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

:root {
    /* Colors */
    --primary-color: #6366f1;
    --primary-hover: #5855eb;
    --primary-light: #e0e7ff;
    --secondary-color: #f8fafc;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    --border-color: #e2e8f0;
    --border-light: #f1f5f9;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    --white: #ffffff;
    --gray-50: #f8fafc;
    --gray-100: #f1f5f9;
    --gray-200: #e2e8f0;
    --gray-300: #cbd5e1;
    --gray-400: #94a3b8;
    --gray-500: #64748b;
    --gray-600: #475569;
    --gray-700: #334155;
    --gray-800: #1e293b;
    --gray-900: #0f172a;
    
    /* Typography */
    --font-family-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-family-heading: 'Poppins', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    --spacing-4xl: 6rem;
    
    /* Layout */
    --sidebar-width: 320px;
    --details-width: 280px;
    --border-radius: 0.5rem;
    --border-radius-lg: 0.75rem;
    --border-radius-xl: 1rem;
    
    /* 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), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    
    /* Transitions */
    --transition-base: all 0.2s ease-in-out;
}

body {
    font-family: var(--font-family-primary);
    background-color: var(--gray-50);
    color: var(--text-primary);
    line-height: 1.5;
    font-size: 16px;
    height: 100vh;
    overflow: hidden;
}

/* === Header === */
.inbox-header {
    background: var(--white);
    border-bottom: 1px solid var(--border-light);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    height: 60px;
}

.header-container {
    height: 100%;
    max-width: none;
    margin: 0;
    padding: 0 var(--spacing-xl);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

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

.logo-icon {
    width: 28px;
    height: 28px;
    color: var(--primary-color);
}

.logo-text {
    font-family: var(--font-family-heading);
    font-size: 18px;
    font-weight: 600;
    color: var(--text-primary);
}

.main-nav {
    display: flex;
    gap: var(--spacing-xl);
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    padding: var(--spacing-sm) 0;
    border-bottom: 2px solid transparent;
    transition: var(--transition-base);
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

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

.user-avatars {
    display: flex;
    gap: var(--spacing-xs);
}

.avatar-small {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--gray-300);
    border: 2px solid var(--white);
}

.help-text {
    color: var(--text-secondary);
    font-size: 14px;
}

.upgrade-btn {
    background: var(--primary-color);
    border: none;
    border-radius: var(--border-radius);
    padding: var(--spacing-sm) var(--spacing-md);
    color: var(--white);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-base);
    font-size: 14px;
}

.upgrade-btn:hover {
    background: var(--primary-hover);
}

/* === Main Layout === */
.inbox-main {
    margin-top: 60px;
    height: calc(100vh - 60px);
    overflow: hidden;
}

.inbox-container {
    height: 100%;
    display: grid;
    grid-template-columns: var(--sidebar-width) 1fr var(--details-width);
}

/* === Sidebar === */
.inbox-sidebar {
    background: var(--white);
    border-right: 1px solid var(--border-light);
    display: flex;
    flex-direction: column;
    height: 100%;
}

.inbox-tabs {
    display: flex;
    border-bottom: 1px solid var(--border-light);
    padding: 0 var(--spacing-md);
}

.tab-btn {
    background: none;
    border: none;
    padding: var(--spacing-md) var(--spacing-lg);
    font-size: 14px;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    border-bottom: 2px solid transparent;
    transition: var(--transition-base);
}

.tab-btn:hover,
.tab-btn.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

.conversations-list {
    flex: 1;
    overflow-y: auto;
    padding: var(--spacing-sm) 0;
}

.conversation-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
    cursor: pointer;
    transition: var(--transition-base);
    border-left: 3px solid transparent;
}

.conversation-item:hover {
    background: var(--gray-50);
}

.conversation-item.active {
    background: var(--primary-light);
    border-left-color: var(--primary-color);
}

.conversation-avatar {
    flex-shrink: 0;
}

.conversation-avatar img {
    width: 40px;
    height: 40px;
    border-radius: 50%;
}

.conversation-info {
    flex: 1;
    min-width: 0;
}

.conversation-name {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 2px;
}

.conversation-preview {
    font-size: 13px;
    color: var(--text-secondary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.conversation-meta {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: var(--spacing-xs);
    flex-shrink: 0;
}

.conversation-time {
    font-size: 12px;
    color: var(--text-muted);
}

.conversation-badge {
    background: var(--primary-color);
    color: var(--white);
    font-size: 11px;
    font-weight: 600;
    padding: 2px 6px;
    border-radius: 10px;
    min-width: 18px;
    text-align: center;
}

.sidebar-footer {
    padding: var(--spacing-lg);
    border-top: 1px solid var(--border-light);
    text-align: center;
}

