/* Custom CSS variables for themes */
:root {
    --bg-color-light: #f3f4f6; /* Light gray background */
    --text-color-light: #1f2937; /* Dark gray text */
    --card-bg-light: #ffffff; /* White card background */
    --border-color-light: #e5e7eb; /* Light border */
    --primary-color-light: #3b82f6; /* Blue accent */
    --primary-hover-light: #2563eb; /* Darker blue on hover */
    --shadow-color-light: rgba(0, 0, 0, 0.1); /* Soft shadow */
    --input-bg-light: #f9fafb; /* Light input background */

    --bg-color-dark: #1f2937; /* Dark gray background */
    --text-color-dark: #f3f4f6; /* Light gray text */
    --card-bg-dark: #374151; /* Darker gray card background */
    --border-color-dark: #4b5563; /* Dark border */
    --primary-color-dark: #60a5fa; /* Lighter blue accent */
    --primary-hover-dark: #3b82f6; /* Blue on hover */
    --shadow-color-dark: rgba(0, 0, 0, 0.3); /* Darker shadow */
    --input-bg-dark: #4b5563; /* Dark input background */

    /* Default to light theme */
    --bg-color: var(--bg-color-light);
    --text-color: var(--text-color-light);
    --card-bg: var(--card-bg-light);
    --border-color: var(--border-color-light);
    --primary-color: var(--primary-color-light);
    --primary-hover: var(--primary-hover-light);
    --shadow-color: var(--shadow-color-light);
    --input-bg: var(--input-bg-light);
}

/* Dark mode styles */
body.dark-mode {
    --bg-color: var(--bg-color-dark);
    --text-color: var(--text-color-dark);
    --card-bg: var(--card-bg-dark);
    --border-color: var(--border-color-dark);
    --primary-color: var(--primary-color-dark);
    --primary-hover: var(--primary-hover-dark);
    --shadow-color: var(--shadow-color-dark);
    --input-bg: var(--input-bg-dark);
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s ease, color 0.3s ease;
    display: flex;
    min-height: 100vh;
    overflow-x: hidden; /* Prevent horizontal scroll */
}

/* Main layout container */
.container-wrapper {
    display: flex;
    flex-grow: 1;
    width: 100%;
}

/* Sidebar navigation */
.sidebar {
    width: 280px;
    background-color: var(--card-bg);
    border-right: 1px solid var(--border-color);
    padding: 1.5rem;
    box-shadow: 0 4px 12px var(--shadow-color);
    transition: background-color 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
    flex-shrink: 0;
    position: sticky;
    top: 0;
    height: 100vh; /* Full height */
    overflow-y: auto; /* Scrollable if content overflows */
}

.sidebar-header {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 2rem;
    color: var(--primary-color);
}

.nav-link {
    display: block;
    padding: 0.75rem 1rem;
    margin-bottom: 0.5rem;
    border-radius: 0.5rem;
    color: var(--text-color);
    text-decoration: none;
    transition: background-color 0.2s ease, color 0.2s ease, transform 0.1s ease;
    font-weight: 500;
}

.nav-link:hover {
    background-color: var(--primary-color);
    color: white;
    transform: translateX(5px);
}

.nav-link.active {
    background-color: var(--primary-color);
    color: white;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

/* Main content area */
.content-area {
    flex-grow: 1;
    padding: 2rem;
    overflow-y: auto;
    position: relative;
}

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

.page-title {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-color);
}

/* Theme toggle switch */
.theme-toggle {
    position: relative;
    display: inline-block;
    width: 60px;
    height: 34px;
}

.theme-toggle input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--border-color);
    transition: 0.4s;
    border-radius: 34px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 5px; /* Adjust padding to make space for icons */
}

.slider:before { /* This is the draggable circle */
    position: absolute;
    content: "";
    height: 26px;
    width: 26px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: 0.4s;
    border-radius: 50%;
    z-index: 2; /* Ensure slider is above icons */
}

