:root {
    /* Human-Made Palette - Light Mode */
    --paper-bg: #fdfbf7;
    --paper-line: #aeb6bf;
    /* Light blue/grey for lines */
    --ink-color: #2c3e50;
    --pencil-color: #7f8c8d;

    /* Semantic Backgrounds */
    --surface-color: #ffffff;
    --sidebar-bg: #f5f0e1;
    /* Manila folder color */
    --input-bg: #ffffff;
    --btn-secondary-bg: #ffffff;
    --task-item-bg: #ffffff;

    /* Accents (Highlighter style) */
    --primary-color: #ff6b6b;
    /* Marker Red */
    --primary-hover: #ee5253;
    --secondary-color: #54a0ff;
    /* Blue Pen */
    --success-color: #1dd1a1;
    /* Green Highligher */
    --warning-color: #feca57;
    /* Yellow Highlighter */
    --danger-color: #ff6b6b;

    /* Text */
    --text-primary: #2c3e50;
    /* Ink */
    --text-secondary: #7f8c8d;
    /* Pencil */

    /* Borders */
    --border-color: #2c3e50;
    --border-width: 2px;
    --border-radius-sketch: 255px 15px 225px 15px / 15px 225px 15px 255px;

    /* Layout */
    --sidebar-width: 260px;
    --shadow-sketch: 4px 4px 0px rgba(44, 62, 80, 0.2);
}

[data-theme="dark"] {
    /* Blackboard / Dark Construction Paper Theme */
    --paper-bg: #2b2b2b;
    /* Dark Slate */
    --surface-color: #3d3d3d;
    /* Dark Grey Card */
    --sidebar-bg: #333333;
    /* Slightly lighter spiral binder */
    --input-bg: #4a4a4a;
    /* Input fields */
    --btn-secondary-bg: #3d3d3d;
    --task-item-bg: #3d3d3d;

    --text-primary: #f0f0f0;
    /* Chalk White */
    --text-secondary: #aaaaaa;
    /* Light Grey Chalk */
    --border-color: #f0f0f0;
    /* White Chalk Outline */
    --paper-line: #444444;
    /* Dark line */
    --ink-color: #f0f0f0;

    --shadow-sketch: 4px 4px 0px rgba(0, 0, 0, 0.5);
}

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

body {
    font-family: 'Patrick Hand', cursive;
    background-color: var(--paper-bg);
    color: var(--text-primary);
    line-height: 1.6;
    height: 100vh;
    overflow: hidden;
    background-image: radial-gradient(var(--paper-line) 1px, transparent 1px);
    background-size: 20px 20px;
    /* Dot grid paper effect */
    font-size: 1.1rem;
}

/* App Layout */
.app-container {
    display: flex;
    height: 100vh;
    padding: 10px;
    gap: 10px;
}

/* Sidebar - "Notebook Spiral" or "Sticky Note" style */
.sidebar {
    width: var(--sidebar-width);
    background-color: var(--sidebar-bg);
    border: var(--border-width) solid var(--border-color);
    border-radius: var(--border-radius-sketch);
    display: flex;
    flex-direction: column;
    padding: 1.5rem;
    box-shadow: var(--shadow-sketch);
    transform: rotate(-1deg);
    z-index: 10;
}

.logo h1 {
    font-family: 'Permanent Marker', cursive;
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 2rem;
    text-align: center;
    transform: rotate(-2deg);
}

.main-nav ul {
    list-style: none;
}

.main-nav li {
    padding: 0.75rem 1rem;
    margin-bottom: 0.8rem;
    border: var(--border-width) solid transparent;
    /* Invisible border for layout stability */
    border-radius: 20px 5px 20px 5px;
    cursor: pointer;
    font-weight: 500;
    color: var(--text-primary);
    transition: all 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.2rem;
}

.main-nav li:hover {
    transform: scale(1.05) rotate(1deg);
    background-color: rgba(0, 0, 0, 0.05);
}

.main-nav li.active {
    background-color: var(--surface-color);
    border: var(--border-width) solid var(--border-color);
    box-shadow: 3px 3px 0 rgba(0, 0, 0, 0.1);
    transform: scale(1.05) rotate(-1deg);
    font-weight: bold;
}

/* Main Content - "Open Page" */
.main-content {
    flex: 1;
    overflow-y: auto;
    padding: 2rem;
    background-color: var(--surface-color);
    border: var(--border-width) solid var(--border-color);
    border-radius: 5px 20px 5px 20px;
    /* Less sketchy, more page-like */
    box-shadow: var(--shadow-sketch);
    position: relative;
    /* Lined paper effect for main content background */
    background-image: linear-gradient(var(--paper-line) 1px, transparent 1px);
    background-size: 100% 2rem;
    background-attachment: local;
}

