:root {
    /* Color Palette - Premium Dark Theme */
    --bg-color: #0f172a;
    --sidebar-bg: rgba(30, 41, 59, 0.7);
    --board-bg: #0f172a;
    --column-bg: rgba(30, 41, 59, 0.5);
    --card-bg: rgba(51, 65, 85, 0.8);
    --card-hover: rgba(71, 85, 105, 0.9);
    
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --border-color: rgba(255, 255, 255, 0.08);
    
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --accent: #ec4899;
    
    --priority-high: #ef4444;
    --priority-high-bg: rgba(239, 68, 68, 0.15);
    --priority-medium: #f59e0b;
    --priority-medium-bg: rgba(245, 158, 11, 0.15);
    --priority-low: #10b981;
    --priority-low-bg: rgba(16, 185, 129, 0.15);
    
    /* Effects */
    --glass-blur: 12px;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.2);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -1px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -2px rgba(0, 0, 0, 0.2);
    
    --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    overflow: hidden; 
    height: 100vh;
}

/* Layout */
.app-container {
    display: flex;
    height: 100vh;
}

/* Sidebar */
.sidebar {
    width: 260px;
    background: var(--sidebar-bg);
    backdrop-filter: blur(var(--glass-blur));
    -webkit-backdrop-filter: blur(var(--glass-blur));
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    padding: 1.5rem;
    z-index: 10;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 2.5rem;
}

.logo-icon {
    width: 32px;
    height: 32px;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    border-radius: 8px;
    box-shadow: 0 0 15px rgba(99, 102, 241, 0.4);
}

.logo h2 {
    font-size: 1.25rem;
    font-weight: 700;
    letter-spacing: -0.025em;
    background: linear-gradient(to right, #fff, #cbd5e1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-menu {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    flex: 1;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    color: var(--text-muted);
    text-decoration: none;
    border-radius: 8px;
    transition: var(--transition);
    font-weight: 500;
}

.nav-item:hover {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-main);
}

.nav-item.active {
    background: rgba(99, 102, 241, 0.15);
    color: var(--primary);
    border-left: 3px solid var(--primary);
}

/* Main Content */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    background: radial-gradient(circle at top right, rgba(99, 102, 241, 0.08), transparent 40%),
                radial-gradient(circle at bottom left, rgba(236, 72, 153, 0.05), transparent 40%);
}

.top-header {
    height: 70px;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    background: rgba(15, 23, 42, 0.6);
    backdrop-filter: blur(var(--glass-blur));
    z-index: 5;
}

.top-header h1 {
    font-size: 1.5rem;
    font-weight: 600;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.search-bar {
    position: relative;
    display: flex;
    align-items: center;
}

.search-bar svg {
    position: absolute;
    left: 12px;
    color: var(--text-muted);
}

.search-bar input {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    color: var(--text-main);
    padding: 0.5rem 1rem 0.5rem 2.5rem;
    border-radius: 20px;
    outline: none;
    transition: var(--transition);
    width: 240px;
    font-family: inherit;
}

.search-bar input:focus {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--primary);
    box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.2);
}

.avatar {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--accent), #f43f5e);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    cursor: pointer;
    box-shadow: 0 2px 10px rgba(236, 72, 153, 0.3);
}

/* Kanban Board */
.board-container {
    flex: 1;
    overflow-x: auto;
    overflow-y: hidden;
    padding: 1.5rem 2rem;
}

.kanban-board {
    display: flex;
    gap: 1.5rem;
    height: 100%;
    align-items: flex-start;
}

.kanban-column {
    flex: 0 0 320px;
    background: var(--column-bg);
    border-radius: 12px;
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    height: calc(100vh - 120px);
    backdrop-filter: blur(4px);
}

.column-header {
    padding: 1rem 1.25rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    font-weight: 600;
}

.column-title-container {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.task-count {
    background: rgba(255, 255, 255, 0.1);
    padding: 0.15rem 0.5rem;
    border-radius: 12px;
    font-size: 0.75rem;
    color: var(--text-muted);
}

.task-list {
    flex: 1;
    padding: 1rem;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

/* Scrollbar styling */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}
::-webkit-scrollbar-track {
    background: transparent;
}
::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 10px;
}
::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.2);
}

/* Kanban Cards */
.task-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 1.25rem;
    cursor: grab;
    transition: transform 0.2s, box-shadow 0.2s, background-color 0.2s;
    box-shadow: var(--shadow-sm);
    position: relative;
}

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

.task-card:active {
    cursor: grabbing;
}

/* Dragging state */
.sortable-ghost {
    opacity: 0.4;
    background: rgba(99, 102, 241, 0.1);
    border: 2px dashed var(--primary);
}

