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

:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary: #ec4899;
    --bg: #f8fafc;
    --surface: #ffffff;
    --surface-secondary: #f1f5f9;
    --text: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --border: #e2e8f0;
    --online: #22c55e;
    --offline: #94a3b8;
    --shadow-sm: 0 1px 2px 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);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    height: 100vh;
    overflow: hidden;
    color: var(--text);
}

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

.screen {
    display: none;
    height: 100vh;
    width: 100%;
}

.screen.active {
    display: block;
}

/* Auth Screen - Centered */
.auth-screen {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex !important;
    align-items: center !important;
    justify-content: center !important;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    z-index: 1000;
}

.auth-card {
    background: rgba(255,255,255,0.98);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-xl);
    padding: 40px 32px;
    width: 100%;
    max-width: 440px;
    margin: 20px;
    box-shadow: var(--shadow-lg);
    animation: fadeIn 0.4s ease;
}

.auth-header {
    text-align: center;
    margin-bottom: 32px;
}

.logo-icon {
    font-size: 48px;
    margin-bottom: 12px;
}

.logo-text {
    font-size: 28px;
    font-weight: 700;
    background: linear-gradient(135deg, #667eea, #764ba2);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.logo-subtitle {
    font-size: 14px;
    color: var(--text-secondary);
    margin-top: 8px;
}

.auth-form {
    display: none;
    animation: fadeIn 0.3s ease;
}

.auth-form.active {
    display: block;
}

.input-group {
    position: relative;
    margin-bottom: 16px;
}

.input-icon {
    position: absolute;
    left: 16px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
}

.input-field {
    width: 100%;
    padding: 14px 16px 14px 48px;
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    font-size: 15px;
    transition: all 0.2s;
    background: var(--surface);
}

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

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 10px;
    margin: 20px 0;
    cursor: pointer;
}

.btn {
    width: 100%;
    padding: 14px;
    border: none;
    border-radius: var(--radius-md);
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    transition: all 0.2s;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.auth-switch {
    text-align: center;
    margin-top: 24px;
    font-size: 14px;
    color: var(--text-secondary);
}

.auth-switch a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 600;
}

/* Main Screen */
.main-screen {
    background: var(--bg);
}

/* Mobile Header */
.mobile-header {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--surface);
    padding: 12px 16px;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--border);
    z-index: 100;
}

/* Chats Panel */
.chats-panel {
    width: 320px;
    background: var(--surface);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    height: 100vh;
    position: fixed;
    left: 0;
    top: 0;
    transition: transform 0.3s ease;
    z-index: 50;
}

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

.user-profile {
    display: flex;
    align-items: center;
    gap: 12px;
    cursor: pointer;
}

.user-avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
}

.user-name {
    font-weight: 600;
}

.user-status {
    font-size: 12px;
    color: var(--online);
}

.icon-btn {
    background: none;
    border: none;
    font-size: 18px;
    cursor: pointer;
    padding: 8px;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
}

.search-chats {
    padding: 12px 20px;
    position: relative;
}

.search-chats .search-icon {
    position: absolute;
    left: 32px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
}

.search-chats .search-input {
    width: 100%;
    padding: 10px 12px 10px 36px;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    background: var(--surface-secondary);
}

.chats-list {
    flex: 1;
    overflow-y: auto;
}

.chat-item {
    display: flex;
    align-items: center;
    padding: 12px 20px;
    cursor: pointer;
    gap: 12px;
    transition: background 0.2s;
}

.chat-item:hover {
    background: var(--surface-secondary);
}

.chat-item.active {
    background: linear-gradient(135deg, rgba(99,102,241,0.1), rgba(118,75,162,0.1));
    border-left: 3px solid var(--primary);
}

.chat-avatar {
    width: 52px;
    height: 52px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    color: white;
    flex-shrink: 0;
}

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

.chat-name {
    font-weight: 600;
    margin-bottom: 4px;
}

.chat-last-message {
    font-size: 13px;
    color: var(--text-muted);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.chat-meta {
    text-align: right;
    flex-shrink: 0;
}