/* Headers */
.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding-bottom: 0.5rem;
    border-bottom: 3px solid var(--border-color);
    transform: rotate(0.5deg);
}

.section-header h2 {
    font-family: 'Permanent Marker', cursive;
    font-size: 2.5rem;
    color: var(--text-primary);
}

/* Sections */
.hidden-section {
    display: none;
}

.active-section {
    display: block;
    animation: scribbleIn 0.4s ease-out;
}

@keyframes scribbleIn {
    0% {
        opacity: 0;
        transform: translateY(10px) rotate(-1deg);
    }

    100% {
        opacity: 1;
        transform: translateY(0) rotate(0deg);
    }
}

/* Cards & Grid */
.dashboard-grid,
.card-grid,
.analytics-grid {
    display: grid;
    gap: 1.5rem;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.stat-card,
.dashboard-card,
.chart-container {
    background-color: var(--paper-bg);
    padding: 1.5rem;
    border: var(--border-width) solid var(--border-color);
    border-radius: var(--border-radius-sketch);
    box-shadow: var(--shadow-sketch);
    transition: transform 0.2s;
    /* Sticky note feel */
}

.stat-card:hover,
.dashboard-card:hover {
    transform: translateY(-3px) rotate(1deg);
    box-shadow: 6px 6px 0 rgba(0, 0, 0, 0.15);
}

.stat-card h3 {
    font-family: 'Patrick Hand', cursive;
    font-size: 1.1rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    border-bottom: 1px dashed var(--text-secondary);
    padding-bottom: 5px;
    margin-bottom: 10px;
}

.stat-value {
    font-family: 'Permanent Marker', cursive;
    font-size: 3rem;
    color: var(--primary-color);
}

.full-width {
    grid-column: 1 / -1;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.6rem 1.2rem;
    border-radius: 255px 15px 225px 15px / 15px 225px 15px 255px;
    font-family: 'Patrick Hand', cursive;
    font-weight: 700;
    font-size: 1.1rem;
    cursor: pointer;
    border: var(--border-width) solid var(--border-color);
    transition: all 0.2s;
    box-shadow: 2px 2px 0 var(--border-color);
}

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

.btn-primary:hover {
    transform: translate(-1px, -1px);
    box-shadow: 4px 4px 0 var(--border-color);
}

.btn-primary:active {
    transform: translate(2px, 2px);
    box-shadow: 0 0 0 var(--border-color);
}

.btn-secondary {
    background-color: var(--btn-secondary-bg);
    color: var(--text-primary);
}

.btn-secondary:hover {
    background-color: var(--input-bg);
    /* Slight contrast on hover */
    transform: translate(-1px, -1px);
    box-shadow: 4px 4px 0 var(--border-color);
}

.btn-danger {
    background-color: #ff7675;
    color: white;
}

/* Forms & Inputs */
.form-group {
    margin-bottom: 1.2rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 700;
    font-size: 1.1rem;
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 0.8rem;
    border: var(--border-width) solid var(--border-color);
    border-radius: 10px;
    /* Slightly sketched */
    background-color: var(--input-bg);
    color: var(--text-primary);
    font-family: 'Patrick Hand', cursive;
    font-size: 1.1rem;
    box-shadow: 2px 2px 0 rgba(0, 0, 0, 0.05);
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 4px 4px 0 var(--primary-color);
    transform: scale(1.01);
}

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

.form-row .form-group {
    flex: 1;
}

/* Modals */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.4);
    /* Dimmed background */
    backdrop-filter: blur(3px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.modal {
    background-color: var(--paper-bg);
    padding: 2rem;
    border: var(--border-width) solid var(--border-color);
    border-radius: var(--border-radius-sketch);
    width: 90%;
    max-width: 500px;
    box-shadow: 8px 8px 0 rgba(0, 0, 0, 0.2);
    animation: popUp 0.3s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

@keyframes popUp {
    from {
        transform: scale(0.8) rotate(-5deg);
        opacity: 0;
    }

    to {
        transform: scale(1) rotate(0deg);
        opacity: 1;
    }
}

.modal.hidden,
.modal-overlay.hidden {
    display: none;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    border-bottom: 2px dashed var(--border-color);
    padding-bottom: 10px;
}

.modal-header h3 {
    font-family: 'Permanent Marker', cursive;
    font-size: 1.5rem;
}

