin-top: 14px;
    min-height: 22px;
    padding: 12px 14px;
    border-radius: 12px;
    border: 1px solid transparent;
    background: #f8fafc;
    color: #374151;
    line-height: 1.7;
    white-space: pre-line;
}

.message:empty {
    display: none;
}

.message.info {
    background: #eff6ff;
    color: #1d4ed8;
    border-color: #bfdbfe;
}

.message.success {
    background: #ecfdf5;
    color: #166534;
    border-color: #86efac;
}

.message.waiting {
    background: #fffbeb;
    color: #92400e;
    border-color: #fcd34d;
}

.message.error {
    background: #fef2f2;
    color: #991b1b;
    border-color: #fca5a5;
}

.error-box {
    background: #fee2e2;
    color: #991b1b;
    padding: 12px 14px;
    border-radius: 12px;
    margin-bottom: 14px;
}

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