/* 全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Microsoft YaHei', '微软雅黑', Arial, sans-serif;
}

:root {
    /* 定义颜色变量 */
    --primary-color: #4a6fa5;
    --secondary-color: #6b8cae;
    --background-color: #f5f7fa;
    --text-color: #333;
    --light-text: #666;
    --border-color: #ddd;
    --user-message-bg: #e1f5fe;
    --ai-message-bg: #f0f4f8;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

body {
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
}

/* 容器样式 */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 页眉样式 */
header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 20px 0;
    box-shadow: var(--shadow);
}

header h1 {
    font-size: 2rem;
    margin-bottom: 5px;
    display: flex;
    align-items: center;
    gap: 10px;
}

header p {
    font-size: 1rem;
    opacity: 0.9;
}

/* 主要内容区域样式 */
main {
    padding: 30px 0;
    min-height: calc(100vh - 180px); /* 确保页面至少填满视口高度 */
}

/* 聊天容器样式 */
.chat-container {
    background-color: white;
    border-radius: 10px;
    box-shadow: var(--shadow);
    overflow: hidden;
    display: flex;
    flex-direction: column;
    height: 70vh; /* 设置聊天区域高度 */
    max-height: 800px;
}

/* 聊天历史区域样式 */
.chat-history {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
}

/* 消息样式 */
.message {
    margin-bottom: 15px;
    display: flex;
    flex-direction: column;
}

.user-message {
    align-items: flex-end;
}

.ai-message {
    align-items: flex-start;
}

.message-content {
    max-width: 80%;
    padding: 12px 15px;
    border-radius: 18px;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
    position: relative;
}

.user-message .message-content {
    background-color: var(--user-message-bg);
    border-bottom-right-radius: 5px;
}

.ai-message .message-content {
    background-color: var(--ai-message-bg);
    border-bottom-left-radius: 5px;
}

.message-content p {
    margin-bottom: 5px;
}

.message-content p:last-child {
    margin-bottom: 0;
}

/* 消息输入区域样式 */
.message-input {
    display: flex;
    padding: 15px;
    border-top: 1px solid var(--border-color);
    background-color: white;
}

.message-input textarea {
    flex: 1;
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 10px 15px;
    resize: none;
    outline: none;
    transition: border-color 0.3s;
    font-size: 1rem;
}

.message-input textarea:focus {
    border-color: var(--primary-color);
}

.send-button {
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    margin-left: 10px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color 0.3s;
}

.send-button:hover {
    background-color: var(--secondary-color);
}

/* 页脚样式 */
footer {
    background-color: #333;
    color: white;
    padding: 20px 0;
    text-align: center;
}

/* 响应式设计 */
@media (max-width: 768px) {
    header h1 {
        font-size: 1.5rem;
    }
    
    .message-content {
        max-width: 90%;
    }
    
    .chat-container {
        height: 80vh;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 1.2rem;
    }
    
    .container {
        padding: 0 10px;
    }
    
    .message-content {
        max-width: 95%;
    }
}

/* 动画效果 */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.message {
    animation: fadeIn 0.3s ease-out;
}

/* 滚动条样式 */
.chat-history::-webkit-scrollbar {
    width: 6px;
}

.chat-history::-webkit-scrollbar-track {
    background: #f1f1f1;
}

.chat-history::-webkit-scrollbar-thumb {
    background: #ccc;
    border-radius: 3px;
}

.chat-history::-webkit-scrollbar-thumb:hover {
    background: #aaa;
}