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

:root {
    --bg-gradient-start: #667eea;
    --bg-gradient-end: #764ba2;
    --header-bg: rgba(255, 255, 255, 0.95);
    --text-primary: #333;
    --text-secondary: #666;
    --message-user-bg: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --message-bot-bg: white;
    --message-bot-border: #e0e0e0;
    --input-bg: white;
    --input-border: #e0e0e0;
    --input-focus-border: #667eea;
    --status-bg: rgba(255, 255, 255, 0.9);
    --status-border: rgba(0, 0, 0, 0.1);
    --scrollbar-track: rgba(255, 255, 255, 0.1);
    --scrollbar-thumb: rgba(255, 255, 255, 0.3);
    --empty-state-text: rgba(255, 255, 255, 0.9);
}

body.dark-mode {
    --bg-gradient-start: #1a1a2e;
    --bg-gradient-end: #16213e;
    --header-bg: rgba(26, 26, 46, 0.95);
    --text-primary: #e0e0e0;
    --text-secondary: #b0b0b0;
    --message-user-bg: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --message-bot-bg: #2a2a3e;
    --message-bot-border: #3a3a4e;
    --input-bg: #2a2a3e;
    --input-border: #3a3a4e;
    --input-focus-border: #667eea;
    --status-bg: rgba(26, 26, 46, 0.9);
    --status-border: rgba(255, 255, 255, 0.1);
    --scrollbar-track: rgba(0, 0, 0, 0.3);
    --scrollbar-thumb: rgba(255, 255, 255, 0.2);
    --empty-state-text: rgba(224, 224, 224, 0.9);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    color: var(--text-primary);
    transition: background 0.3s ease;
}

.header {
    background: var(--header-bg);
    backdrop-filter: blur(10px);
    padding: 1rem 1.5rem;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
    transition: background 0.3s ease;
}

.header h1 {
    font-size: 1.5rem;
    color: #667eea;
    font-weight: 600;
}

.header-controls {
    display: flex;
    gap: 0.5rem;
    align-items: center;
    flex-wrap: wrap;
}

#model-select {
    padding: 0.5rem 1rem;
    border: 2px solid var(--input-border);
    border-radius: 8px;
    font-size: 0.9rem;
    background: var(--input-bg);
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.2s;
    min-width: 200px;
}

#model-select:hover {
    border-color: var(--input-focus-border);
}

#model-select:focus {
    outline: none;
    border-color: var(--input-focus-border);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

#refresh-models, #clear-chat, #theme-toggle {
    padding: 0.5rem 1rem;
    border: 2px solid var(--input-border);
    border-radius: 8px;
    background: var(--input-bg);
    color: var(--text-primary);
    cursor: pointer;
    font-size: 1rem;
    transition: all 0.2s;
}

#refresh-models:hover, #clear-chat:hover, #theme-toggle:hover {
    background: var(--message-bot-bg);
    border-color: var(--input-focus-border);
    transform: translateY(-1px);
}

.status-bar {
    background: var(--status-bg);
    padding: 0.5rem 1.5rem;
    font-size: 0.85rem;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--status-border);
    min-height: 32px;
    display: flex;
    align-items: center;
    transition: background 0.3s ease, color 0.3s ease;
}

.status-bar.success {
    background: rgba(76, 175, 80, 0.1);
    color: #4caf50;
}

.status-bar.error {
    background: rgba(244, 67, 54, 0.1);
    color: #f44336;
}

.status-bar.info {
    background: rgba(33, 150, 243, 0.1);
    color: #2196f3;
}

#chat-container {
    flex: 1;
    overflow-y: auto;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    max-width: 1200px;
    width: 100%;
    margin: 0 auto;
}

#chat-history {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.message {
    padding: 1rem 1.25rem;
    border-radius: 12px;
    max-width: 80%;
    word-wrap: break-word;
    line-height: 1.6;
    animation: slideIn 0.3s ease-out;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

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

.user-message {
    background: var(--message-user-bg);
    color: white;
    align-self: flex-end;
    margin-left: auto;
}

.bot-message {
    background: var(--message-bot-bg);
    color: var(--text-primary);
    align-self: flex-start;
    border: 1px solid var(--message-bot-border);
    transition: background 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

.typing-indicator {
    display: flex;
    gap: 0.5rem;
    padding: 1rem;
    align-self: flex-start;
}

.typing-indicator span {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: #667eea;
    animation: typing 1.4s infinite;
}

.typing-indicator span:nth-child(2) {
    animation-delay: 0.2s;
}

.typing-indicator span:nth-child(3) {
    animation-delay: 0.4s;
}

@keyframes typing {
    0%, 60%, 100% {
        transform: translateY(0);
        opacity: 0.7;
    }
    30% {
        transform: translateY(-10px);
        opacity: 1;
    }
}

#input-container {
    background: var(--header-bg);
    backdrop-filter: blur(10px);
    padding: 1rem 1.5rem;
    box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.1);
    max-width: 1200px;
    width: 100%;
    margin: 0 auto;
    transition: background 0.3s ease;
}

#prompt-input {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid var(--input-border);
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    resize: vertical;
    min-height: 60px;
    max-height: 200px;
    transition: all 0.2s;
    background: var(--input-bg);
    color: var(--text-primary);
}

#prompt-input:focus {
    outline: none;
    border-color: var(--input-focus-border);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

#prompt-input::placeholder {
    color: var(--text-secondary);
    opacity: 0.7;
}

.input-actions {
    display: flex;
    justify-content: flex-end;
    margin-top: 0.5rem;
}

.send-button {
    padding: 0.75rem 2rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: 0 2px 8px rgba(102, 126, 234, 0.3);
}

.send-button:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

.send-button:active:not(:disabled) {
    transform: translateY(0);
}

.send-button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.empty-state {
    text-align: center;
    padding: 3rem;
    color: var(--empty-state-text);
    transition: color 0.3s ease;
}

.empty-state h2 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.empty-state p {
    opacity: 0.8;
}

/* Scrollbar styling */
#chat-container::-webkit-scrollbar {
    width: 8px;
}

#chat-container::-webkit-scrollbar-track {
    background: var(--scrollbar-track);
    border-radius: 4px;
}

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

#chat-container::-webkit-scrollbar-thumb:hover {
    background: var(--scrollbar-thumb);
    opacity: 0.8;
}

/* Responsive design */
@media (max-width: 768px) {
    .header {
        flex-direction: column;
        align-items: stretch;
    }
    
    .header-controls {
        width: 100%;
    }
    
    #model-select {
        flex: 1;
        min-width: 0;
    }
    
    .message {
        max-width: 90%;
    }
    
    #input-container {
        padding: 0.75rem 1rem;
    }
}