/* ===========================
   CSS Variables & Reset
   =========================== */
:root {
    /* Colors */
    --primary: #6366f1;
    --primary-light: #818cf8;
    --secondary: #8b5cf6;
    --accent: #ec4899;
    --bg-dark: #0f172a;
    --bg-darker: #020617;
    --bg-card: rgba(30, 41, 59, 0.6);
    --bg-card-hover: rgba(30, 41, 59, 0.8);
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --border: rgba(148, 163, 184, 0.1);
    --shadow: rgba(0, 0, 0, 0.3);
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
    --gradient-user: linear-gradient(135deg, #3b82f6 0%, #6366f1 100%);
    --gradient-bot: linear-gradient(135deg, #8b5cf6 0%, #ec4899 100%);
    --gradient-bg: linear-gradient(135deg, #0f172a 0%, #1e1b4b 100%);
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 0.75rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    
    /* Border Radius */
    --radius-sm: 0.5rem;
    --radius-md: 1rem;
    --radius-lg: 1.5rem;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--gradient-bg);
    color: var(--text-primary);
    min-height: 100vh;
    overflow: hidden;
    position: relative;
}

/* Animated Background */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 20% 50%, rgba(99, 102, 241, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(139, 92, 246, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 40% 20%, rgba(236, 72, 153, 0.05) 0%, transparent 50%);
    animation: backgroundPulse 15s ease-in-out infinite;
    pointer-events: none;
    z-index: 0;
}

@keyframes backgroundPulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.8; }
}

/* ===========================
   Container & Layout
   =========================== */
.container {
    position: relative;
    z-index: 1;
    max-width: 1200px;
    margin: 0 auto;
    height: 100vh;
    display: flex;
    flex-direction: column;
    padding: var(--spacing-lg);
    gap: var(--spacing-lg);
}

/* ===========================
   Header
   =========================== */
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-lg);
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    box-shadow: 0 8px 32px var(--shadow);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.logo-icon {
    font-size: 2.5rem;
    background: var(--gradient-primary);
    width: 60px;
    height: 60px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 20px rgba(99, 102, 241, 0.4);
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-10px); }
}

.logo-text {
    font-size: 2rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.download-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--gradient-primary);
    color: white;
    border: none;
    border-radius: var(--radius-full);
    font-weight: 600;
    font-size: 0.95rem;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
}

.download-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px rgba(99, 102, 241, 0.5);
}

.download-btn:active {
    transform: translateY(0);
}

.download-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

/* ===========================
   Chat Container
   =========================== */
.chat-container {
    flex: 1;
    overflow-y: auto;
    padding: var(--spacing-xl);
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    box-shadow: 0 8px 32px var(--shadow);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

/* Custom Scrollbar */
.chat-container::-webkit-scrollbar {
    width: 8px;
}

.chat-container::-webkit-scrollbar-track {
    background: rgba(148, 163, 184, 0.1);
    border-radius: var(--radius-full);
}

.chat-container::-webkit-scrollbar-thumb {
    background: var(--gradient-primary);
    border-radius: var(--radius-full);
}

.chat-container::-webkit-scrollbar-thumb:hover {
    background: var(--primary-light);
}

/* ===========================
   Welcome Message
   =========================== */
.welcome-message {
    text-align: center;
    padding: var(--spacing-xl);
    animation: fadeInUp 0.6s ease-out;
}

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

.bot-avatar-large {
    position: relative;
    font-size: 5rem;
    margin: 0 auto var(--spacing-lg);
    width: 120px;
    height: 120px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.avatar-glow {
    position: absolute;
    width: 100%;
    height: 100%;
    background: var(--gradient-primary);
    border-radius: 50%;
    filter: blur(30px);
    opacity: 0.5;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); opacity: 0.5; }
    50% { transform: scale(1.1); opacity: 0.7; }
}

.welcome-message h2 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.welcome-message p {
    color: var(--text-secondary);
    font-size: 1.1rem;
    line-height: 1.6;
    max-width: 600px;
    margin: 0 auto;
}

