:root {
    --primary-color: #6c5ce7;
    --secondary-color: #a29bfe;
    --dark-color: #2d3436;
    --light-color: #f5f6fa;
    --accent-color: #fd79a8;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
}

body {
    background-color: var(--light-color);
    color: var(--dark-color);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

header {
    padding: 30px 0;
    text-align: center;
}

.logo {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 10px;
    letter-spacing: -1px;
}

.tagline {
    font-size: 1.2rem;
    color: var(--dark-color);
    opacity: 0.8;
    margin-bottom: 40px;
}

.main-content {
    text-align: center;
    padding: 20px 0;
}

h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    background: linear-gradient(45deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    line-height: 1.2;
}

.description {
    max-width: 700px;
    margin: 0 auto 40px;
    font-size: 1.1rem;
    color: var(--dark-color);
    opacity: 0.9;
}

.cta-button {
    display: inline-block;
    background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 15px 40px;
    font-size: 1.2rem;
    font-weight: 600;
    border-radius: 50px;
    text-decoration: none;
    border: none;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(108, 92, 231, 0.3);
    margin-bottom: 30px;
}

.cta-button:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(108, 92, 231, 0.4);
}

.cta-button:active {
    transform: translateY(1px);
}

/* 聊天界面样式 */
.chat-container {
    max-width: 800px;
    margin: 0 auto;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 5px 25px rgba(0, 0, 0, 0.1);
    background-color: white;
    flex-direction: column;
    display: flex;
    position: relative;
    min-height: 80px;
    max-height: 95vh;
    transition: all 0.3s ease;
}

.chat-container.expanded {
    height: auto;
    min-height: 200px;
}

.chat-header {
    background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 15px 20px;
    font-size: 1.2rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    user-select: none;
}

.chat-header .expand-icon {
    transition: transform 0.3s ease;
}

.chat-container.expanded .chat-header .expand-icon {
    transform: rotate(180deg);
}

.chat-messages {
    flex: 1;
    padding: 20px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 15px;
    align-items: flex-start;
    position: relative;
    max-height: calc(95vh - 130px);
}

.message {
    max-width: 80%;
    padding: 12px 16px;
    border-radius: 18px;
    line-height: 1.4;
    word-wrap: break-word;
    text-align: left;
    opacity: 0;
    transform: translateY(10px);
    animation: fadeInUp 0.3s ease forwards;
    position: relative;
}

@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.message:hover .message-actions {
    opacity: 1;
}

.message-actions {
    position: absolute;
    top: -20px;
    right: 0;
    display: flex;
    gap: 8px;
    opacity: 0;
    transition: opacity 0.2s ease;
    background-color: rgba(255, 255, 255, 0.9);
    padding: 2px 6px;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.message-action-btn {
    cursor: pointer;
    padding: 2px 6px;
    font-size: 0.9rem;
    color: var(--dark-color);
    opacity: 0.7;
    transition: all 0.2s ease;
    border: none;
    background: none;
    border-radius: 4px;
}

.message-action-btn:hover {
    opacity: 1;
    background-color: rgba(0, 0, 0, 0.05);
}

.message-action-btn.edit-btn:hover {
    color: var(--primary-color);
}

.message-action-btn.delete-btn:hover {
    color: #e74c3c;
}

.message-action-btn.resend-btn:hover {
    color: #2ecc71;
}

.message.editing {
    background-color: rgba(108, 92, 231, 0.1);
}

.message.editing .message-content {
    display: none;
}

.message-edit-input {
    width: 100%;
    padding: 8px 12px;
    border: 1px solid var(--primary-color);
    border-radius: 12px;
    font-size: 1rem;
    line-height: 1.4;
    resize: vertical;
    min-height: 60px;
    margin-bottom: 8px;
}

.message-edit-actions {
    display: flex;
    gap: 8px;
    justify-content: flex-end;
}

.message-edit-btn {
    padding: 4px 12px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.2s ease;
}

.message-edit-btn.save {
    background-color: var(--primary-color);
    color: white;
}

.message-edit-btn.cancel {
    background-color: #e0e0e0;
    color: var(--dark-color);
}

.message-edit-btn:hover {
    opacity: 0.9;
}

.user-message {
    align-self: flex-end;
    background-color: var(--primary-color);
    color: white;
    border-bottom-right-radius: 5px;
    animation-delay: 0.1s;
}

.bot-message {
    align-self: flex-start;
    background-color: #f0f0f0;
    color: var(--dark-color);
    border-bottom-left-radius: 5px;
}

.chat-input-container {
    display: flex;
    padding: 15px;
    background-color: #f8f8f8;
    border-top: 1px solid #eee;
    opacity: 0;
    height: 0;
    overflow: hidden;
    transition: all 0.3s ease;
    position: relative;
}

.chat-container.expanded .chat-input-container {
    opacity: 1;
    height: auto;
    min-height: 60px;
}

.resize-handle,
.resize-handle:hover,
.resize-handle::after {
    display: none;
}

.chat-input {
    flex: 1;
    padding: 12px 15px;
    border: 1px solid #ddd;
    border-radius: 25px;
    font-size: 1rem;
    outline: none;
    transition: border 0.3s;
}

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

.send-button {
    margin-left: 10px;
    padding: 12px 20px;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    font-weight: 600;
    transition: background-color 0.3s;
}

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

.typing-indicator {
    display: none;
    align-self: flex-start;
    padding: 10px 15px;
    background-color: #f0f0f0;
    border-radius: 18px;
    color: var(--dark-color);
    font-style: italic;
    margin-bottom: 15px;
    animation: pulse 1.5s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 0.6; }
    50% { opacity: 1; }
}

.initial-message {
    padding: 15px;
    text-align: center;
    color: var(--dark-color);
    opacity: 0.7;
}

footer {
    text-align: center;
    padding: 30px 0;
    color: var(--dark-color);
    opacity: 0.7;
    font-size: 0.9rem;
    margin-top: auto;
}

.header-buttons {
    display: flex;
    gap: 15px;
    align-items: center;
}

.maximize-icon {
    cursor: pointer;
    font-size: 1.1rem;
    opacity: 0.8;
    transition: all 0.3s ease;
    padding: 2px 5px;
    border-radius: 4px;
}

.maximize-icon:hover {
    opacity: 1;
    background-color: rgba(255, 255, 255, 0.1);
}

.chat-container.maximized {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 1000;
    border-radius: 0;
    margin: 0;
    max-width: 100%;
    height: 100vh;
    max-height: 100vh;
}

.chat-container.maximized .chat-messages {
    max-height: calc(100vh - 130px);
}

.chat-container.maximized .chat-input-container {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background-color: #f8f8f8;
    border-top: 1px solid #eee;
}

@media (max-width: 768px) {
    h1 {
        font-size: 2.2rem;
    }
    
    .description {
        font-size: 1rem;
        padding: 0 20px;
    }
    
    .logo {
        font-size: 2rem;
    }
    
    .tagline {
        font-size: 1rem;
    }
    
    .chat-container.expanded {
        min-height: 180px;
    }
    
    .chat-messages {
        max-height: calc(95vh - 120px);
    }
    
    .chat-container.maximized .chat-messages {
        max-height: calc(100vh - 120px);
    }
    
    .header-buttons {
        gap: 10px;
    }
    
    .maximize-icon {
        font-size: 1rem;
    }
}