.empty-state-text {
    font-size: 14px;
    color: var(--text-muted);
}

/* === Chat Area === */
.chat-area {
    background: var(--white);
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100%;
    border-right: 1px solid var(--border-light);
}

.empty-state {
    text-align: center;
    max-width: 400px;
    padding: var(--spacing-xl);
}

.empty-state-illustration {
    margin-bottom: var(--spacing-xl);
}

.empty-state-illustration svg {
    width: 200px;
    height: 200px;
}

.empty-state-content h2 {
    font-size: 20px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
    line-height: 1.3;
}

.empty-state-content p {
    font-size: 16px;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
}

.upgrade-cta-btn {
    background: var(--primary-color);
    border: none;
    border-radius: var(--border-radius);
    padding: var(--spacing-md) var(--spacing-lg);
    color: var(--white);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-base);
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 14px;
}

.upgrade-cta-btn:hover {
    background: var(--primary-hover);
}

.upgrade-cta-btn svg {
    width: 16px;
    height: 16px;
}

/* === Chat Details === */
.chat-details {
    background: var(--gray-50);
    border-left: 1px solid var(--border-light);
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.details-content {
    padding: var(--spacing-xl);
    text-align: center;
}

.details-placeholder {
    font-size: 14px;
    color: var(--text-muted);
}

/* === Chat Widget === */
.chat-widget {
    position: fixed;
    bottom: var(--spacing-xl);
    right: var(--spacing-xl);
    z-index: 1000;
}

.chat-button {
    background: var(--primary-color);
    border: none;
    border-radius: 50%;
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition-base);
    box-shadow: var(--shadow-lg);
}

.chat-button:hover {
    background: var(--primary-hover);
    transform: scale(1.05);
}

.chat-button svg {
    width: 24px;
    height: 24px;
    color: var(--white);
}

/* === Active Chat State === */
.chat-header {
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--border-light);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.chat-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--primary-color);
}

.chat-info h3 {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 2px;
}

.chat-info p {
    font-size: 14px;
    color: var(--text-secondary);
}

.chat-messages {
    flex: 1;
    padding: var(--spacing-lg);
    overflow-y: auto;
}

.message {
    margin-bottom: var(--spacing-lg);
}

.message.sent {
    text-align: right;
}

.message-bubble {
    display: inline-block;
    max-width: 70%;
    padding: var(--spacing-md);
    border-radius: var(--border-radius-lg);
    background: var(--gray-100);
    color: var(--text-primary);
}

.message.sent .message-bubble {
    background: var(--primary-color);
    color: var(--white);
}

.message-time {
    font-size: 12px;
    color: var(--text-muted);
    margin-top: var(--spacing-xs);
}

.chat-input {
    padding: var(--spacing-lg);
    border-top: 1px solid var(--border-light);
}

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

.message-input {
    flex: 1;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-md);
    resize: none;
    font-family: inherit;
    font-size: 14px;
    max-height: 120px;
}

.send-btn {
    background: var(--primary-color);
    border: none;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition-base);
    color: var(--white);
}

.send-btn:hover {
    background: var(--primary-hover);
}

/* === Responsive Design === */
@media (max-width: 1024px) {
    .inbox-container {
        grid-template-columns: var(--sidebar-width) 1fr;
    }
    
    .chat-details {
        display: none;
    }
}

@media (max-width: 768px) {
    .header-container {
        padding: 0 var(--spacing-md);
    }
    
    .main-nav {
        display: none;
    }
    
    .help-text {
        display: none;
    }
    
    .user-avatars {
        display: none;
    }
    
    :root {
        --sidebar-width: 280px;
    }
}

@media (max-width: 640px) {
    .inbox-container {
        grid-template-columns: 1fr;
    }
    
    .inbox-sidebar {
        position: fixed;
        top: 60px;
        left: -100%;
        width: 280px;
        height: calc(100vh - 60px);
        z-index: 200;
        transition: left 0.3s ease;
    }
    
    .inbox-sidebar.open {
        left: 0;
    }
    
    .chat-area {
        grid-column: 1;
    }
    
    .chat-widget {
        bottom: var(--spacing-md);
        right: var(--spacing-md);
    }
    
    .header-actions {
        gap: var(--spacing-sm);
    }
}

/* === Scrollbar Styling === */
.conversations-list::-webkit-scrollbar {
    width: 4px;
}

.conversations-list::-webkit-scrollbar-track {
    background: transparent;
}

.conversations-list::-webkit-scrollbar-thumb {
    background: var(--gray-300);
    border-radius: 2px;
}

.conversations-list::-webkit-scrollbar-thumb:hover {
    background: var(--gray-400);
}