body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    background-image: radial-gradient(circle, rgba(255,255,255,0.1) 1px, transparent 1px);
    background-size: 20px 20px;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    overflow: hidden;
    animation: backgroundShift 10s ease-in-out infinite;
}

@keyframes backgroundShift {
    0%, 100% { background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); }
    50% { background: linear-gradient(135deg, #764ba2 0%, #667eea 100%); }
}

.particles {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
}

.particle {
    position: absolute;
    width: 10px;
    height: 10px;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    animation: float 6s ease-in-out infinite;
}

.particle:nth-child(1) { left: 10%; animation-delay: 0s; }
.particle:nth-child(2) { left: 20%; animation-delay: 1s; }
.particle:nth-child(3) { left: 30%; animation-delay: 2s; }
.particle:nth-child(4) { left: 40%; animation-delay: 3s; }
.particle:nth-child(5) { left: 50%; animation-delay: 4s; }
.particle:nth-child(6) { left: 60%; animation-delay: 5s; }
.particle:nth-child(7) { left: 70%; animation-delay: 1s; }
.particle:nth-child(8) { left: 80%; animation-delay: 2s; }
.particle:nth-child(9) { left: 90%; animation-delay: 3s; }
.particle:nth-child(10) { left: 95%; animation-delay: 4s; }

@keyframes float {
    0%, 100% { transform: translateY(100vh) rotate(0deg); opacity: 0; }
    50% { opacity: 1; }
}

.chat-container {
    width: 450px;
    height: 650px;
    background-color: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.1);
    display: flex;
    flex-direction: column;
    backdrop-filter: blur(10px);
}

.chat-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
    border-bottom: 1px solid rgba(0,0,0,0.1);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 20px 20px 0 0;
}

.chat-header h1 {
    margin: 0;
    font-size: 1.5em;
    font-weight: 600;
}

.header-buttons {
    display: flex;
    gap: 10px;
}

#dark-mode-button, #clear-button {
    background: none;
    border: none;
    color: white;
    font-size: 1.2em;
    cursor: pointer;
    transition: transform 0.2s;
}

#dark-mode-button:hover, #clear-button:hover {
    transform: scale(1.1);
}

.chat-messages {
    flex: 1;
    padding: 20px;
    overflow-y: auto;
    scroll-behavior: smooth;
}

.message-container {
    display: flex;
    align-items: flex-end;
    margin-bottom: 15px;
    animation: slideIn 0.5s ease-out;
}

.user-container {
    justify-content: flex-end;
}

.bot-container {
    justify-content: flex-start;
}

.avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    margin: 0 10px;
    background: rgba(255,255,255,0.2);
    border: 2px solid rgba(255,255,255,0.3);
}

.message {
    padding: 12px 16px;
    border-radius: 18px;
    max-width: 70%;
    word-wrap: break-word;
    position: relative;
}

.timestamp {
    font-size: 10px;
    color: rgba(255,255,255,0.7);
    margin: 0 10px;
    align-self: flex-end;
}

@keyframes slideIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.user-message {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    align-self: flex-end;
    margin-left: auto;
    box-shadow: 0 4px 8px rgba(102, 126, 234, 0.3);
}

.bot-message {
    background-color: #f8f9fa;
    color: #333;
    border: 1px solid #e9ecef;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.typing-indicator {
    display: flex;
    justify-content: flex-start;
    padding: 20px;
}

.typing-indicator span {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background-color: #667eea;
    margin: 0 2px;
    animation: typing 1.4s infinite ease-in-out;
}

.typing-indicator span:nth-child(1) { animation-delay: -0.32s; }
.typing-indicator span:nth-child(2) { animation-delay: -0.16s; }

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

.input-container {
    display: flex;
    padding: 20px;
    border-top: 1px solid rgba(0,0,0,0.1);
}

#user-input {
    flex: 1;
    padding: 12px 16px;
    border: 2px solid #e9ecef;
    border-radius: 25px;
    outline: none;
    transition: border-color 0.3s;
}

