/* ============================================
   CSS Variables & Theme System
   ============================================ */
:root {
    /* Light Theme Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-tertiary: #f0f2f5;
    --text-primary: #1a1a2e;
    --text-secondary: #6c757d;
    --text-tertiary: #adb5bd;
    
    /* Accent Colors */
    --accent-primary: #667eea;
    --accent-secondary: #764ba2;
    --accent-blue: #3498db;
    --accent-green: #27ae60;
    --accent-red: #e74c3c;
    --accent-orange: #f39c12;
    --accent-gray: #95a5a6;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-blue: linear-gradient(135deg, #3498db 0%, #2980b9 100%);
    --gradient-green: linear-gradient(135deg, #27ae60 0%, #229954 100%);
    --gradient-card: linear-gradient(135deg, rgba(102, 126, 234, 0.1) 0%, rgba(118, 75, 162, 0.1) 100%);
    
    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.15);
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.2);
    
    /* Borders */
    --border-color: #e0e0e0;
    --border-radius: 12px;
    --border-radius-sm: 8px;
    
    /* Navbar */
    --navbar-bg: linear-gradient(135deg, #2c3e50 0%, #34495e 100%);
    --navbar-text: #ffffff;
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

[data-theme="dark"] {
    /* Dark Theme Colors */
    --bg-primary: #1a1a2e;
    --bg-secondary: #16213e;
    --bg-tertiary: #0f1419;
    --text-primary: #e4e6eb;
    --text-secondary: #b0b3b8;
    --text-tertiary: #8a8d91;
    
    /* Accent Colors (lighter for dark theme) */
    --accent-primary: #7c8ef5;
    --accent-secondary: #9b6dd4;
    --accent-blue: #5dade2;
    --accent-green: #52c41a;
    --accent-red: #ff6b6b;
    --accent-orange: #ffa726;
    --accent-gray: #b0b3b8;
    
    /* Gradients (adjusted for dark theme) */
    --gradient-primary: linear-gradient(135deg, #7c8ef5 0%, #9b6dd4 100%);
    --gradient-blue: linear-gradient(135deg, #5dade2 0%, #3498db 100%);
    --gradient-green: linear-gradient(135deg, #52c41a 0%, #27ae60 100%);
    --gradient-card: linear-gradient(135deg, rgba(124, 142, 245, 0.15) 0%, rgba(155, 109, 212, 0.15) 100%);
    
    /* Shadows (softer for dark theme) */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.5);
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.6);
    
    /* Borders */
    --border-color: #2d3748;
    
    /* Navbar */
    --navbar-bg: linear-gradient(135deg, #0f1419 0%, #1a1a2e 100%);
    --navbar-text: #e4e6eb;
}

/* ============================================
   Global Styles
   ============================================ */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-secondary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

main.container {
    flex: 1;
    width: 100%;
}

/* ============================================
   Navbar
   ============================================ */
.navbar {
    background: var(--navbar-bg);
    color: var(--navbar-text);
    padding: 1.25rem 0;
    box-shadow: var(--shadow-md);
    position: sticky;
    top: 0;
    z-index: 100;
    transition: background var(--transition-normal), box-shadow var(--transition-normal);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--navbar-text);
    text-decoration: none;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    transition: transform var(--transition-fast);
}

.logo:hover {
    transform: scale(1.05);
}

.nav-links {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.nav-links a {
    color: var(--navbar-text);
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius-sm);
    transition: all var(--transition-fast);
    position: relative;
}

.nav-links a:hover {
    background: rgba(255, 255, 255, 0.1);
    transform: translateY(-1px);
}

/* Theme Toggle Button */
#theme-toggle {
    background: rgba(255, 255, 255, 0.1);
    border: none;
    border-radius: var(--border-radius-sm);
    padding: 0.5rem 0.75rem;
    cursor: pointer;
    font-size: 1.25rem;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 40px;
    height: 40px;
}

#theme-toggle:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: scale(1.1);
}

