:root {
    /* Custom Portfolio Color Palette */
    --bg-color: #141414;        /* Deep charcoal from portfolio */
    --surface-color: #1c1c1c;   /* Card background */
    --surface-hover: #262626;
    --text-primary: #f2f2f2;
    --text-secondary: #999999;
    
    --accent-color: #4f726e;    /* Sophisticated Sage Green */
    --accent-hover: #405c59;
    
    --success-color: #4f726e;   /* Monochromatic elegance */
    --danger-color: #e57373;
    
    --font-ui: 'Inter', -apple-system, sans-serif;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: var(--font-ui);
    display: flex;
    justify-content: center;
    min-height: 100vh;
    overflow-x: hidden;
}

/* --------------------------------------
   Layout & Containers
   -------------------------------------- */
.app-container {
    width: 100%;
    max-width: 500px;
    display: flex;
    flex-direction: column;
    padding: 2rem 1.5rem;
}

/* --------------------------------------
   Header
   -------------------------------------- */
.header-section {
    position: sticky;
    top: 0;
    background: rgba(20, 20, 20, 0.9);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    z-index: 10;
    padding-bottom: 1rem;
    margin-bottom: 1rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.header-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    gap: 1rem;
}

.header-top h1 {
    font-size: 2.2rem;
    font-weight: 700;
    letter-spacing: -0.5px;
    color: var(--text-primary);
}

.icon-btn {
    background: var(--surface-color);
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: var(--text-primary);
    width: 44px;
    height: 44px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    flex-shrink: 0;
    transition: all 0.2s ease;
}

.icon-btn:hover {
    background: var(--surface-hover);
    transform: scale(1.05);
}

.add-btn {
    background: var(--accent-color);
    border: none;
    transition: background 0.2s ease, transform 0.2s ease;
}

.add-btn:hover {
    background: var(--accent-hover);
    transform: scale(1.05);
}

/* --------------------------------------
   Filter Tabs
   -------------------------------------- */
.filters {
    display: flex;
    gap: 0.5rem;
    background: var(--surface-color);
    padding: 0.3rem;
    border-radius: 16px; /* Smooth curves */
}

.filter-tab {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    padding: 0.6rem 0;
    border-radius: 12px;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.filter-tab.active {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-primary);
    box-shadow: 0 2px 8px rgba(0,0,0,0.2);
}

/* --------------------------------------
   Modal (Add/Edit Task)
   -------------------------------------- */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    display: flex;
    justify-content: center;
    align-items: flex-end;
    z-index: 100;
    opacity: 1;
    transition: opacity 0.3s ease;
}

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

.modal-content {
    background: var(--surface-color);
    width: 100%;
    max-width: 500px;
    border-radius: 28px 28px 0 0;
    padding: 2rem 1.5rem;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    transform: translateY(100%) scale(0.95);
    opacity: 0;
    transition: transform 0.5s cubic-bezier(0.16, 1, 0.3, 1), opacity 0.5s ease;
}

.modal-overlay:not(.hidden) .modal-content {
    transform: translateY(0) scale(1);
    opacity: 1;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    gap: 1rem;
}

.modal-header h2 {
    font-size: 1.5rem;
}

.input-group {
    display: flex;
    flex-direction: column;
    margin-bottom: 1.2rem;
}

.input-group label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    font-weight: 500;
}

/* Native Inputs with Dark Mode UI */
.input-group input {
    color-scheme: dark; /* Forces native calendar/time picker into dark mode! */
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: var(--text-primary);
    padding: 1rem;
    border-radius: 16px; /* Smooth curves */
    font-size: 1rem;
    font-family: var(--font-ui);
    outline: none;
    transition: border-color 0.2s;
    width: 100%;
    box-sizing: border-box;
}

.input-group input:focus {
    border-color: var(--accent-color);
}

.datetime-row {
    display: flex;
    gap: 1rem;
}
.datetime-row .input-group {
    flex: 1;
}

.priority-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 0.5rem;
    margin-bottom: 1.5rem;
    padding: 0.8rem 1rem;
    background: rgba(0, 0, 0, 0.15);
    border-radius: 12px;
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.priority-label {
    display: flex;
    align-items: center;
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--text-primary);
}

/* Switch Toggle Styling */
.switch {
    position: relative;
    display: inline-block;
    width: 44px;
    height: 24px;
}
.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, 0.1);
    transition: .3s;
    border-radius: 24px;
}
.slider:before {
    position: absolute;
    content: "";
    height: 18px;
    width: 18px;
    left: 3px;
    bottom: 3px;
    background-color: var(--text-secondary);
    transition: .3s;
    border-radius: 50%;
}
input:checked + .slider {
    background-color: var(--danger-color);
}
input:checked + .slider:before {
    transform: translateX(20px);
    background-color: #fff;
}

