/* === CSS Reset & Base Styles === */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Color Palette */
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #64748b;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;

    /* Backgrounds */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --bg-chat: #f9fafb;

    /* Bot & User Message Colors */
    --bot-message-bg: #e0e7ff;
    --bot-message-text: #1e293b;
    --user-message-bg: #2563eb;
    --user-message-text: #ffffff;

    /* Text Colors */
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;

    /* Borders */
    --border-color: #e2e8f0;
    --border-radius: 12px;
    --border-radius-sm: 8px;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);

    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica', 'Arial', sans-serif;
    background: var(--bg-secondary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow: hidden;
}

/* === Container === */
.container {
    height: 100vh;
    display: flex;
    flex-direction: column;
    max-width: 1400px;
    margin: 0 auto;
}

/* === Header === */
.chat-header {
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-md) var(--spacing-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow-sm);
}

.chat-header h1 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.header-actions {
    display: flex;
    gap: var(--spacing-sm);
}

/* === Buttons === */
.btn-primary,
.btn-secondary {
    padding: var(--spacing-sm) var(--spacing-md);
    border: none;
    border-radius: var(--border-radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
}

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

.btn-primary:hover:not(:disabled) {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

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

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.btn-secondary:hover {
    background: var(--border-color);
}

/* === Chat Container === */
.chat-container {
    flex: 1;
    display: flex;
    overflow: hidden;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
}

/* === Progress Sidebar === */
.progress-sidebar {
    width: 300px;
    background: var(--bg-primary);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-md);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
    overflow-y: auto;
}

.progress-sidebar h2 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
}

/* Progress Bar */
.progress-bar {
    position: relative;
    height: 32px;
    background: var(--bg-tertiary);
    border-radius: 16px;
    overflow: hidden;
}

.progress-fill {
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), #3b82f6);
    border-radius: 16px;
    transition: width 0.3s ease;
    width: 0%;
}

.progress-text {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    font-weight: 600;
    font-size: 0.875rem;
    color: var(--text-primary);
    z-index: 1;
}

/* Data Checklist */
.data-checklist {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.data-checklist li {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm);
    border-radius: var(--border-radius-sm);
    transition: background 0.2s ease;
}

.data-checklist li:hover {
    background: var(--bg-tertiary);
}

.data-checklist li.collected {
    background: rgba(16, 185, 129, 0.1);
}

.checkbox {
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-color);
    border-radius: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    transition: all 0.2s ease;
}

.data-checklist li.collected .checkbox {
    background: var(--success-color);
    border-color: var(--success-color);
}

.data-checklist li.collected .checkbox::after {
    content: '✓';
    color: white;
    font-weight: bold;
    font-size: 0.875rem;
}

.label {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.data-checklist li.collected .label {
    color: var(--text-primary);
    font-weight: 500;
}

/* Conversation Stats */
.conversation-stats {
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.stat-item {
    display: flex;
    justify-content: space-between;
    font-size: 0.875rem;
}

.stat-label {
    color: var(--text-secondary);
}

.stat-value {
    font-weight: 600;
    color: var(--text-primary);
}

/* === Chat Main Area === */
.chat-main {
    flex: 1;
    background: var(--bg-primary);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

/* Messages Container */
.messages-container {
    flex: 1;
    overflow-y: auto;
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    scroll-behavior: smooth;
}

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

.messages-container::-webkit-scrollbar-track {
    background: var(--bg-tertiary);
    border-radius: 4px;
}

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

.messages-container::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

/* Message Bubbles */
.message {
    max-width: 70%;
    animation: fadeIn 0.3s ease;
}

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

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

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

.message-content {
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    word-wrap: break-word;
}

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

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

.message-content p {
    margin: 0;
    line-height: 1.5;
}

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

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

/* Typing Indicator */
.typing-indicator {
    display: none;
    align-items: center;
    gap: 4px;
    padding: var(--spacing-md);
    margin: 0 var(--spacing-lg);
    background: var(--bot-message-bg);
    border-radius: var(--border-radius);
    width: fit-content;
    max-width: 70%;
}

.typing-indicator.active {
    display: flex;
}

.typing-indicator span {
    width: 8px;
    height: 8px;
    background: var(--secondary-color);
    border-radius: 50%;
    animation: bounce 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 bounce {
    0%, 80%, 100% {
        transform: scale(0);
        opacity: 0.5;
    }
    40% {
        transform: scale(1);
        opacity: 1;
    }
}

/* === Input Container === */
.input-container {
    padding: var(--spacing-lg);
    border-top: 1px solid var(--border-color);
    display: flex;
    gap: var(--spacing-sm);
    background: var(--bg-secondary);
}

#user-input {
    flex: 1;
    padding: var(--spacing-md);
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    font-family: inherit;
    font-size: 0.9375rem;
    resize: none;
    outline: none;
    transition: all 0.2s ease;
    max-height: 120px;
    overflow-y: auto;
}

#user-input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

#send-btn {
    width: 48px;
    height: 48px;
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    border-radius: 50%;
}

#send-btn svg {
    width: 20px;
    height: 20px;
}

/* === Responsive Design === */
@media (max-width: 768px) {
    .chat-container {
        flex-direction: column;
    }

    .progress-sidebar {
        width: 100%;
        max-height: 200px;
        order: 2;
    }

    .chat-main {
        order: 1;
        min-height: 500px;
    }

    .message {
        max-width: 85%;
    }

    .chat-header h1 {
        font-size: 1.25rem;
    }
}

@media (max-width: 480px) {
    .chat-header {
        padding: var(--spacing-sm) var(--spacing-md);
    }

    .messages-container,
    .progress-sidebar,
    .input-container {
        padding: var(--spacing-md);
    }

    .btn-secondary {
        font-size: 0.75rem;
        padding: var(--spacing-xs) var(--spacing-sm);
    }
}

/* === Utility Classes === */
.hidden {
    display: none !important;
}

.error {
    color: var(--danger-color);
    background: rgba(239, 68, 68, 0.1);
    padding: var(--spacing-sm);
    border-radius: var(--border-radius-sm);
    font-size: 0.875rem;
}