#user-input:focus {
    border-color: #667eea;
}

#send-button {
    padding: 12px 20px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 25px;
    margin-left: 10px;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    font-size: 16px;
}

#send-button:hover {
    transform: scale(1.05);
    box-shadow: 0 4px 8px rgba(102, 126, 234, 0.3);
}

#send-button:active {
    transform: scale(0.95);
}

/* Dark Mode */
body.dark-mode {
    background: linear-gradient(135deg, #2c3e50 0%, #34495e 100%);
    background-image: radial-gradient(circle, rgba(255,255,255,0.05) 1px, transparent 1px);
    background-size: 20px 20px;
    animation: backgroundShiftDark 10s ease-in-out infinite;
}

@keyframes backgroundShiftDark {
    0%, 100% { background: linear-gradient(135deg, #2c3e50 0%, #34495e 100%); }
    50% { background: linear-gradient(135deg, #34495e 0%, #2c3e50 100%); }
}

body.dark-mode .particle {
    background: rgba(255, 255, 255, 0.1);
}

body.dark-mode .chat-container {
    background-color: rgba(44, 62, 80, 0.95);
    color: #ecf0f1;
}

body.dark-mode .chat-header {
    background: linear-gradient(135deg, #34495e 0%, #2c3e50 100%);
    border-bottom-color: rgba(255,255,255,0.1);
}

body.dark-mode .bot-message {
    background-color: #34495e;
    color: #ecf0f1;
    border-color: #7f8c8d;
}

body.dark-mode .input-container {
    border-top-color: rgba(255,255,255,0.1);
}

body.dark-mode #user-input {
    background-color: #34495e;
    border-color: #7f8c8d;
    color: #ecf0f1;
}

body.dark-mode #user-input:focus {
    border-color: #3498db;
}

.scroll-to-bottom {
    position: absolute;
    bottom: 20px;
    right: 20px;
    background: rgba(102, 126, 234, 0.8);
    color: white;
    border: none;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    transition: background 0.3s;
}

.scroll-to-bottom:hover {
    background: rgba(102, 126, 234, 1);
}

.bubble {
    position: absolute;
    bottom: -10px;
    width: 20px;
    height: 20px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    animation: bubbleFloat 15s linear infinite;
}

@keyframes bubbleFloat {
    0% { transform: translateY(0) scale(1); opacity: 0.5; }
    50% { opacity: 0.8; }
    100% { transform: translateY(-100vh) scale(0.5); opacity: 0; }
}

body.dark-mode .bubble {
    background: rgba(255, 255, 255, 0.1);
}

/* Neural Network AI Animation */
.node {
    position: absolute;
    width: 8px;
    height: 8px;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.8) 0%, rgba(102, 126, 234, 0.6) 70%);
    border-radius: 50%;
    animation: pulse 2s ease-in-out infinite;
    box-shadow: 0 0 10px rgba(102, 126, 234, 0.5);
    z-index: 1;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); opacity: 0.7; }
    50% { transform: scale(1.2); opacity: 1; box-shadow: 0 0 20px rgba(102, 126, 234, 0.8); }
}

.connection {
    position: absolute;
    height: 2px;
    background: linear-gradient(to right, rgba(102, 126, 234, 0.3), rgba(102, 126, 234, 0.6));
    transform-origin: left center;
    animation: connectionGlow 3s ease-in-out infinite;
    z-index: 0;
}

@keyframes connectionGlow {
    0%, 100% { opacity: 0.3; }
    50% { opacity: 0.7; box-shadow: 0 0 5px rgba(102, 126, 234, 0.4); }
}

body.dark-mode .node {
    background: radial-gradient(circle, rgba(255, 255, 255, 0.6) 0%, rgba(52, 73, 94, 0.8) 70%);
    box-shadow: 0 0 10px rgba(52, 73, 94, 0.5);
}

body.dark-mode .connection {
    background: linear-gradient(to right, rgba(52, 73, 94, 0.3), rgba(52, 73, 94, 0.6));
}