.close-modal {
    background: none;
    border: none;
    font-size: 2rem;
    cursor: pointer;
    color: var(--danger-color);
    font-family: 'Permanent Marker', cursive;
}

.close-modal:hover {
    transform: rotate(90deg);
}

/* Task Filters */
.task-filters {
    margin-bottom: 1.5rem;
    display: flex;
    gap: 0.8rem;
    overflow-x: auto;
    padding-bottom: 0.5rem;
}

.filter-btn {
    background: none;
    border: var(--border-width) solid var(--border-color);
    padding: 0.5rem 1.2rem;
    border-radius: 255px 15px 225px 15px / 15px 225px 15px 255px;
    cursor: pointer;
    font-family: 'Patrick Hand', cursive;
    font-size: 1rem;
    font-weight: bold;
    color: var(--text-primary);
    transition: all 0.2s;
}

.filter-btn.active,
.filter-btn:hover {
    background-color: var(--primary-color);
    color: white;
    box-shadow: 3px 3px 0 var(--border-color);
    transform: rotate(-2deg);
}

/* Task List Item */
.task-item {
    background-color: var(--task-item-bg);
    padding: 1rem;
    border: var(--border-width) solid var(--border-color);
    border-radius: 5px;
    /* Post-it style */
    margin-bottom: 0.75rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: 2px 2px 0 rgba(0, 0, 0, 0.05);
    transition: transform 0.2s;
}

.task-item:hover {
    transform: scale(1.02);
}

.task-item.completed {
    opacity: 0.7;
    text-decoration: line-through;
    background-color: rgba(0, 0, 0, 0.1);
    /* Darken slightly instead of hardcoded grey */
    border-style: dashed;
}

.task-item.overdue {
    border-left: 6px solid var(--danger-color);
    background-color: rgba(255, 107, 107, 0.1);
    /* Light red tint */
}

/* Priority Tags */
.priority-tag {
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.85rem;
    font-weight: bold;
    text-transform: capitalize;
}

.priority-high {
    background-color: #ff7675;
    color: white;
}

.priority-medium {
    background-color: #ffeaa7;
    color: #d35400;
}

.priority-low {
    background-color: #55efc4;
    color: #00b894;
}

/* Switch (Theme Toggle) - "Doodle Switch" */
.switch {
    position: relative;
    display: inline-block;
    width: 60px;
    height: 30px;
}

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

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #ccc;
    border: 2px solid var(--border-color);
    border-radius: 20px;
    transition: .4s;
    box-shadow: inset 2px 2px 5px rgba(0, 0, 0, 0.1);
}

.slider:before {
    position: absolute;
    content: "";
    height: 20px;
    width: 20px;
    left: 3px;
    bottom: 3px;
    background-color: white;
    border: 2px solid var(--border-color);
    transition: .4s;
    border-radius: 50%;
}

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

input:checked+.slider:before {
    transform: translateX(28px);
}


/* Settings Page Layout */
.settings-container {
    display: flex;
    flex-direction: column;
    gap: 2rem;
    max-width: 600px;
    margin-top: 1rem;
}

.setting-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem;
    background-color: var(--paper-bg);
    border: var(--border-width) solid var(--border-color);
    border-radius: 5px;
    box-shadow: 2px 2px 0 rgba(0, 0, 0, 0.05);
    margin-bottom: 2rem;
    /* Extra spacing */
}

.setting-item label {
    font-size: 1.2rem;
    font-weight: bold;
    font-family: 'Permanent Marker', cursive;
}

.setting-actions {
    display: flex;
    gap: 1.5rem;
    padding-top: 1.5rem;
    border-top: 2px dashed var(--border-color);
}

/* Responsive */
@media (max-width: 768px) {
    .app-container {
        flex-direction: column;
        padding: 5px;
        gap: 5px;
    }

    .sidebar {
        width: 100%;
        height: auto;
        padding: 1rem;
        flex-direction: row;
        align-items: center;
        justify-content: space-between;
        overflow-x: auto;
        transform: none;
        /* Reset rotation for mobile */
        border-radius: 10px;
    }

    .logo h1 {
        margin-bottom: 0;
        font-size: 1.5rem;
        transform: none;
    }

    .main-nav ul {
        display: flex;
        gap: 0.5rem;
    }

    .main-nav li {
        margin-bottom: 0;
        padding: 0.5rem;
        font-size: 1.5rem;
        /* Larger icons for touch */
    }

    .main-nav li span:not(.icon) {
        display: none;
    }

    .main-content {
        padding: 1rem;
        zoom: 0.9;
        /* Scale down slightly for mobile */
    }
}