body {
    margin: 0;
    font-family: Arial, "Microsoft YaHei", sans-serif;
    background: #f5f5f5;
    color: #222;
}

.container {
    max-width: 860px;
    margin: 0 auto;
    padding: 40px 20px;
}

.hero {
    margin-bottom: 32px;
}

.hero h1 {
    font-size: 42px;
    margin-bottom: 12px;
}

.hero p {
    font-size: 18px;
    color: #666;
}

.card {
    background: white;
    padding: 24px;
    margin-bottom: 20px;
    border-radius: 12px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
}

.card h2 {
    margin-top: 0;
}

a {
    color: #2563eb;
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

.hidden {
    display: none;
}

.text-input {
    width: 100%;
    box-sizing: border-box;
    padding: 12px 14px;
    margin: 12px 0;
    border: 1px solid #ddd;
    border-radius: 8px;
    font-size: 16px;
}

.message-editor {
    width: 100%;
    min-height: 260px;
    box-sizing: border-box;
    padding: 14px;
    margin: 12px 0;
    border: 1px solid #ddd;
    border-radius: 8px;
    font-size: 16px;
    line-height: 1.6;
    resize: vertical;
}

.button-row {
    display: flex;
    gap: 12px;
}

.button {
    padding: 10px 18px;
    border: none;
    border-radius: 8px;
    background: #2563eb;
    color: white;
    font-size: 15px;
    cursor: pointer;
}

.button:hover {
    background: #1d4ed8;
}

.button.secondary {
    background: #6b7280;
}

.button.secondary:hover {
    background: #4b5563;
}

.message-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.message-item {
    padding: 16px;
    border-radius: 10px;
    background: #f9fafb;
    border: 1px solid #e5e7eb;
}

.message-time {
    margin: 0 0 8px 0;
    color: #6b7280;
    font-size: 14px;
}

.message-content {
    margin: 0;
    white-space: pre-wrap;
    line-height: 1.7;
}