.chat-time {
    font-size: 11px;
    color: var(--text-muted);
}

.unread-badge {
    background: var(--primary);
    color: white;
    font-size: 11px;
    padding: 2px 8px;
    border-radius: 20px;
}

/* Chat Panel */
.chat-panel {
    margin-left: 320px;
    height: 100vh;
    display: flex;
    flex-direction: column;
    background: var(--bg);
}

.chat-header {
    padding: 16px 20px;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    gap: 16px;
}

.back-btn {
    display: none;
    background: none;
    border: none;
    font-size: 20px;
    cursor: pointer;
}

.messages-area {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.message {
    display: flex;
    margin-bottom: 8px;
    animation: fadeIn 0.2s ease;
}

.message.own {
    justify-content: flex-end;
}

.message-content {
    max-width: 70%;
    padding: 10px 14px;
    border-radius: 20px;
    word-wrap: break-word;
}

.message:not(.own) .message-content {
    background: var(--surface);
    border-bottom-left-radius: 4px;
}

.message.own .message-content {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    border-bottom-right-radius: 4px;
}

.message-time {
    font-size: 10px;
    margin-top: 4px;
    margin-left: 12px;
    color: var(--text-muted);
}

.message-input-container {
    padding: 16px 20px;
    background: var(--surface);
    border-top: 1px solid var(--border);
}

.input-wrapper {
    display: flex;
    gap: 12px;
    align-items: center;
}

.message-input-field {
    flex: 1;
    padding: 12px 16px;
    border: 1px solid var(--border);
    border-radius: 28px;
    background: var(--surface-secondary);
}

.send-btn {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    border: none;
    border-radius: 50%;
    width: 44px;
    height: 44px;
    cursor: pointer;
    color: white;
}

/* Profile Panel */
.profile-panel {
    position: fixed;
    right: -100%;
    top: 0;
    width: 320px;
    height: 100vh;
    background: var(--surface);
    border-left: 1px solid var(--border);
    transition: right 0.3s ease;
    z-index: 200;
}

.profile-panel.open {
    right: 0;
}

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

.close-profile-btn {
    background: none;
    border: none;
    font-size: 20px;
    cursor: pointer;
}

.profile-content {
    padding: 20px;
    text-align: center;
}

.profile-avatar {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 40px;
    margin: 0 auto 20px;
    color: white;
}

/* Modals */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0,0,0,0.5);
    z-index: 1000;
    align-items: center;
    justify-content: center;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: var(--surface);
    border-radius: var(--radius-lg);
    width: 90%;
    max-width: 400px;
    max-height: 80vh;
    overflow: hidden;
}

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

.modal-body {
    padding: 20px;
    overflow-y: auto;
}

/* Toast */
.toast {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(0,0,0,0.8);
    color: white;
    padding: 12px 20px;
    border-radius: 40px;
    font-size: 14px;
    z-index: 1100;
    opacity: 0;
    transition: opacity 0.3s;
    pointer-events: none;
}

.toast.show {
    opacity: 1;
}

.loading-spinner {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 40px;
    color: var(--text-muted);
}

/* Mobile */
@media (max-width: 768px) {
    .mobile-header {
        display: flex;
    }
    
    .chats-panel {
        transform: translateX(-100%);
        width: 85%;
        z-index: 150;
    }
    
    .chats-panel.open {
        transform: translateX(0);
    }
    
    .chat-panel {
        margin-left: 0;
    }
    
    .back-btn {
        display: flex;
    }
    
    .profile-panel {
        width: 85%;
    }
    
    .message-content {
        max-width: 85%;
    }
    
    /* Принудительное переключение экранов */
#authScreen {
    transition: display 0s;
}

#authScreen[style*="display: none"],
.auth-screen[style*="display: none"] {
    display: none !important;
}

#appScreen[style*="display: block"],
.main-screen[style*="display: block"] {
    display: block !important;
}

.screen.main-screen.active {
    display: block !important;
}
}