/* ===================================
   Anonymous Chat - Main Styles
   Modern, Responsive, Minimalistic
   =================================== */

/* CSS Variables */
:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --secondary-color: #64748b;
    --success-color: #22c55e;
    --error-color: #ef4444;
    --warning-color: #f59e0b;
    
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-tertiary: #f1f5f9;
    
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
    
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-full: 9999px;
    
    --transition: all 0.2s ease;
    
    --sent-bg: #6366f1;
    --sent-text: #ffffff;
    --received-bg: #f1f5f9;
    --received-text: #1e293b;
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html, body {
    height: 100%;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    font-size: 14px;
    line-height: 1.5;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    -webkit-font-smoothing: antialiased;
}

/* App Container */
.app-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
    max-width: 1400px;
    margin: 0 auto;
    background: var(--bg-secondary);
    box-shadow: var(--shadow-lg);
}

/* Header */
.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 24px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    z-index: 100;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 12px;
}

.header-left h1 {
    font-size: 20px;
    font-weight: 600;
    color: var(--primary-color);
    margin: 0;
}

.header-left .user-info {
    font-size: 13px;
    color: var(--text-secondary);
    margin-left: 12px;
}

.header-left .user-info strong {
    color: var(--text-primary);
}

.header-right {
    display: flex;
    align-items: center;
    gap: 8px;
}

/* Login Button in Header */
.btn-login {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 14px;
    border: none;
    border-radius: var(--radius-md);
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

.btn-login:hover {
    background: var(--border-color);
    color: var(--text-primary);
}

.btn-login span {
    display: inline;
}

/* Back Link */
.back-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: var(--radius-md);
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
}

.back-link:hover {
    background: var(--border-color);
    color: var(--text-primary);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    border: none;
    border-radius: var(--radius-md);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
}

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

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

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

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

.btn-topics {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    text-decoration: none;
}

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

.btn-icon, .btn-refresh {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border: none;
    border-radius: var(--radius-md);
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
}

.btn-icon:hover, .btn-refresh:hover {
    background: var(--border-color);
    color: var(--text-primary);
}

/* Main Content */
.main-content {
    display: flex;
    flex: 1;
    overflow: hidden;
}

/* User List Panel */
.user-list-panel {
    width: 300px;
    min-width: 280px;
    display: flex;
    flex-direction: column;
    border-right: 1px solid var(--border-color);
    background: var(--bg-secondary);
}

.panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
}

.panel-header h2 {
    font-size: 16px;
    font-weight: 600;
    margin: 0;
}

.user-list {
    flex: 1;
    overflow-y: auto;
    padding: 12px;
}

.loading {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 40px 20px;
    color: var(--text-muted);
}

/* User Item */
.user-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 16px;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition);
    margin-bottom: 4px;
}

.user-item:hover {
    background: var(--bg-tertiary);
}

.user-item.active {
    background: rgba(99, 102, 241, 0.1);
}

.user-item .user-avatar {
    width: 44px;
    height: 44px;
    border-radius: var(--radius-full);
    background: linear-gradient(135deg, var(--primary-color), #818cf8);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 600;
    font-size: 16px;
    flex-shrink: 0;
}

.user-item .user-details {
    flex: 1;
    min-width: 0;
}

.user-item .user-name {
    display: block;
    font-weight: 500;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.user-item .user-status {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 12px;
    color: var(--text-secondary);
}

.user-status .status-dot {
    width: 8px;
    height: 8px;
    border-radius: var(--radius-full);
    background: var(--text-muted);
}

.user-status .status-dot.online {
    background: var(--success-color);
}

.user-item .unread-badge {
    min-width: 20px;
    height: 20px;
    padding: 0 6px;
    border-radius: var(--radius-full);
    background: var(--primary-color);
    color: white;
    font-size: 11px;
    font-weight: 600;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Chat Panel */
.chat-panel {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: var(--bg-tertiary);
    min-width: 0;
}

/* Empty State */
.empty-state {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 40px;
    text-align: center;
}

.empty-icon {
    margin-bottom: 24px;
    color: var(--text-muted);
    opacity: 0.5;
}