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

input:checked + .slider:before {
    transform: translateX(26px);
}

/* Icon styling */
.sun-icon, .moon-icon {
    font-size: 1.1rem; /* Adjust size as needed */
    position: absolute; /* Position absolutely within the slider */
    transition: opacity 0.4s ease, transform 0.4s ease;
    z-index: 1; /* Ensure icons are below the slider circle but above slider background */
    pointer-events: none; /* Icons should not interfere with slider click */
}

.sun-icon {
    color: #f39c12; /* Sun color */
    left: 8px; /* Position on the left */
    opacity: 1; /* Visible in light mode */
    transform: translateX(0);
}

.moon-icon {
    color: #f1c40f; /* Moon color */
    right: 8px; /* Position on the right */
    opacity: 0; /* Hidden in light mode */
    transform: translateX(0);
}

/* When checked (dark mode) */
body.dark-mode .sun-icon { /* Target based on body class for theme */
    opacity: 0; /* Hide sun */
    transform: translateX(-10px); /* Slide out slightly */
}

body.dark-mode .moon-icon { /* Target based on body class for theme */
    opacity: 1; /* Show moon */
    transform: translateX(0); /* Slide in */
}

/* Calculator card styles */
.calculator-section {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: 0 4px 12px var(--shadow-color);
    transition: background-color 0.3s ease, box-shadow 0.3s ease, opacity 0.5s ease, transform 0.5s ease;
    opacity: 0; /* Hidden by default for transitions */
    transform: translateY(20px); /* Slide in effect */
    /* Removed fixed top/left/width from base class to allow active sections to flow naturally */
    position: absolute; /* Still absolute when hidden for overlapping effect */
    width: calc(100% - 4rem); /* Maintain width for absolute positioning */
    top: 10rem; /* Keep for absolute positioning of hidden elements */
    left: 2rem; /* Keep for absolute positioning of hidden elements */
    pointer-events: none; /* Disable clicks when inactive */
    z-index: 0; /* Ensure inactive sections are behind */
}

.calculator-section.active {
    opacity: 1;
    transform: translateY(0);
    position: relative; /* Active section takes up space in flow */
    top: auto; /* Override the absolute top, let it flow naturally */
    left: auto; /* Override the absolute left, let it flow naturally */
    width: 100%; /* Ensure it takes full width in relative flow */
    pointer-events: auto; /* Enable clicks when active */
    z-index: 1; /* Bring active section to front */
}

.calculator-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.75rem;
}

.calculator-display {
    grid-column: span 4;
    background-color: var(--input-bg);
    color: var(--text-color);
    font-size: 2.5rem;
    padding: 1rem;
    border-radius: 0.5rem;
    text-align: right;
    margin-bottom: 1rem;
    min-height: 60px;
    display: flex;
    align-items: center;
    justify-content: flex-end;
    overflow-x: auto;
}

.calculator-button {
    background-color: var(--border-color);
    color: var(--text-color);
    padding: 1.25rem;
    border-radius: 0.5rem;
    font-size: 1.5rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s ease, transform 0.1s ease, box-shadow 0.2s ease;
    box-shadow: 0 2px 4px var(--shadow-color);
    display: flex;
    align-items: center;
    justify-content: center;
}

.calculator-button:hover {
    background-color: var(--primary-color);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px var(--shadow-color);
}

.calculator-button:active {
    transform: translateY(0);
    box-shadow: 0 1px 2px var(--shadow-color);
}

.calculator-button.operator {
    background-color: var(--primary-color);
    color: white;
}

.calculator-button.operator:hover {
    background-color: var(--primary-hover);
}

.calculator-button.clear, .calculator-button.equals {
    background-color: #ef4444; /* Red for clear */
    color: white;
}

.calculator-button.equals {
    background-color: #10b981; /* Green for equals */
}

