/*
 * Discount Calculator - Custom Styles
 * Dark theme with CSS variables for maintainability
 * Mobile-first responsive design
 * Accessibility focused
 */

:root {
    /* Color Variables */
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --accent: #16a34a;
    --accent-hover: #15803d;
    --warning: #f59e0b;
    --danger: #ef4444;
    --info: #06b6d4;
    --success: #22c55e;
    
    /* Background Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-card: #ffffff;
    --bg-card-hover: #f1f5f9;
    --bg-dark-subtle: rgba(248, 250, 252, 0.8);
    
    /* Text Colors */
    --text-primary: #1e293b;
    --text-secondary: #475569;
    --text-muted: #64748b;
    
    /* Border Colors */
    --border-primary: #e2e8f0;
    --border-secondary: #cbd5e1;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', sans-serif;
    
    /* Spacing */
    --border-radius: 0.5rem;
    --border-radius-lg: 0.75rem;
    
    /* Transitions */
    --transition: all 0.15s ease-in-out;
    --transition-slow: all 0.3s ease-in-out;
}

/* Base Styles */
* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-family);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Custom Bootstrap Overrides */
.bg-dark {
    background-color: var(--bg-primary) !important;
}

.bg-light {
    background-color: var(--bg-primary) !important;
}

.bg-card {
    background-color: var(--bg-card) !important;
    border: 1px solid var(--border-primary) !important;
}

.bg-dark-subtle {
    background-color: var(--bg-dark-subtle) !important;
}

.text-light {
    color: var(--text-primary) !important;
}

.text-dark {
    color: var(--text-primary) !important;
}

.text-muted {
    color: var(--text-muted) !important;
}

.border-secondary {
    border-color: var(--border-secondary) !important;
}

/* Card Enhancements */
.card {
    border-radius: var(--border-radius-lg);
    transition: var(--transition);
}

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

.card-header {
    border-radius: var(--border-radius-lg) var(--border-radius-lg) 0 0;
}

/* Form Controls */
.form-control {
    border-radius: var(--border-radius);
    transition: var(--transition);
    background-color: var(--bg-secondary);
    border-color: var(--border-secondary);
    color: var(--text-primary);
}

.form-control:focus {
    background-color: var(--bg-secondary);
    border-color: var(--primary);
    box-shadow: 0 0 0 0.2rem rgba(37, 99, 235, 0.25);
    color: var(--text-primary);
}

.form-control::placeholder {
    color: var(--text-muted);
    opacity: 0.7;
}

.form-select {
    background-color: var(--bg-secondary);
    border-color: var(--border-secondary);
    color: var(--text-primary);
}

.form-select:focus {
    background-color: var(--bg-secondary);
    border-color: var(--primary);
    box-shadow: 0 0 0 0.2rem rgba(37, 99, 235, 0.25);
    color: var(--text-primary);
}

.form-select option {
    background-color: var(--bg-secondary);
    color: var(--text-primary);
}

.input-group-text {
    background-color: var(--bg-secondary);
    border-color: var(--border-secondary);
    color: var(--text-primary);
}

/* Button Styles */
.btn {
    border-radius: var(--border-radius);
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

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

.btn-primary:hover {
    background-color: var(--primary-hover);
    border-color: var(--primary-hover);
    transform: translateY(-1px);
}

.btn-outline-primary {
    color: var(--primary);
    border-color: var(--primary);
}

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

.btn-outline-secondary {
    color: var(--text-secondary);
    border-color: var(--border-secondary);
}

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

/* Navigation */
.navbar-brand {
    font-weight: 700;
    font-size: 1.25rem;
}

.nav-link {
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

.nav-link:hover {
    color: var(--primary) !important;
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 50%;
    transform: translateX(-50%);
    width: 30px;
    height: 3px;
    background-color: var(--primary);
    border-radius: 2px;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.02'%3E%3Ccircle cx='30' cy='30' r='1'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
    pointer-events: none;
}

.bg-gradient {
    background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
}

/* Results Display */
.results-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-secondary);
    border-radius: var(--border-radius-lg);
    animation: fadeInUp 0.5s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Result Cards */
.result-item {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-primary);
    border-radius: var(--border-radius);
    padding: 1rem;
    text-align: center;
    transition: var(--transition);
}

.result-item:hover {
    background-color: var(--bg-card-hover);
    border-color: var(--border-secondary);
}

.result-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    display: block;
}

.result-label {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

/* Badges */
.badge {
    font-weight: 500;
    border-radius: var(--border-radius);
}

