:root {
    --bg-color: #f9fafb;
    --chat-bg: #ffffff;
    --text-color: #333333;
    --input-bg: #f1f5f9;
    --border-color: #e2e8f0;
    --user-message-bg: #3b82f6;
    --user-text-color: #ffffff;
    --ai-message-bg: #f1f5f9;
    --ai-text-color: #333333;
    --header-bg: #3b82f6;
    --header-text: #ffffff !important;
    --button-hover: #2563eb;
    --scrollbar-thumb: #cbd5e1;
    --scrollbar-track: #f1f5f9;
}

.dark-mode {
    --bg-color: #1e293b;
    --chat-bg: #0f172a;
    --text-color: #f8fafc;
    --input-bg: #1e293b;
    --border-color: #334155;
    --user-message-bg: #3b82f6;
    --user-text-color: #ffffff;
    --ai-message-bg: #334155;
    --ai-text-color: #f8fafc;
    --header-bg: #0f172a;
    --header-text: #f8fafc !important;
    --button-hover: #60a5fa;
    --scrollbar-thumb: #334155;
    --scrollbar-track: #0f172a;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

.chat-container {
    max-width: 63.5%;
    margin: 20px auto;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    transition: background-color 0.3s ease;
    background-color: var(--chat-bg);
}

.chat-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    background-color: var(--header-bg);
    color: var(--header-text);
}

#theme-toggle {
    background: none;
    border: none;
    color: var(--header-text);
    font-size: 1.2rem;
    cursor: pointer;
    transition: transform 0.2s ease;
}

#theme-toggle:hover {
    transform: scale(1.1);
}

.chat-messages {
    min-height: 400px;
    max-height: 600px;
    overflow-y: auto;
    padding: 20px;
    background-color: var(--chat-bg);
    color: var(--text-color);
}

.chat-messages::-webkit-scrollbar {
    width: 8px;
}

.chat-messages::-webkit-scrollbar-track {
    background: var(--scrollbar-track);
}

.chat-messages::-webkit-scrollbar-thumb {
    background: var(--scrollbar-thumb);
    border-radius: 4px;
}

.message {
    display: flex;
    margin-bottom: 15px;
    animation: fadeIn 0.3s ease;
    width: 100%;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.user-message {
    margin-left: auto;
    flex-direction: row-reverse;
    width: 100%;
}

.ai-message {
    margin-right: auto;
    width: fit-content;
}

.avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 10px;
    flex-shrink: 0;
}

.user-avatar {
    background-color: var(--user-message-bg);
    color: white;
}

.ai-avatar {
    background-color: #94a3b8;
    color: white;
}

.message-content {
    padding: 10px 15px;
    border-radius: 18px;
    line-height: 1.5;
    min-width: 50px;
}

.user-message .message-content {
    background-color: var(--user-message-bg);
    color: var(--user-text-color);
    border-bottom-right-radius: 4px;
}

.ai-message .message-content {
    background-color: var(--ai-message-bg);
    color: var(--ai-text-color);
    border-bottom-left-radius: 4px;
}

.chat-input-area {
    display: flex;
    padding: 15px;
    background-color: var(--chat-bg);
    border-top: 1px solid var(--border-color);
}

.chat-input {
    flex: 1;
    padding: 12px 15px;
    border: 1px solid var(--border-color);
    border-radius: 25px;
    font-size: 14px;
    background-color: var(--input-bg);
    color: var(--text-color);
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.chat-input:focus {
    outline: none;
    border-color: var(--user-message-bg);
    box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
}

.send-button {
    margin-left: 10px;
    padding: 12px 20px;
    background-color: var(--user-message-bg);
    color: white;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    transition: background-color 0.2s ease, transform 0.1s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

.send-button:active {
    transform: scale(0.98);
}

.typing-indicator {
    display: flex;
    align-items: center;
}

.typing-indicator span {
    height: 10px;
    width: 10px;
    margin: 0 2px;
    background-color: #94a3b8;
    border-radius: 50%;
    display: inline-block;
    animation: typing 1.4s infinite ease-in-out both;
}

.typing-indicator span:nth-child(1) {
    animation-delay: -0.32s;
}

.typing-indicator span:nth-child(2) {
    animation-delay: -0.16s;
}

@keyframes typing {
    0% {
        transform: scale(0);
    }
    40% {
        transform: scale(1);
    }
    80% {
        transform: scale(0);
    }
    100% {
        transform: scale(0);
    }
}

.error-message {
    color: #ef4444 !important;
}

/* 响应式设计 */
@media (max-width: 600px) {
    .chat-container {
        margin: 10px;
        height: calc(100vh - 20px);
        display: flex;
        flex-direction: column;
    }

    .chat-messages {
        flex: 1;
        max-height: none;
    }

    .message {
        max-width: 90%;
    }
}