.calculator-button.clear:hover {
    background-color: #dc2626;
}

.calculator-button.equals:hover {
    background-color: #059669;
}

/* General form elements */
.input-group {
    margin-bottom: 1.5rem;
}

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

.input-group input[type="number"],
.input-group input[type="date"],
.input-group select,
.history-list {
    width: 100%;
    padding: 0.75rem;
    border-radius: 0.5rem;
    border: 1px solid var(--border-color);
    background-color: var(--input-bg);
    color: var(--text-color); /* Default text color from theme */
    font-size: 1rem;
    transition: border-color 0.2s ease, background-color 0.2s ease;
    box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.05);
}

.input-group input[type="number"]:focus,
.input-group input[type="date"]:focus,
.input-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}

/* Specific style for Numeral System Converter input in dark mode */
body.dark-mode #numeral-value {
    color: #1f2937; /* Dark gray, effectively black on dark background */
}

.result-display {
    margin-top: 1.5rem;
    padding: 1rem;
    background-color: var(--input-bg);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--primary-color);
    min-height: 50px;
    display: flex;
    align-items: center;
    justify-content: flex-start;
    word-break: break-all;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s ease, transform 0.1s ease, box-shadow 0.2s ease;
    box-shadow: 0 2px 4px var(--shadow-color);
    border: none;
}

.btn-primary.danger {
    background-color: #ef4444;
}

.btn-primary.danger:hover {
    background-color: #dc2626;
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px var(--shadow-color);
}

.btn-primary:active {
    transform: translateY(0);
    box-shadow: 0 1px 2px var(--shadow-color);
}

.history-list {
    list-style: none;
    padding: 0;
    max-height: 400px;
    overflow-y: auto;
}

.history-item {
    padding: 0.5rem 1rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 1rem;
    color: var(--text-color);
    transition: background-color 0.2s ease;
}

.history-item:hover {
    background-color: var(--input-bg);
}

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

.history-item .delete-btn {
    background: none;
    border: none;
    color: #ef4444;
    cursor: pointer;
    font-size: 1rem;
    padding: 0.25rem;
    transition: color 0.2s ease;
}

.history-item .delete-btn:hover {
    color: #dc2626;
}


/* Responsive adjustments */
@media (max-width: 768px) {
    .container-wrapper {
    flex-direction: column;
}

.sidebar {
    width: 100%;
    height: auto;
    position: sticky;
    top: 0;
    border-right: none;
    border-bottom: 1px solid var(--border-color);
    padding: 0.5rem;
    box-shadow: none;
    z-index: 10;
    }

.sidebar-header {
    display: none;
    }

.sidebar nav {
display: flex;
overflow-x: auto;
overflow-y: hidden;
white-space: nowrap;
-webkit-overflow-scrolling: touch;
padding-bottom: 0.5rem;
-ms-overflow-style: none;
scrollbar-width: none;
}

.sidebar nav::-webkit-scrollbar {
display: none;
}

.nav-link {
flex-shrink: 0;
padding: 0.5rem 0.75rem;
margin-right: 0.5rem;
font-size: 0.9rem;
}

.content-area {
padding: 1rem;
overflow-y: auto;
flex-grow: 1;
}

.header-bar {
flex-direction: row;
align-items: center;
justify-content: space-between;
margin-bottom: 1rem;
padding-bottom: 0.5rem;
}

.page-title {
margin-bottom: 0;
font-size: 1.5rem;
}

.theme-toggle {
align-self: center;
}

.calculator-section {
padding: 1.5rem;
width: 100%;
left: 0;
top: auto;
}

.calculator-grid {
grid-template-columns: repeat(3, 1fr);
}

.calculator-button {
font-size: 1.2rem;
padding: 1rem;
}

.calculator-display {
font-size: 2rem;
grid-column: span 3;
}
}

@media (max-width: 480px) {
.calculator-grid {
grid-template-columns: repeat(2, 1fr);

.calculator-display {
font-size: 1.8rem;
grid-column: span 2;
}

.calculator-button {
font-size: 1rem;
padding: 0.75rem;
}

.nav-link {
font-size: 0.8rem;
}
}
}