.empty-state h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.empty-state p {
    color: var(--text-secondary);
    max-width: 300px;
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    animation: fadeIn 0.2s ease;
}

.modal.hidden {
    display: none;
}

.modal-content {
    width: 90%;
    max-width: 400px;
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 24px;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    font-size: 18px;
    font-weight: 600;
    margin: 0;
}

.btn-close-modal {
    width: 32px;
    height: 32px;
    border: none;
    border-radius: var(--radius-md);
    background: transparent;
    font-size: 24px;
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
}

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

.modal-body {
    padding: 24px;
}

.modal-body p {
    color: var(--text-secondary);
    margin: 0;
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: 12px;
    padding: 16px 24px;
    background: var(--bg-tertiary);
}

.modal-footer .btn {
    text-decoration: none;
}

/* Input Fields */
.input-field {
    width: 100%;
    padding: 14px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 14px;
    outline: none;
    transition: var(--transition);
    background: var(--bg-secondary);
}

.input-field:focus {
    border-color: var(--primary-color);
}

/* Toast */
.toast-container {
    position: fixed;
    bottom: 24px;
    right: 24px;
    display: flex;
    flex-direction: column;
    gap: 12px;
    z-index: 2000;
}

.toast {
    padding: 14px 20px;
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    border-left: 4px solid var(--primary-color);
    animation: slideIn 0.3s ease;
    max-width: 350px;
}

@keyframes slideIn {
    from { transform: translateX(100%); opacity: 0; }
    to { transform: translateX(0); opacity: 1; }
}

.toast.error {
    border-left-color: var(--error-color);
}

.toast.success {
    border-left-color: var(--success-color);
}

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

/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

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

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* Responsive */
@media (max-width: 768px) {
    .user-list-panel {
        width: 100%;
        position: absolute;
        left: 0;
        right: 0;
        height: calc(100% - 70px);
        z-index: 50;
    }
    
    .chat-view.active ~ .user-list-panel {
        display: none;
    }
    
    .app-header {
        padding: 12px 16px;
    }
    
    .header-left h1 {
        font-size: 18px;
    }
    
    .header-left .user-info {
        display: none;
    }
    
    .btn-topics span {
        display: none;
    }
    
    .btn-login span {
        display: none;
    }
}

@media (max-width: 480px) {
    .empty-state h3 {
        font-size: 16px;
    }
}

/* ===================================
   Welcome Modal Styles
   =================================== */

.welcome-modal-content {
    max-width: 420px;
}

.welcome-icon {
    display: flex;
    justify-content: center;
    margin-bottom: 16px;
    color: var(--primary-color);
}

.welcome-text {
    text-align: center;
    font-size: 16px;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 20px;
}

.account-info {
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    padding: 16px;
    margin-bottom: 16px;
}

.info-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 0;
}

.info-row:not(:last-child) {
    border-bottom: 1px solid var(--border-color);
}

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

.info-value {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
}

.password-value {
    color: var(--primary-color);
    font-family: monospace;
    font-size: 18px;
    letter-spacing: 2px;
}

.notice-box {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    padding: 12px 16px;
    background: rgba(245, 158, 11, 0.1);
    border-radius: var(--radius-md);
    color: var(--warning-color);
    font-size: 13px;
    line-height: 1.5;
}

.notice-box svg {
    flex-shrink: 0;
    margin-top: 2px;
}

/* ===================================
   Login Modal Styles
   =================================== */

.login-subtitle {
    color: var(--text-secondary);
    font-size: 14px;
    margin-bottom: 20px;
}

.form-group {
    margin-bottom: 16px;
}

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.login-error {
    padding: 12px;
    background: rgba(239, 68, 68, 0.1);
    border-radius: var(--radius-md);
    color: var(--error-color);
    font-size: 14px;
    margin-top: 12px;
}

.login-error.hidden {
    display: none;
}

/* App loading state */
.app-loading {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--bg-primary);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 9999;
}

.app-loading .spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 16px;
}

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

@keyframes spin {
    to { transform: rotate(360deg); }
}