.theme-icon {
    display: block;
}

/* ============================================
   Buttons
   ============================================ */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    transition: all var(--transition-normal);
    text-decoration: none;
    display: inline-block;
    text-align: center;
    box-shadow: var(--shadow-sm);
}

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

.btn:active {
    transform: translateY(0);
}

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

.btn-primary:hover {
    background: var(--gradient-blue);
    filter: brightness(1.1);
}

.btn-success {
    background: var(--gradient-green);
    color: white;
}

.btn-success:hover {
    background: var(--gradient-green);
    filter: brightness(1.1);
}

.btn-danger {
    background: var(--accent-red);
    color: white;
}

.btn-danger:hover {
    background: var(--accent-red);
    filter: brightness(1.1);
}

.btn-secondary {
    background: var(--accent-gray);
    color: white;
}

.btn-secondary:hover {
    background: var(--accent-gray);
    filter: brightness(1.1);
}

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

/* ============================================
   Login Page
   ============================================ */
.login-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: var(--gradient-primary);
    position: relative;
    overflow: hidden;
}

.login-container::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255,255,255,0.1) 1px, transparent 1px);
    background-size: 50px 50px;
    animation: moveBackground 20s linear infinite;
}

@keyframes moveBackground {
    0% { transform: translate(0, 0); }
    100% { transform: translate(50px, 50px); }
}

.login-box {
    background: var(--bg-primary);
    padding: 2.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-xl);
    text-align: center;
    min-width: 350px;
    position: relative;
    z-index: 1;
    transition: background var(--transition-normal), box-shadow var(--transition-normal);
}

.login-theme-toggle {
    position: absolute;
    top: 1rem;
    right: 1rem;
}

.login-box #theme-toggle {
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--border-radius-sm);
    padding: 0.5rem 0.75rem;
    cursor: pointer;
    font-size: 1.25rem;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 40px;
    height: 40px;
}

.login-box #theme-toggle:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: scale(1.1) rotate(15deg);
}

.login-box h1 {
    margin-bottom: 0.5rem;
    color: var(--text-primary);
    font-size: 2rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.login-box p {
    margin-bottom: 1.5rem;
    color: var(--text-secondary);
    font-size: 1rem;
}

.error-message {
    background: linear-gradient(135deg, rgba(231, 76, 60, 0.1) 0%, rgba(192, 57, 43, 0.1) 100%);
    color: var(--accent-red);
    padding: 1rem;
    border-radius: var(--border-radius-sm);
    margin-bottom: 1rem;
    border: 1px solid rgba(231, 76, 60, 0.3);
}

.whitelist-error-message {
    background: linear-gradient(135deg, rgba(255, 193, 7, 0.1) 0%, rgba(255, 152, 0, 0.1) 100%);
    color: var(--accent-orange);
    padding: 1.5rem;
    border: 1px solid rgba(255, 193, 7, 0.3);
    border-radius: var(--border-radius);
    margin-top: 1.5rem;
    text-align: center;
}

.whitelist-error-message h3 {
    margin-top: 0;
    margin-bottom: 1rem;
    color: var(--accent-orange);
    font-size: 1.25rem;
}

.whitelist-error-message p {
    margin-bottom: 0.75rem;
    line-height: 1.6;
    color: var(--text-secondary);
}

.whitelist-error-message p:last-of-type {
    margin-bottom: 1rem;
}

#telegram-login-container {
    margin-top: 1rem;
}

/* ============================================
   Dashboard
   ============================================ */
.dashboard {
    padding: 2.5rem 0;
    width: 100%;
}

.dashboard h1 {
    margin-bottom: 2rem;
    color: var(--text-primary);
    font-size: 2.5rem;
    font-weight: 700;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
    width: 100%;
}

.stat-card {
    background: var(--bg-primary);
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--gradient-primary);
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.stat-card h3 {
    margin-bottom: 1rem;
    color: var(--text-primary);
    font-size: 1.1rem;
    font-weight: 600;
}