.badge.bg-success {
    background-color: var(--success) !important;
}

.badge.bg-info {
    background-color: var(--info) !important;
}

.badge.bg-warning {
    background-color: var(--warning) !important;
    color: var(--bg-primary) !important;
}

/* Accordion */
.accordion-button {
    background-color: var(--bg-card);
    border-color: var(--border-secondary);
    color: var(--text-primary);
    font-weight: 500;
}

.accordion-button:not(.collapsed) {
    background-color: var(--bg-secondary);
    border-color: var(--primary);
    color: var(--primary);
}

.accordion-button:focus {
    box-shadow: 0 0 0 0.2rem rgba(37, 99, 235, 0.25);
    border-color: var(--primary);
}

.accordion-body {
    background-color: var(--bg-card);
    border-color: var(--border-secondary);
}

/* Footer */
footer {
    margin-top: auto;
    background-color: var(--bg-primary) !important;
    border-top: 1px solid var(--border-secondary) !important;
}

footer a:hover {
    color: var(--primary) !important;
    text-decoration: underline !important;
}

/* Breadcrumb */
.breadcrumb {
    background: transparent;
    padding: 0;
    margin-bottom: 1rem;
}

.breadcrumb-item a {
    color: var(--text-secondary);
    text-decoration: none;
}

.breadcrumb-item a:hover {
    color: var(--primary);
}

.breadcrumb-item.active {
    color: var(--text-muted);
}

/* Toast Notifications */
.toast {
    background-color: var(--bg-card);
    border: 1px solid var(--border-secondary);
    color: var(--text-primary);
}

.toast-header {
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-secondary);
    color: var(--text-primary);
}

/* Loading States */
.btn.loading {
    pointer-events: none;
    opacity: 0.7;
}

.btn.loading::after {
    content: '';
    width: 16px;
    height: 16px;
    border: 2px solid transparent;
    border-top: 2px solid currentColor;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    display: inline-block;
    margin-left: 8px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Focus Styles for Accessibility */
.btn:focus,
.form-control:focus,
.form-select:focus {
    box-shadow: 0 0 0 0.2rem rgba(37, 99, 235, 0.25);
    outline: 2px solid transparent;
}

/* Skip to content link */
.visually-hidden-focusable:focus {
    position: static !important;
    width: auto !important;
    height: auto !important;
}

/* Responsive Tables */
.table-responsive-custom {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.breakdown-table {
    background-color: var(--bg-secondary);
    border-radius: var(--border-radius);
    overflow: hidden;
}

.breakdown-table th {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-weight: 600;
    border-color: var(--border-secondary);
    padding: 0.75rem;
}

.breakdown-table td {
    border-color: var(--border-primary);
    color: var(--text-secondary);
    padding: 0.75rem;
}

.breakdown-table tbody tr:hover {
    background-color: var(--bg-card-hover);
}

/* Sample Buttons */
.sample-btn,
.gst-sample-btn,
.multi-sample-btn,
.coupon-sample-btn {
    font-size: 0.875rem;
    padding: 0.375rem 0.75rem;
    white-space: nowrap;
}

/* Alert Enhancements */
.alert {
    border-radius: var(--border-radius);
    border: 1px solid;
}

.alert-info {
    background-color: rgba(6, 182, 212, 0.1);
    border-color: var(--info);
    color: var(--info);
}

.alert-success {
    background-color: rgba(34, 197, 94, 0.1);
    border-color: var(--success);
    color: var(--success);
}

.alert-warning {
    background-color: rgba(245, 158, 11, 0.1);
    border-color: var(--warning);
    color: var(--warning);
}

.alert-danger {
    background-color: rgba(239, 68, 68, 0.1);
    border-color: var(--danger);
    color: var(--danger);
}

/* Utility Classes */
.text-primary-custom {
    color: var(--primary) !important;
}

.bg-gradient-primary {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-hover) 100%);
}

.border-primary-custom {
    border-color: var(--primary) !important;
}

/* Animation Classes */
.fade-in {
    animation: fadeIn 0.5s ease-in;
}

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

.slide-up {
    animation: slideUp 0.3s ease-out;
}

@keyframes slideUp {
    from {
        transform: translateY(10px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

/* Error States */
.form-control.is-invalid {
    border-color: var(--danger);
    box-shadow: 0 0 0 0.2rem rgba(239, 68, 68, 0.25);
}

