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

:root {
    --primary-color: #1a365d;
    --secondary-color: #2d3748;
    --accent-color: #3182ce;
    --success-color: #38a169;
    --warning-color: #d69e2e;
    --danger-color: #e53e3e;
    --light-color: #f7fafc;
    --dark-color: #2d3748;
    --gray-color: #a0aec0;
    --border-color: #e2e8f0;
    
    --shadow: 0 2px 4px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1);
    --transition: all 0.3s ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    line-height: 1.6;
    color: var(--dark-color);
    background-color: var(--light-color);
    overflow-x: hidden;
}

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

/* Loading Screen */
.loading-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.loading-content {
    text-align: center;
    color: white;
}

.loading-logo {
    margin-bottom: 2rem;
}

.loading-logo i {
    font-size: 4rem;
    margin-bottom: 1rem;
}

.loading-logo h1 {
    font-size: 2rem;
    font-weight: 600;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid rgba(255,255,255,0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 1s ease-in-out infinite;
    margin: 2rem auto;
}

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

/* Screens */
.screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow-y: auto;
}

/* Authentication Screen */
.auth-screen {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 1rem;
}

.auth-container {
    background: white;
    border-radius: 20px;
    padding: 2rem;
    width: 100%;
    max-width: 400px;
    box-shadow: var(--shadow-lg);
}

.auth-header {
    text-align: center;
    margin-bottom: 2rem;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}

.logo i {
    font-size: 2rem;
    color: var(--primary-color);
}

.logo h1 {
    font-size: 1.5rem;
    color: var(--primary-color);
}

.tagline {
    color: var(--gray-color);
    font-size: 0.9rem;
}

.auth-form {
    animation: slideIn 0.3s ease;
}

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

.input-group {
    margin-bottom: 1.5rem;
}

.input-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--dark-color);
}

.input-group label i {
    margin-right: 0.5rem;
    color: var(--gray-color);
}

.input-group input {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    font-size: 1rem;
    transition: var(--transition);
}

.input-group input:focus {
    outline: none;
    border-color: var(--accent-color);
}

.auth-switch {
    text-align: center;
    margin-top: 1rem;
    color: var(--gray-color);
}

.auth-switch a {
    color: var(--accent-color);
    text-decoration: none;
    font-weight: 500;
}

/* Buttons */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
    width: 100%;
}

.btn-primary:hover {
    background-color: var(--secondary-color);
    transform: translateY(-2px);
}

.btn-secondary {
    background-color: var(--light-color);
    color: var(--dark-color);
    border: 2px solid var(--border-color);
}

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

.btn-success {
    background-color: var(--success-color);
    color: white;
    width: 100%;
}

.btn-text {
    background: none;
    color: var(--accent-color);
    padding: 0.5rem;
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

/* Install Prompt */
.install-prompt {
    position: fixed;
    bottom: 1rem;
    left: 50%;
    transform: translateX(-50%);
    background: white;
    padding: 1rem;
    border-radius: 10px;
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: 1rem;
    max-width: 400px;
    width: 90%;
}

/* App Screen */
.app-screen {
    display: flex;
    flex-direction: column;
}

/* App Header */
.app-header {
    background: white;
    padding: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.page-title {
    font-size: 1.25rem;
    font-weight: 600;
}

.icon-btn {
    background: none;
    border: none;
    font-size: 1.25rem;
    color: var(--dark-color);
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 50%;
    position: relative;
}

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

.badge {
    position: absolute;
    top: -5px;
    right: -5px;
    background-color: var(--danger-color);
    color: white;
    font-size: 0.75rem;
    padding: 0.25rem 0.5rem;
    border-radius: 50%;
    min-width: 20px;
    text-align: center;
}

.avatar-btn {
    background: none;
    border: none;
    cursor: pointer;
    padding: 0;
}

.avatar-btn img {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 2px solid var(--border-color);
}

/* Side Menu */
.side-menu {
    background-color: #ffffff !important;
    color: var(--dark-color) !important;
    opacity: 1 !important;
}

.side-menu.active {
    left: 0;
}

.menu-header {
    padding: 2rem 1.5rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    text-align: center;
}

.menu-header img {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    border: 3px solid white;
    margin-bottom: 1rem;
}

.menu-items {
    flex: 1;
    padding: 1rem 0;
    overflow-y: auto;
}

.menu-item {
    padding: 1rem 1.5rem;
    display: flex;
    align-items: center;
    gap: 1rem;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
}