.stat-card .count {
    font-size: 2.5rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.5rem;
}

.stat-card .sub-count {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.quick-actions {
    background: var(--bg-primary);
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    transition: background var(--transition-normal), box-shadow var(--transition-normal);
}

.quick-actions h2 {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    font-size: 1.5rem;
    font-weight: 600;
}

.action-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

/* ============================================
   Tasks/Reminders Pages
   ============================================ */
.tasks-page, .reminders-page {
    padding: 2.5rem 0;
}

.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.page-header h1 {
    color: var(--text-primary);
    font-size: 2.5rem;
    font-weight: 700;
}

.filters {
    display: flex;
    gap: 0.75rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 0.625rem 1.25rem;
    border: 2px solid var(--border-color);
    background: var(--bg-primary);
    color: var(--text-primary);
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    transition: all var(--transition-normal);
    font-weight: 500;
}

.filter-btn:hover {
    background: var(--bg-secondary);
    border-color: var(--accent-primary);
    transform: translateY(-1px);
}

.filter-btn.active {
    background: var(--gradient-primary);
    color: white;
    border-color: transparent;
    box-shadow: var(--shadow-sm);
}

.tasks-list, .reminders-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.task-card, .reminder-card {
    background: var(--bg-primary);
    padding: 1.75rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-normal);
    border: 1px solid var(--border-color);
}

.task-card:hover, .reminder-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--accent-primary);
}

.task-card.completed {
    opacity: 0.6;
    background: var(--bg-secondary);
}

.task-header, .reminder-header {
    display: flex;
    justify-content: space-between;
    align-items: start;
    margin-bottom: 1rem;
    gap: 1rem;
}

.task-header h3, .reminder-header h3 {
    color: var(--text-primary);
    flex: 1;
    font-size: 1.25rem;
    font-weight: 600;
}

.task-actions, .reminder-actions {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.task-description, .reminder-description {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    line-height: 1.6;
}

.task-meta, .reminder-meta {
    display: flex;
    gap: 1.5rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
    flex-wrap: wrap;
}

.task-priority, .reminder-recurrence {
    font-weight: 600;
    color: var(--accent-primary);
}

.task-status, .reminder-status {
    padding: 0.375rem 0.75rem;
    border-radius: var(--border-radius-sm);
    background: var(--bg-secondary);
    color: var(--text-primary);
    font-weight: 500;
    font-size: 0.875rem;
}

/* ============================================
   Kanban Board
   ============================================ */
.kanban-board {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
    margin-top: 2rem;
}

.kanban-column {
    background: var(--bg-secondary);
    border-radius: var(--border-radius);
    padding: 1.25rem;
    min-height: 500px;
    border: 2px solid var(--border-color);
    transition: all var(--transition-normal);
}

.kanban-column.drag-over {
    border-color: var(--accent-primary);
    background: var(--bg-tertiary);
    box-shadow: 0 0 20px rgba(102, 126, 234, 0.3);
}

.kanban-column-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.25rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid var(--border-color);
}

.kanban-column-header h2 {
    color: var(--text-primary);
    font-size: 1.5rem;
    font-weight: 700;
    margin: 0;
}

.task-count {
    background: var(--accent-primary);
    color: white;
    padding: 0.375rem 0.75rem;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 600;
    min-width: 2rem;
    text-align: center;
}

.kanban-column-content {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    min-height: 400px;
}

.kanban-card {
    background: var(--bg-primary);
    padding: 1.25rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    cursor: grab;
    transition: all var(--transition-normal);
    position: relative;
}

.kanban-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
    border-color: var(--accent-primary);
}

.kanban-card.dragging {
    opacity: 0.5;
    cursor: grabbing;
    transform: rotate(2deg);
    box-shadow: var(--shadow-xl);
}

.kanban-card.completed {
    opacity: 0.7;
    background: var(--bg-secondary);
}

