* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: #ffffff;
    min-height: 100vh;
    color: #111;
}

/* 介绍页 */
.container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
}

.intro {
    text-align: center;
    max-width: 500px;
}

.logo {
    width: 120px;
    height: 120px;
    border-radius: 24px;
    margin-bottom: 24px;
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 12px;
    color: #111;
}

.subtitle {
    font-size: 1.1rem;
    color: #666;
    margin-bottom: 16px;
}

.description {
    color: #666;
    line-height: 1.8;
    margin-bottom: 32px;
}

.btn {
    background: #111;
    color: #fff;
    border: none;
    padding: 14px 40px;
    font-size: 1.1rem;
    border-radius: 8px;
    cursor: pointer;
    transition: opacity 0.2s;
}

.btn:hover {
    opacity: 0.8;
}

/* 聊天页 */
.chat-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
    max-width: 800px;
    margin: 0 auto;
    border-left: 1px solid #eee;
    border-right: 1px solid #eee;
}

.chat-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
    border-bottom: 1px solid #eee;
}

.header-info {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 600;
    font-size: 1.1rem;
}

.header-avatar {
    width: 36px;
    height: 36px;
    border-radius: 8px;
}

.back-btn {
    background: transparent;
    color: #111;
    border: 1px solid #ddd;
    padding: 8px 16px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: background 0.2s;
}

.back-btn:hover {
    background: #f5f5f5;
}

.messages {
    flex: 1;
    overflow-y: auto;
    padding: 24px 20px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.message {
    display: flex;
    gap: 12px;
    max-width: 80%;
}

.message.user {
    align-self: flex-end;
    flex-direction: row-reverse;
}

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

.message-avatar {
    width: 32px;
    height: 32px;
    border-radius: 6px;
    flex-shrink: 0;
    margin-top: 2px;
}

.message-content {
    padding: 12px 16px;
    border-radius: 8px;
    line-height: 1.6;
    font-size: 0.95rem;
}

.message.user .message-content {
    background: #111;
    color: #fff;
}

.message.ai .message-content {
    background: #f5f5f5;
    color: #111;
}

.input-area {
    display: flex;
    gap: 12px;
    padding: 16px 20px;
    border-top: 1px solid #eee;
}

#userInput {
    flex: 1;
    background: #f5f5f5;
    border: 1px solid #eee;
    border-radius: 8px;
    padding: 12px 16px;
    color: #111;
    font-size: 0.95rem;
    resize: none;
    outline: none;
    min-height: 48px;
    max-height: 120px;
}

#userInput::placeholder {
    color: #999;
}

#sendBtn {
    background: #111;
    color: #fff;
    border: none;
    padding: 0 24px;
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.95rem;
    transition: opacity 0.2s;
}

#sendBtn:hover {
    opacity: 0.8;
}

#sendBtn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

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

.messages::-webkit-scrollbar-track {
    background: transparent;
}

.messages::-webkit-scrollbar-thumb {
    background: #ddd;
    border-radius: 3px;
}