/**
 * ============================================================================
 * NCERT CALCULATOR CSS STYLES
 * ============================================================================
 * 
 * This file styles the calculator components following UI/UX best practices:
 * - WCAG 2.1 AA accessibility standards
 * - Mobile-first responsive design
 * - Touch-friendly interface (min 44x44px targets)
 * - Clear visual hierarchy and feedback
 * - Semantic HTML and keyboard navigation
 * ============================================================================
 */

/* Calculator Container - Fluid Layout with Relative Units */
.ncert-calculator-container {
    max-width: 56.25rem; /* 900px in rem */
    margin: 2rem auto;
    padding: clamp(1rem, 4vw, 2rem); /* Responsive padding */
    background: #ffffff;
    border-radius: 0.5rem;
    box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
    /* Ensure proper contrast for accessibility */
    color: #212529;
}

/* Calculator Wrapper */
.calculator-wrapper {
    width: 100%;
}

/* Calculator Header */
.calculator-header {
    border-bottom: 2px solid #e9ecef;
    padding-bottom: 1rem;
}

.calculator-title {
    font-size: clamp(1.5rem, 4vw, 1.75rem); /* Responsive typography */
    font-weight: 600;
    color: #212529;
    margin-bottom: 0.5rem;
    line-height: 1.3; /* Improved readability */
}

.calculator-description {
    font-size: clamp(0.9rem, 2.5vw, 1rem); /* Responsive typography */
    color: #6c757d;
    margin-bottom: 0;
    line-height: 1.6; /* Improved readability */
}

/* Formula Display */
.calculator-formula {
    background: #f8f9fa;
    border-left: 4px solid #0d6efd;
    padding: 1rem;
    border-radius: 0.25rem;
}

.calculator-formula code {
    font-size: 1.1rem;
    color: #0d6efd;
    background: transparent;
    padding: 0;
}

/* Calculator Form */
.calculator-form {
    margin-top: 1.5rem;
}

.calculator-form-inner {
    width: 100%;
}

/* Input/Output Groups - Omni Calculator Style (Card-based) */
.calculator-input-group,
.calculator-output-group {
    background: #ffffff;
    border: 1px solid #e0e0e0;
    border-radius: 0.5rem;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.calculator-group-header {
    margin-bottom: 1rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid #f0f0f0;
}

.calculator-group-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: #212529;
    margin: 0;
    text-transform: none;
    letter-spacing: normal;
}

.calculator-group-fields {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 12.5rem), 1fr)); /* Responsive grid with rem units */
    gap: clamp(0.75rem, 2vw, 1rem); /* Responsive gap with minimum spacing */
    /* Ensure adequate spacing for touch targets */
    align-items: start;
}

.calculator-group-field {
    margin-bottom: 0;
}

.calculator-field-label {
    font-size: clamp(0.875rem, 2vw, 0.9375rem); /* Responsive typography */
    font-weight: 600; /* Increased weight for better hierarchy */
    color: #212529; /* Darker for better contrast (WCAG AA) */
    margin-bottom: 0.5rem;
    display: block;
    line-height: 1.5;
    /* Ensure labels are associated with inputs for screen readers */
    cursor: pointer;
}

.calculator-input-wrapper {
    position: relative;
}

/* Input Fields Section (Legacy - for backward compatibility) */
.calculator-inputs h4,
.calculator-outputs h4 {
    font-size: 1.25rem;
    font-weight: 600;
    color: #212529;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid #dee2e6;
}

/* Input Fields - Touch-Friendly and Accessible */
.calculator-input {
    font-size: clamp(1rem, 2.5vw, 1.125rem); /* Responsive font size */
    padding: clamp(0.75rem, 2vw, 1rem) clamp(1rem, 3vw, 1.25rem); /* Responsive padding */
    min-height: 2.75rem; /* 44px minimum for touch targets */
    border: 2px solid #ced4da; /* Increased border for better visibility */
    border-radius: 0.5rem; /* Slightly larger radius for modern look */
    transition: all 0.2s ease-in-out; /* Smooth transitions */
    width: 100%;
    background: #ffffff;
    /* Ensure proper contrast (WCAG AA) */
    color: #212529;
    line-height: 1.5;
}

.calculator-input:hover {
    border-color: #adb5bd;
    background-color: #f8f9fa;
}

.calculator-group-field .calculator-input {
    background: #fafafa;
}

.calculator-input:focus {
    border-color: #0d6efd;
    outline: 2px solid transparent; /* Remove default outline */
    outline-offset: 2px;
    box-shadow: 0 0 0 0.25rem rgba(13, 110, 253, 0.25);
    background-color: #ffffff;
}