.task-category {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
    display: block;
}

.task-title {
    font-weight: 500;
    font-size: 0.95rem;
    margin-bottom: 0.5rem;
    line-height: 1.4;
}

.task-desc {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 1rem;
    line-height: 1.5;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* Dependencies Badge */
.task-dependencies {
    margin-top: 0.5rem;
    margin-bottom: 0.5rem;
    font-size: 0.75rem;
    padding: 0.4rem;
    border-radius: 6px;
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid var(--border-color);
}

.task-dependencies strong {
    color: var(--text-main);
}

.dep-item {
    display: flex;
    align-items: center;
    gap: 0.3rem;
    margin-top: 0.2rem;
}

.dep-status {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    display: inline-block;
}

.dep-done { background: var(--priority-low); }
.dep-pending { background: var(--priority-high); }

.task-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-top: 1px solid var(--border-color);
    padding-top: 0.75rem;
    margin-top: 0.5rem;
}

.priority-badge {
    font-size: 0.75rem;
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    font-weight: 500;
}

.priority-high { color: var(--priority-high); background: var(--priority-high-bg); }
.priority-medium { color: var(--priority-medium); background: var(--priority-medium-bg); }
.priority-low { color: var(--priority-low); background: var(--priority-low-bg); }

.task-assignee {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.8rem;
    color: var(--text-muted);
}

.assignee-avatar {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: #475569;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.7rem;
    color: #fff;
}

.delete-btn {
    position: absolute;
    top: 10px;
    right: 10px;
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    opacity: 0;
    transition: var(--transition);
}

.task-card:hover .delete-btn {
    opacity: 1;
}

.delete-btn:hover {
    color: var(--priority-high);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.6rem 1.2rem;
    border-radius: 8px;
    font-weight: 500;
    font-size: 0.9rem;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    font-family: inherit;
}

.w-full { width: 100%; }

.btn-primary {
    background: var(--primary);
    color: white;
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover {
    background: var(--primary-hover);
    box-shadow: 0 6px 16px rgba(99, 102, 241, 0.4);
    transform: translateY(-1px);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-main);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.15);
}

.btn-icon {
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: 0.25rem;
    border-radius: 4px;
    transition: var(--transition);
}

.btn-icon:hover {
    color: var(--text-main);
    background: rgba(255, 255, 255, 0.1);
}

/* Modal */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(15, 23, 42, 0.85);
    backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    opacity: 1;
    transition: opacity 0.3s ease;
}

.modal-overlay.hidden {
    opacity: 0;
    pointer-events: none;
}

.modal-content {
    background: var(--board-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    width: 100%;
    max-width: 500px;
    box-shadow: var(--shadow-lg);
    transform: scale(1);
    transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.modal-overlay.hidden .modal-content {
    transform: scale(0.95);
}

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

.modal-header h2 {
    font-size: 1.25rem;
    font-weight: 600;
}

.modal-body {
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

/* User Grid (Login) */
.user-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
}

.user-btn {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1rem;
    color: var(--text-main);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.75rem;
}

.user-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--primary);
    transform: translateY(-2px);
}

/* Toggle Switch */
.switch {
  position: relative;
  display: inline-block;
  width: 40px;
  height: 22px;
}

.switch input { 
  opacity: 0;
  width: 0;
  height: 0;
}

.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(255,255,255,0.2);
  transition: .4s;
}

.slider:before {
  position: absolute;
  content: "";
  height: 16px;
  width: 16px;
  left: 3px;
  bottom: 3px;
  background-color: white;
  transition: .4s;
}

input:checked + .slider {
  background-color: var(--primary);
}

input:focus + .slider {
  box-shadow: 0 0 1px var(--primary);
}

input:checked + .slider:before {
  transform: translateX(18px);
}

.slider.round {
  border-radius: 22px;
}

.slider.round:before {
  border-radius: 50%;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    flex: 1;
}

.form-row {
    display: flex;
    gap: 1rem;
}

label {
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-muted);
}

input[type="text"], textarea, select {
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 0.75rem;
    color: var(--text-main);
    font-family: inherit;
    font-size: 0.95rem;
    outline: none;
    transition: var(--transition);
}

input[type="text"]:focus, textarea:focus, select:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.2);
}

textarea {
    resize: vertical;
}

select {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%2394a3b8' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 0.75rem center;
    padding-right: 2.5rem;
}

select option {
    background: var(--bg-color);
    color: var(--text-main);
}

.modal-footer {
    padding: 1.5rem;
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: flex-end;
    gap: 1rem;
}