.menu-item:hover {
    background-color: var(--border-color);
}

.menu-item.active {
    background-color: rgba(49, 130, 206, 0.1);
    color: var(--accent-color);
    border-right: 4px solid var(--accent-color);
}

.chat-badge {
    position: absolute;
    right: 1.5rem;
    background-color: var(--danger-color);
    color: white;
    font-size: 0.75rem;
    padding: 0.25rem 0.5rem;
    border-radius: 50%;
    min-width: 20px;
    text-align: center;
}

.menu-footer {
    padding: 1rem 1.5rem;
    border-top: 1px solid var(--border-color);
}

.connection-status {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--success-color);
    font-size: 0.875rem;
    margin-top: 0.5rem;
}

/* Main Content */
.main-content {
    flex: 1;
    padding: 1rem;
    overflow-y: auto;
    padding-bottom: 4rem;
}

.page {
    display: none;
}

.page.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* Cards */
.card {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    margin-bottom: 1rem;
    box-shadow: var(--shadow);
}

.welcome-card {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    margin-bottom: 1.5rem;
}

.welcome-card h2 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.next-session {
    background: white;
    border-left: 5px solid var(--accent-color);
}

.session-details h4 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
}

.session-details p {
    margin-bottom: 0.5rem;
    color: var(--gray-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

/* Quick Stats */
.quick-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
    gap: 1rem;
    margin: 1.5rem 0;
}

.stat-card {
    background: white;
    padding: 1rem;
    border-radius: 10px;
    text-align: center;
    box-shadow: var(--shadow);
}

.stat-card i {
    font-size: 2rem;
    color: var(--accent-color);
    margin-bottom: 0.5rem;
}

.stat-card h4 {
    font-size: 0.875rem;
    color: var(--gray-color);
    margin-bottom: 0.5rem;
}

.stat-card p {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--dark-color);
}

/* Activity List */
.activity-list {
    list-style: none;
}

.activity-list li {
    padding: 0.75rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: 1rem;
}

.activity-list li:last-child {
    border-bottom: none;
}

/* Timetable */
.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.week-selector {
    padding: 0.5rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    background: white;
    font-size: 1rem;
}

.days-nav {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
    overflow-x: auto;
}

.day-btn {
    padding: 0.5rem 1rem;
    border: 2px solid var(--border-color);
    background: white;
    border-radius: 10px;
    cursor: pointer;
    white-space: nowrap;
}

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

.day-schedule {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    box-shadow: var(--shadow);
}

.session-item {
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.session-item:last-child {
    border-bottom: none;
}

.session-time {
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 0.25rem;
}

.session-topic {
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
}

.session-location {
    color: var(--gray-color);
    font-size: 0.875rem;
}

.download-card {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    color: white;
    border-radius: 15px;
    padding: 1.5rem;
    margin-top: 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* Chat */
.chat-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.chat-container {
    display: flex;
    gap: 1rem;
    height: 70vh;
}

.channels-sidebar {
    width: 200px;
    background: white;
    border-radius: 15px;
    padding: 1rem;
    box-shadow: var(--shadow);
}

.channel {
    padding: 0.75rem;
    border-radius: 10px;
    cursor: pointer;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.channel.active {
    background-color: rgba(49, 130, 206, 0.1);
    color: var(--accent-color);
}

.unread-indicator {
    margin-left: auto;
    background-color: var(--danger-color);
    color: white;
    font-size: 0.75rem;
    padding: 0.25rem 0.5rem;
    border-radius: 50%;
    min-width: 20px;
    text-align: center;
}

.chat-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: white;
    border-radius: 15px;
    box-shadow: var(--shadow);
    overflow: hidden;
}

.chat-messages {
    flex: 1;
    padding: 1rem;
    overflow-y: auto;
}

.message {
    margin-bottom: 1rem;
    max-width: 70%;
}

.message.sent {
    margin-left: auto;
}

.message-content {
    background-color: var(--border-color);
    padding: 0.75rem 1rem;
    border-radius: 15px;
    display: inline-block;
}

.message.sent .message-content {
    background-color: var(--accent-color);
    color: white;
}

.message-info {
    font-size: 0.75rem;
    color: var(--gray-color);
    margin-top: 0.25rem;
}