/* Focus visible for keyboard navigation */
.calculator-input:focus-visible {
    outline: 2px solid #0d6efd;
    outline-offset: 2px;
}

/* Error States - Clear Visual Feedback */
.calculator-input.is-invalid {
    border-color: #dc3545;
    background-color: #fff5f5; /* Light red background for visibility */
}

.calculator-input.is-invalid:focus {
    border-color: #dc3545;
    box-shadow: 0 0 0 0.25rem rgba(220, 53, 69, 0.25);
    background-color: #fff5f5;
}

/* Error message styling */
.calculator-error-message {
    color: #dc3545;
    font-size: 0.875rem;
    margin-top: 0.25rem;
    display: block;
    font-weight: 500;
}

/* Success state for valid inputs */
.calculator-input.is-valid {
    border-color: #198754;
    background-color: #f0f9f4; /* Light green background */
}

.calculator-input.is-valid:focus {
    border-color: #198754;
    box-shadow: 0 0 0 0.25rem rgba(25, 135, 84, 0.25);
}

/* Output Fields (Results) - Accessible and Clear */
.calculator-output {
    font-size: clamp(1rem, 2.5vw, 1.125rem); /* Responsive typography */
    font-weight: 600;
    padding: clamp(0.75rem, 2vw, 1rem) clamp(1rem, 3vw, 1.25rem); /* Responsive padding */
    min-height: 2.75rem; /* 44px minimum for touch targets */
    background-color: #f8f9fa;
    border: 2px solid #ced4da; /* Increased border for visibility */
    border-radius: 0.5rem;
    color: #212529;
    text-align: left;
    width: 100%;
    transition: all 0.2s ease-in-out;
    line-height: 1.5;
    /* Ensure proper contrast and readability */
    font-family: inherit; /* Use system font for better readability */
}

.calculator-group-field .calculator-output {
    background: #fafafa;
}

.calculator-output:not(:placeholder-shown) {
    background-color: #e7f3ff;
    border-color: #0d6efd;
    color: #0d6efd;
}

.calculator-output:focus {
    border-color: #0a58ca;
    outline: 0;
    box-shadow: 0 0 0 0.25rem rgba(13, 110, 253, 0.25);
}

.calculator-output.is-invalid {
    border-color: #dc3545;
    color: #dc3545;
}

/* Calculator Actions (Buttons) - Omni Calculator Style */
.calculator-actions {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
    padding: clamp(1.25rem, 3vw, 1.5rem) 0;
    border-top: 1px solid #dee2e6;
    border-bottom: 1px solid #dee2e6;
    margin: clamp(1.25rem, 3vw, 1.5rem) 0;
}

.calculator-actions-left {
    display: flex;
    gap: 0.75rem;
}

.calculator-actions-right {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.calculate-btn,
.reset-btn {
    min-width: 9.375rem; /* 150px in rem */
    min-height: 2.75rem; /* 44px minimum for touch targets */
    padding: clamp(0.75rem, 2vw, 0.875rem) clamp(1.25rem, 3vw, 1.5rem); /* Responsive padding */
    font-size: clamp(0.9375rem, 2.5vw, 1rem); /* Responsive typography */
    font-weight: 600;
    border-radius: 0.5rem;
    transition: all 0.2s ease-in-out; /* Smooth transitions */
    cursor: pointer;
    border: 2px solid transparent; /* Consistent border width */
    /* Ensure keyboard accessibility */
    position: relative;
}

/* Focus states for keyboard navigation */
.calculate-btn:focus-visible,
.reset-btn:focus-visible {
    outline: 2px solid currentColor;
    outline-offset: 2px;
}

/* Button Icons */
.btn-icon {
    display: inline-block;
    margin-right: 0.375rem;
    font-weight: bold;
}

.calculate-btn {
    background-color: #0d6efd;
    border-color: #0d6efd;
    color: #ffffff;
}

.calculate-btn:hover {
    background-color: #0b5ed7;
    border-color: #0a58ca;
    transform: translateY(-1px);
    box-shadow: 0 0.25rem 0.5rem rgba(0, 0, 0, 0.1);
}

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

/* Secondary Action Buttons (Share, Reload, Clear) */
.share-result-btn,
.reload-calculator-btn,
.clear-changes-btn {
    background-color: #ffffff;
    border: 1px solid #dee2e6;
    color: #495057;
    font-size: 0.875rem;
    padding: 0.5rem 0.75rem;
    min-height: 2.25rem; /* Slightly smaller than main button */
}