.submit-btn {
    width: 100%;
    padding: 1rem;
    background: var(--accent-color);
    color: #fff;
    border: none;
    border-radius: 16px; /* Smooth curves */
    font-size: 1.05rem;
    font-weight: 600;
    cursor: pointer;
    margin-top: 0.5rem;
    transition: transform 0.1s, background 0.2s;
}

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

.submit-btn:active {
    transform: scale(0.98);
}

/* --------------------------------------
   Task List
   -------------------------------------- */
.task-list-container {
    flex: 1;
    overflow-y: auto;
    padding-bottom: 2rem;
}

.task-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    padding: 5px; /* Prevent hover slice */
}

.task-item {
    background: var(--surface-color);
    border-radius: 20px; /* Smooth curves */
    padding: 1.2rem;
    display: flex;
    align-items: center;
    gap: 1rem;
    border: 1px solid rgba(255, 255, 255, 0.05);
    position: relative;
    overflow: hidden;
    transition: transform 0.2s cubic-bezier(0.16, 1, 0.3, 1), box-shadow 0.2s ease, border-color 0.2s ease, opacity 0.3s ease;
    /* Animation removed from base class to fix flash bug */
}

.task-item:hover {
    transform: translateY(-3px);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.25);
    border-color: rgba(79, 114, 110, 0.5); /* Subtle accent color glow */
}

.task-item.animate-in {
    animation: slideIn 0.3s ease forwards;
}

.task-item.high-priority {
    border: 1px solid rgba(229, 115, 115, 0.3);
    background: linear-gradient(to right, rgba(229, 115, 115, 0.05), var(--surface-color));
}

.task-item.high-priority:hover {
    border-color: var(--danger-color);
    box-shadow: 0 12px 24px rgba(229, 115, 115, 0.15);
}

.task-item.completed {
    opacity: 0.55;
    background: var(--surface-hover);
}

.task-item.completed:hover {
    transform: translateY(0);
    box-shadow: none;
    border-color: rgba(255, 255, 255, 0.05);
}

.task-item.completed .task-title {
    text-decoration: line-through;
    color: var(--text-secondary);
}

/* Custom Checkbox */
.checkbox-container {
    position: relative;
    width: 24px;
    height: 24px;
    flex-shrink: 0;
    cursor: pointer;
}

.checkbox-container input {
    opacity: 0;
    width: 0;
    height: 0;
}

.checkmark {
    position: absolute;
    top: 0;
    left: 0;
    height: 24px;
    width: 24px;
    background-color: transparent;
    border: 2px solid var(--text-secondary);
    border-radius: 50%;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.checkbox-container:hover input ~ .checkmark {
    border-color: var(--accent-color);
}

.checkbox-container input:checked ~ .checkmark {
    background-color: var(--success-color);
    border-color: var(--success-color);
}

.checkmark svg {
    display: none;
    width: 14px;
    height: 14px;
    color: #fff;
}

.checkbox-container input:checked ~ .checkmark svg {
    display: block;
    animation: checkPop 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

/* Task Content */
.task-content {
    flex: 1;
    min-width: 0;
}

.task-title {
    font-size: 1.1rem;
    font-weight: 500;
    margin-bottom: 0.4rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    transition: color 0.2s;
}

.task-meta {
    font-size: 0.85rem;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.task-meta svg {
    width: 14px;
    height: 14px;
}

/* Actions */
.task-actions {
    display: flex;
    gap: 0.2rem;
}

.action-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 10px;
    transition: all 0.2s;
}

.action-btn:hover {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
}

.action-btn.delete:hover {
    color: var(--danger-color);
    background: rgba(229, 115, 115, 0.1);
}

/* Empty State */
.empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 250px;
    color: var(--text-secondary);
    text-align: center;
    gap: 1rem;
    animation: fadeIn 0.5s ease;
}

.empty-state.hidden {
    display: none;
}

/* Animations */
@keyframes slideIn {
    from { opacity: 0; transform: translateY(15px) scale(0.98); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}

@keyframes checkPop {
    0% { transform: scale(0); }
    100% { transform: scale(1); }
}

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

/* Responsive adjust for desktop */
@media (min-width: 768px) {
    .app-container {
        padding-top: 4rem;
    }
    .modal-content {
        border-radius: 28px;
        margin-bottom: 10vh;
    }
    .modal-overlay {
        align-items: center;
    }
}