/* ===========================
   Messages
   =========================== */
.message {
    display: flex;
    gap: var(--spacing-md);
    animation: slideIn 0.4s ease-out;
    max-width: 85%;
}

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

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

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

.avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    flex-shrink: 0;
    background: var(--gradient-primary);
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
}

.user-message .avatar {
    background: var(--gradient-user);
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.3);
}

.message-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.message-text {
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    font-size: 1rem;
    line-height: 1.6;
    white-space: pre-wrap;
    word-wrap: break-word;
    overflow-wrap: break-word;
}

.user-message .message-text {
    background: var(--gradient-user);
    color: white;
    border-bottom-right-radius: 0.25rem;
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.2);
}

.bot-message .message-text {
    background: var(--gradient-bot);
    color: white;
    border-bottom-left-radius: 0.25rem;
    box-shadow: 0 4px 15px rgba(139, 92, 246, 0.2);
}

.timestamp {
    font-size: 0.75rem;
    color: var(--text-muted);
    padding: 0 var(--spacing-sm);
}

.user-message .timestamp {
    text-align: right;
}

/* ===========================
   Typing Indicator
   =========================== */
.typing-indicator .message-content {
    background: var(--bg-card-hover);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    width: fit-content;
}

.typing-dots {
    display: flex;
    gap: 6px;
    padding: 4px 0;
}

.typing-dots span {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--primary);
    animation: typingBounce 1.4s infinite;
}

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

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

@keyframes typingBounce {
    0%, 60%, 100% { transform: translateY(0); }
    30% { transform: translateY(-10px); }
}

/* ===========================
   Input Area
   =========================== */
.input-area {
    padding: var(--spacing-lg);
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    box-shadow: 0 8px 32px var(--shadow);
}

.input-wrapper {
    display: flex;
    gap: var(--spacing-md);
    align-items: flex-end;
}

.message-input {
    flex: 1;
    padding: var(--spacing-md) var(--spacing-lg);
    background: rgba(15, 23, 42, 0.5);
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 1rem;
    line-height: 1.5;
    resize: none;
    max-height: 150px;
    transition: var(--transition);
}

.message-input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.message-input::placeholder {
    color: var(--text-muted);
}

.send-btn {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: var(--gradient-primary);
    border: none;
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
    flex-shrink: 0;
}

.send-btn:hover:not(:disabled) {
    transform: scale(1.05);
    box-shadow: 0 6px 25px rgba(99, 102, 241, 0.5);
}

.send-btn:active:not(:disabled) {
    transform: scale(0.95);
}

.send-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.input-hint {
    margin-top: var(--spacing-sm);
    font-size: 0.85rem;
    color: var(--text-muted);
    text-align: center;
}

/* ===========================
   Responsive Design
   =========================== */
@media (max-width: 768px) {
    .container {
        padding: var(--spacing-md);
        gap: var(--spacing-md);
    }
    
    .header {
        padding: var(--spacing-md);
        flex-direction: column;
        gap: var(--spacing-md);
    }
    
    .logo-icon {
        width: 50px;
        height: 50px;
        font-size: 2rem;
    }
    
    .logo-text {
        font-size: 1.5rem;
    }
    
    .download-btn span {
        display: none;
    }
    
    .chat-container {
        padding: var(--spacing-md);
    }
    
    .message {
        max-width: 90%;
    }
    
    .welcome-message h2 {
        font-size: 1.5rem;
    }
    
    .welcome-message p {
        font-size: 1rem;
    }
    
    .bot-avatar-large {
        font-size: 4rem;
        width: 100px;
        height: 100px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: var(--spacing-sm);
    }
    
    .message {
        max-width: 95%;
    }
    
    .avatar {
        width: 35px;
        height: 35px;
        font-size: 1.2rem;
    }
    
    .message-text {
        font-size: 0.95rem;
    }
}