.share-result-btn:hover,
.reload-calculator-btn:hover {
    background-color: #f8f9fa;
    border-color: #adb5bd;
    color: #212529;
}

.clear-changes-btn:disabled,
.clear-changes-btn.disabled {
    opacity: 0.5;
    cursor: not-allowed;
    background-color: #f8f9fa;
    color: #6c757d;
}

.clear-changes-btn:not(:disabled):hover {
    background-color: #f8f9fa;
    border-color: #adb5bd;
    color: #212529;
}

/* Loading State - Clear User Feedback */
.calculator-loading {
    padding: clamp(2rem, 5vw, 3rem);
    text-align: center;
    min-height: 10rem; /* Prevent layout shift */
}

.calculator-loading .spinner-border {
    width: 3rem;
    height: 3rem;
    border-width: 0.25rem;
}

/* Loading text for screen readers */
.calculator-loading .visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

/* Result Display */
.calculator-result {
    position: relative;
}

.calculator-result::before {
    content: '=';
    position: absolute;
    left: -2rem;
    top: 50%;
    transform: translateY(-50%);
    font-size: 1.5rem;
    font-weight: bold;
    color: #0d6efd;
}

/* Responsive Design - Mobile-First Approach */
/* Base styles are mobile-first, these are enhancements for larger screens */

/* Small devices (landscape phones, 576px and up) */
@media (min-width: 36rem) {
    .calculator-group-fields {
        grid-template-columns: repeat(auto-fit, minmax(min(100%, 12.5rem), 1fr));
    }
}

/* Medium devices (tablets, 768px and up) */
@media (min-width: 48rem) {
    .calculator-group-fields {
        grid-template-columns: repeat(auto-fit, minmax(12.5rem, 1fr));
    }
}

/* Mobile-specific adjustments (below 768px) */
@media (max-width: 47.9375rem) {
    .ncert-calculator-container {
        margin: 1rem;
        padding: clamp(1rem, 3vw, 1.5rem);
    }

    .calculator-title {
        font-size: clamp(1.25rem, 5vw, 1.5rem);
    }

    .calculator-actions {
        flex-direction: column;
        gap: 1rem;
    }

    .calculator-actions-left,
    .calculator-actions-right {
        width: 100%;
        flex-direction: column;
    }

    .calculate-btn {
        width: 100%;
        min-height: 3rem; /* Larger touch target on mobile */
    }

    .share-result-btn,
    .reload-calculator-btn,
    .clear-changes-btn {
        width: 100%;
        min-height: 2.75rem;
    }

    .calculator-feedback-buttons {
        flex-direction: column;
    }

    .feedback-btn {
        width: 100%;
    }

    .calculator-result::before {
        display: none;
    }

    .calculator-group-fields {
        grid-template-columns: 1fr; /* Single column on mobile */
        gap: 1rem; /* Adequate spacing */
    }

    .calculator-input-group,
    .calculator-output-group {
        padding: clamp(1rem, 3vw, 1.25rem);
    }

    /* Ensure touch targets are adequate on mobile */
    .calculator-input,
    .calculator-output {
        min-height: 3rem; /* Larger on mobile for easier tapping */
        font-size: 1rem; /* Prevent zoom on iOS */
    }
}

/* Form Label Styling */
.calculator-form-inner .form-label {
    font-weight: 600;
    color: #495057;
    margin-bottom: 0.5rem;
}

/* Success State (when calculation is successful) */
.calculator-output:not(.is-invalid):not(:placeholder-shown) {
    background-color: #d1e7dd;
    border-color: #198754;
    color: #198754;
}

/* Animation for results - Subtle and Accessible */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-0.5rem);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.calculator-output:not(:placeholder-shown) {
    animation: fadeIn 0.3s ease-in-out;
}

/* Respect user's motion preferences */
@media (prefers-reduced-motion: reduce) {
    .calculator-output:not(:placeholder-shown),
    .calculator-input,
    .calculator-output,
    .calculate-btn,
    .reset-btn {
        animation: none;
        transition: none;
    }
}

/* Article Content Styles */
.ncert-calculator-page-wrapper {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

.ncert-calculator-article-content {
    margin-top: 3rem;
    padding-top: 3rem;
    border-top: 2px solid #e9ecef;
}

/* Table of Contents */
.calculator-toc {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 0.5rem;
    margin-bottom: 2rem;
}

.calculator-toc h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: #212529;
    margin-bottom: 1rem;
}

.calculator-toc ul {
    margin: 0;
    padding-left: 1.5rem;
}

.calculator-toc li {
    margin-bottom: 0.5rem;
}

.calculator-toc a {
    color: #0d6efd;
    transition: color 0.15s ease-in-out;
}