/* --------------------------------------
   Flatpickr Custom Theme Overrides
   -------------------------------------- */
.flatpickr-calendar {
    background: var(--surface-color) !important;
    border: 1px solid rgba(255, 255, 255, 0.05) !important;
    box-shadow: 0 20px 40px rgba(0,0,0,0.7) !important;
    border-radius: 16px !important;
    font-family: var(--font-ui) !important;
    z-index: 99999 !important; /* Force to float above everything */
    animation: popupAnim 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    overflow: hidden !important;
}

@keyframes popupAnim {
    from { opacity: 0; transform: translateY(-10px) scale(0.95); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}

.flatpickr-months .flatpickr-month,
.flatpickr-current-month .flatpickr-monthDropdown-months,
.flatpickr-current-month input.cur-year {
    background: var(--surface-color) !important;
    color: var(--text-primary) !important;
}

span.flatpickr-weekday {
    color: var(--text-secondary) !important;
    font-weight: 600 !important;
}

.flatpickr-day {
    color: var(--text-primary) !important;
    border-radius: 8px !important;
}

.flatpickr-day:hover {
    background: var(--surface-hover) !important;
    border-color: var(--surface-hover) !important;
}

.flatpickr-day.selected,
.flatpickr-day.startRange,
.flatpickr-day.endRange,
.flatpickr-day.selected.inRange,
.flatpickr-day.startRange.inRange,
.flatpickr-day.endRange.inRange,
.flatpickr-day.selected:focus,
.flatpickr-day.startRange:focus,
.flatpickr-day.endRange:focus,
.flatpickr-day.selected:hover,
.flatpickr-day.startRange:hover,
.flatpickr-day.endRange:hover,
.flatpickr-day.selected.prevMonthDay,
.flatpickr-day.startRange.prevMonthDay,
.flatpickr-day.endRange.prevMonthDay,
.flatpickr-day.selected.nextMonthDay,
.flatpickr-day.startRange.nextMonthDay,
.flatpickr-day.endRange.nextMonthDay {
    background: var(--accent-color) !important;
    border-color: var(--accent-color) !important;
    color: #fff !important;
}

.flatpickr-time {
    border-radius: 16px !important;
    overflow: hidden !important;
}

.flatpickr-time input:hover,
.flatpickr-time .flatpickr-am-pm:hover,
.flatpickr-time input:focus,
.flatpickr-time .flatpickr-am-pm:focus {
    background: var(--surface-hover) !important;
    outline: none !important;
    border: none !important;
    box-shadow: none !important;
}

.flatpickr-time .numInputWrapper {
    border-radius: 12px;
    overflow: hidden;
}

.flatpickr-time .flatpickr-am-pm {
    border-radius: 12px;
    margin: 2px;
}

.flatpickr-time input,
.flatpickr-time .flatpickr-am-pm {
    outline: none !important;
    box-shadow: none !important;
    border-radius: 12px !important;
    -webkit-user-select: none !important;
    user-select: none !important;
}

/* Offset standalone time picker so it doesn't overflow the right edge of modal */
.flatpickr-calendar.hasTime.noCalendar {
    transform: translateX(-15px) !important;
}

.flatpickr-time .numInputWrapper span.arrowDown:after {
    border-top-color: var(--text-secondary) !important;
}
.flatpickr-time .numInputWrapper span:hover.arrowUp:after {
    border-bottom-color: var(--accent-color) !important;
}
.flatpickr-time .numInputWrapper span:hover.arrowDown:after {
    border-top-color: var(--accent-color) !important;
}

/* --------------------------------------
   Toast Notifications
   -------------------------------------- */
.toast-container {
    position: fixed;
    bottom: 20px;
    right: 20px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    z-index: 999999;
}

.toast {
    background: var(--surface-color);
    border: 1px solid var(--accent-color);
    color: var(--text-primary);
    padding: 1rem 1.5rem;
    border-radius: 12px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
    display: flex;
    align-items: center;
    gap: 12px;
    font-family: var(--font-ui);
    animation: slideInToast 0.4s cubic-bezier(0.16, 1, 0.3, 1) forwards;
    cursor: pointer;
}

.toast.fade-out {
    animation: fadeOutToast 0.4s ease forwards;
}

.toast-icon {
    color: var(--accent-color);
    display: flex;
    align-items: center;
    justify-content: center;
}

.toast-content {
    display: flex;
    flex-direction: column;
}

.toast-title {
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-weight: 600;
    margin-bottom: 2px;
}

.toast-message {
    font-size: 1rem;
    font-weight: 500;
}

@keyframes slideInToast {
    from { transform: translateX(120%); opacity: 0; }
    to { transform: translateX(0); opacity: 1; }
}

@keyframes fadeOutToast {
    from { transform: translateX(0); opacity: 1; }
    to { transform: translateX(120%); opacity: 0; }
}