.kanban-card-header {
    margin-bottom: 0.75rem;
}

.kanban-card-header h3 {
    color: var(--text-primary);
    font-size: 1.125rem;
    font-weight: 600;
    margin: 0;
    word-wrap: break-word;
}

.kanban-card-description {
    color: var(--text-secondary);
    font-size: 0.875rem;
    line-height: 1.5;
    margin-bottom: 0.75rem;
    word-wrap: break-word;
}

.kanban-card-meta {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    font-size: 0.8125rem;
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
}

.kanban-card-due-date {
    color: var(--accent-orange);
    font-weight: 500;
}

.kanban-card-priority {
    color: var(--accent-primary);
    font-weight: 600;
}

.kanban-card-actions {
    display: flex;
    gap: 0.5rem;
    margin-top: 0.75rem;
    padding-top: 0.75rem;
    border-top: 1px solid var(--border-color);
}

.empty-message, .loading-message {
    text-align: center;
    color: var(--text-tertiary);
    padding: 2rem;
    font-style: italic;
}

/* Responsive Kanban Board */
@media (max-width: 1024px) {
    .kanban-board {
        grid-template-columns: 1fr;
    }
    
    .kanban-column {
        min-height: 300px;
    }
}

@media (max-width: 768px) {
    .kanban-board {
        gap: 1rem;
    }
    
    .kanban-column {
        padding: 1rem;
        min-height: 250px;
    }
    
    .kanban-column-header h2 {
        font-size: 1.25rem;
    }
}

/* ============================================
   Modal
   ============================================ */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.6);
    overflow: auto;
    backdrop-filter: blur(4px);
    animation: fadeIn var(--transition-normal);
}

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

.modal-content {
    background: var(--bg-primary);
    margin: 5% auto;
    padding: 2.5rem;
    border-radius: var(--border-radius);
    width: 90%;
    max-width: 500px;
    position: relative;
    box-shadow: var(--shadow-xl);
    animation: slideDown var(--transition-normal);
    transition: background var(--transition-normal);
}

@keyframes slideDown {
    from {
        transform: translateY(-50px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.close {
    position: absolute;
    right: 1.5rem;
    top: 1.5rem;
    font-size: 2rem;
    font-weight: bold;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
}

.close:hover {
    color: var(--text-primary);
    background: var(--bg-secondary);
    transform: rotate(90deg);
}

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

.form-group label {
    display: block;
    margin-bottom: 0.75rem;
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.95rem;
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 0.875rem;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    font-size: 1rem;
    background: var(--bg-primary);
    color: var(--text-primary);
    transition: all var(--transition-fast);
    font-family: inherit;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

.form-actions {
    display: flex;
    gap: 1rem;
    justify-content: flex-end;
    margin-top: 2rem;
}

/* ============================================
   Footer
   ============================================ */
footer {
    background: var(--navbar-bg);
    color: var(--navbar-text);
    padding: 1.5rem 0;
    margin-top: auto;
    text-align: center;
    transition: background var(--transition-normal);
}

footer p {
    margin: 0;
    opacity: 0.9;
}

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 768px) {
    .navbar .container {
        flex-wrap: wrap;
    }
    
    .nav-links {
        flex-direction: row;
        gap: 1rem;
        flex-wrap: wrap;
    }
    
    .page-header {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .task-header, .reminder-header {
        flex-direction: column;
    }
    
    .task-actions, .reminder-actions {
        width: 100%;
        justify-content: flex-start;
    }
    
    .login-box {
        min-width: auto;
        width: 90%;
        padding: 2rem 1.5rem;
    }
    
    .modal-content {
        padding: 2rem 1.5rem;
        width: 95%;
    }
}

@media (max-width: 480px) {
    .dashboard h1,
    .page-header h1 {
        font-size: 2rem;
    }
    
    .action-buttons {
        flex-direction: column;
    }
    
    .action-buttons .btn {
        width: 100%;
    }
}