.calculator-toc a:hover {
    color: #0a58ca;
    text-decoration: underline;
}

/* Article Sections */
.calculator-article-sections {
    line-height: 1.8;
    width: 100%;
    max-width: 100%;
    overflow-wrap: break-word;
    word-wrap: break-word;
}

.calculator-section {
    margin-bottom: clamp(2rem, 4vw, 3rem);
    padding-bottom: clamp(1.5rem, 3vw, 2rem);
    border-bottom: 1px solid #e9ecef;
    width: 100%;
    max-width: 100%;
    overflow-wrap: break-word;
    word-wrap: break-word;
}

.calculator-section:last-child {
    border-bottom: none;
}

.calculator-section-title {
    font-weight: 600;
    color: #212529;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid #0d6efd;
    word-wrap: break-word;
    overflow-wrap: break-word;
    hyphens: auto;
    line-height: 1.4;
}

.calculator-section-title.h2 {
    font-size: clamp(1.5rem, 3vw, 1.75rem);
}

.calculator-section-title.h3 {
    font-size: clamp(1.25rem, 2.5vw, 1.5rem);
    border-bottom: 1px solid #dee2e6;
}

.calculator-section-title.h4 {
    font-size: clamp(1.1rem, 2vw, 1.25rem);
    border-bottom: 1px solid #e9ecef;
}

.calculator-section-content {
    color: #495057;
    font-size: clamp(1rem, 1.5vw, 1.125rem);
    line-height: 1.7;
    width: 100%;
    max-width: 100%;
    overflow-wrap: break-word;
    word-wrap: break-word;
}

.calculator-section-content p {
    margin-bottom: 1rem;
}

.calculator-section-content ul,
.calculator-section-content ol {
    margin-bottom: 1rem;
    padding-left: 2rem;
}

.calculator-section-content code {
    background: #f8f9fa;
    padding: 0.2rem 0.4rem;
    border-radius: 0.25rem;
    font-size: 0.9em;
    color: #d63384;
}

.calculator-section-content pre {
    background: #f8f9fa;
    padding: 1rem;
    border-radius: 0.5rem;
    overflow-x: auto;
    margin-bottom: 1rem;
}

.calculator-section-content pre code {
    background: transparent;
    padding: 0;
    color: #212529;
}

/* Feedback Section - Omni Calculator Style */
.calculator-feedback {
    padding: 1.5rem 0;
    border-top: 1px solid #e9ecef;
    text-align: center;
}

.calculator-feedback-question {
    font-size: 1rem;
    color: #495057;
    margin-bottom: 1rem;
    font-weight: 500;
}

.calculator-feedback-buttons {
    display: flex;
    gap: 0.75rem;
    justify-content: center;
    flex-wrap: wrap;
}

.feedback-btn {
    min-width: 5rem;
    min-height: 2.5rem;
    font-size: 0.9375rem;
    padding: 0.5rem 1rem;
    border-width: 1px;
}

.feedback-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.feedback-yes {
    border-color: #198754;
    color: #198754;
}

.feedback-yes:hover:not(:disabled) {
    background-color: #198754;
    color: #ffffff;
}

.feedback-no {
    border-color: #dc3545;
    color: #dc3545;
}

.feedback-no:hover:not(:disabled) {
    background-color: #dc3545;
    color: #ffffff;
}

/* Print Styles */
@media print {
    .ncert-calculator-container {
        box-shadow: none;
        border: 1px solid #dee2e6;
    }

    .calculator-actions,
    .calculator-feedback {
        display: none;
    }
    
    .calculator-toc {
        page-break-after: always;
    }
}

/* Responsive adjustments for article content */
@media (max-width: 768px) {
    .ncert-calculator-page-wrapper {
        padding: 1rem 0.5rem;
    }
    
    .calculator-section-title.h2 {
        font-size: clamp(1.25rem, 2.5vw, 1.5rem);
    }
    
    .calculator-section-title.h3 {
        font-size: clamp(1.1rem, 2vw, 1.25rem);
    }
    
    .calculator-section-title.h4 {
        font-size: clamp(1rem, 1.5vw, 1.1rem);
    }
    
    .calculator-toc {
        padding: clamp(0.75rem, 2vw, 1rem);
    }
    
    .calculator-section {
        margin-bottom: clamp(1.5rem, 3vw, 2rem);
        padding-bottom: clamp(1rem, 2vw, 1.5rem);
    }
    
    .calculator-section-content {
        font-size: clamp(0.9375rem, 1.5vw, 1rem);
    }
}