.chat-input {
    padding: 1rem;
    border-top: 1px solid var(--border-color);
    display: flex;
    gap: 0.5rem;
}

.chat-input input {
    flex: 1;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    font-size: 1rem;
}

/* Members Grid */
.search-box {
    position: relative;
    width: 250px;
}

.search-box input {
    width: 100%;
    padding: 0.75rem 1rem 0.75rem 2.5rem;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    font-size: 1rem;
}

.search-box i {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--gray-color);
}

.members-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1rem;
    margin-top: 1.5rem;
}

.member-card {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    text-align: center;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.member-card:hover {
    transform: translateY(-5px);
}

.member-avatar {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    margin: 0 auto 1rem;
    border: 3px solid var(--border-color);
}

.member-name {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.member-phone {
    color: var(--gray-color);
    font-size: 0.875rem;
    margin-bottom: 1rem;
}

.member-actions {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
}

/* Notifications */
.notifications-list {
    background: white;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: var(--shadow);
}

.notification-item {
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: flex-start;
    gap: 1rem;
}

.notification-item.unread {
    background-color: rgba(49, 130, 206, 0.05);
}

.notification-icon {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.notification-content {
    flex: 1;
}

.notification-time {
    font-size: 0.75rem;
    color: var(--gray-color);
    margin-top: 0.25rem;
}

/* Admin Panel */
.admin-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.admin-card {
    background: white;
    border-radius: 15px;
    padding: 2rem;
    text-align: center;
    box-shadow: var(--shadow);
    cursor: pointer;
    transition: var(--transition);
}

.admin-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.admin-card i {
    font-size: 3rem;
    color: var(--accent-color);
    margin-bottom: 1rem;
}

.admin-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

.admin-card p {
    color: var(--gray-color);
    font-size: 0.875rem;
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 2000;
}

.modal-content {
    background: white;
    border-radius: 20px;
    width: 90%;
    max-width: 500px;
    max-height: 90vh;
    overflow-y: auto;
}

.modal-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.close-modal {
    background: none;
    border: none;
    font-size: 2rem;
    cursor: pointer;
    color: var(--gray-color);
}

.modal-body {
    padding: 1.5rem;
}

.profile-avatar {
    text-align: center;
    margin-bottom: 2rem;
}

.profile-avatar img {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    border: 5px solid var(--border-color);
    margin-bottom: 1rem;
}

.profile-info {
    margin-bottom: 2rem;
}

.info-item {
    margin-bottom: 1rem;
}

.info-item label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 500;
    margin-bottom: 0.25rem;
    color: var(--dark-color);
}

.info-item p {
    padding-left: 1.75rem;
    font-size: 1.125rem;
}

.profile-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

/* Responsive Design */
@media (max-width: 768px) {
    .chat-container {
        flex-direction: column;
        height: auto;
    }
    
    .channels-sidebar {
        width: 100%;
        display: flex;
        overflow-x: auto;
        gap: 0.5rem;
    }
    
    .channel {
        white-space: nowrap;
    }
    
    .quick-stats {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .members-grid {
        grid-template-columns: 1fr;
    }
    
    .admin-cards {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .auth-container {
        padding: 1.5rem;
    }
    
    .quick-stats {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .page-header {
        flex-direction: column;
        gap: 1rem;
        align-items: flex-start;
    }
    
    .search-box {
        width: 100%;
    }
}

/* Dark Mode Support */
@media (prefers-color-scheme: dark) {
    :root {
        --light-color: #1a202c;
        --dark-color: #f7fafc;
        --border-color: #4a5568;
        --gray-color: #a0aec0;
    }
    
    body {
        background-color: var(--light-color);
        color: var(--dark-color);
    }
    
    .card, .stat-card, .session-details,
    .day-schedule, .channels-sidebar,
    .chat-main, .member-card,
    .notifications-list, .admin-card {
        background-color: #2d3748;
        color: var(--dark-color);
    }
    
    .input-group input,
    .search-box input,
    .chat-input input,
    .week-selector {
        background-color: #4a5568;
        border-color: #718096;
        color: var(--dark-color);
    }
    
    .message-content {
        background-color: #4a5568;
    }
}

/* Offline Indicator */
.offline-indicator {
    position: fixed;
    bottom: 1rem;
    right: 1rem;
    background-color: var(--warning-color);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    z-index: 1000;
    animation: slideUp 0.3s ease;
}

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