.form-select.is-invalid {
    border-color: var(--danger);
    box-shadow: 0 0 0 0.2rem rgba(239, 68, 68, 0.25);
}

.invalid-feedback {
    color: var(--danger);
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

/* Success States */
.form-control.is-valid {
    border-color: var(--success);
    box-shadow: 0 0 0 0.2rem rgba(34, 197, 94, 0.25);
}

.valid-feedback {
    color: var(--success);
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

/* Comparison Highlight */
.better-deal {
    border: 2px solid var(--success) !important;
    box-shadow: 0 0 0 0.1rem rgba(34, 197, 94, 0.1);
}

.better-deal .card-header {
    background-color: rgba(34, 197, 94, 0.1) !important;
}

/* Mobile Optimizations */
@media (max-width: 768px) {
    .display-4 {
        font-size: 2rem;
    }
    
    .display-5 {
        font-size: 1.75rem;
    }
    
    .lead {
        font-size: 1.1rem;
    }
    
    .hero {
        padding: 2rem 0;
    }
    
    .card-body {
        padding: 1.5rem;
    }
    
    .btn {
        width: 100%;
        margin-bottom: 0.5rem;
    }
    
    .btn-group-mobile .btn {
        width: auto;
        margin-bottom: 0;
    }
    
    .result-value {
        font-size: 1.25rem;
    }
    
    /* Stack form elements on mobile */
    .col-md-6 {
        margin-bottom: 1rem;
    }
}

@media (max-width: 576px) {
    .container {
        padding-left: 1rem;
        padding-right: 1rem;
    }
    
    .display-4 {
        font-size: 1.75rem;
        line-height: 1.2;
    }
    
    .hero {
        text-align: center;
    }
    
    .badge {
        font-size: 0.75rem;
        margin: 0.25rem;
    }
}

/* Print Styles */
@media print {
    .navbar,
    .btn,
    footer,
    .sample-btn,
    .accordion-button {
        display: none !important;
    }
    
    .card {
        border: 1px solid #000 !important;
        box-shadow: none !important;
    }
    
    .bg-dark,
    .bg-card {
        background: white !important;
        color: black !important;
    }
    
    .text-light,
    .text-primary,
    .text-muted {
        color: black !important;
    }
}

/* High Contrast Mode */
@media (prefers-contrast: high) {
    :root {
        --primary: #4285f4;
        --bg-primary: #000;
        --bg-card: #111;
        --text-primary: #fff;
        --border-secondary: #666;
    }
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    html {
        scroll-behavior: auto;
    }
}

/* Dark Mode (if user has system preference) */
@media (prefers-color-scheme: dark) {
    /* Variables are already optimized for dark mode */
}

/* Custom scrollbar for webkit browsers */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--border-secondary);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* Selection styles */
::selection {
    background-color: rgba(37, 99, 235, 0.3);
    color: var(--text-primary);
}

::-moz-selection {
    background-color: rgba(37, 99, 235, 0.3);
    color: var(--text-primary);
}

/* Focus indicators for keyboard navigation */
.focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

/* Ensure proper contrast for all interactive elements */
a {
    color: var(--primary);
    transition: var(--transition);
}

a:hover {
    color: var(--primary-hover);
}

/* Loading skeleton for better UX */
.skeleton {
    background: linear-gradient(90deg, var(--bg-secondary) 25%, var(--bg-card) 50%, var(--bg-secondary) 75%);
    background-size: 200% 100%;
    animation: loading 1.5s infinite;
    border-radius: var(--border-radius);
    height: 20px;
}

@keyframes loading {
    0% {
        background-position: 200% 0;
    }
    100% {
        background-position: -200% 0;
    }
}

/* Error page styles */
.error-page {
    min-height: 50vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
}

/* Sticky footer helper */
.main-wrapper {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

main {
    flex-grow: 1;
}

/* Performance optimizations */
img {
    max-width: 100%;
    height: auto;
}

/* Ensure proper spacing */
section {
    position: relative;
}

/* Custom utilities */
.text-gradient {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Touch feedback classes */
.touch-active {
    transform: scale(0.98) !important;
    opacity: 0.9 !important;
    transition: all 0.1s ease !important;
}

/* Mobile device specific styles */
.mobile-device .navbar {
    transition: transform 0.3s ease;
}

.mobile-device .keyboard-navigation .btn:focus,
.mobile-device .keyboard-navigation .form-control:focus,
.mobile-device .keyboard-navigation .form-select:focus {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

/* Collapsible content */
.collapsible-content .expanded {
    max-height: none !important;
}