/* Reset and Base Styles */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

/* Skip Link */
.skip-link {
    position: absolute;
    top: -40px; /* Hide off-screen */
    left: 0;
    background: var(--primary-color);
    color: white;
    padding: 8px;
    z-index: 10000; /* Ensure it's on top */
    transition: top 0.3s;
}

.skip-link:focus {
    top: 0; /* Bring into view on focus */
}

/* Theme Variables */
:root {
    /* Light Theme Colors - Purple/Blue/White Palette */
    --primary-color: #6D28D9; /* Purple */
    --secondary-color: #3B82F6; /* Blue */
    --accent-color: #F97316; /* Orange for highlights */
    --text-dark: #1F2937;
    --text-light: #6B7280;
    --background-light: #F3F4F6; /* Slightly off-white */
    --white: #FFFFFF;
    --card-bg: #FFFFFF;
    --border-color: #E5E7EB;
    --shadow-color: rgba(0, 0, 0, 0.08); /* Softer shadow */
    --hover-shadow: rgba(0, 0, 0, 0.12); /* Softer shadow */
    --gradient-start: var(--primary-color);
    --gradient-end: var(--secondary-color);
    
    /* Enhanced Spacing System */
    --space-xxs: 0.25rem;
    --space-xs: 0.5rem;
    --space-sm: 0.75rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-xxl: 3rem;
    
    /* Z-index System */
    --z-negative: -1;
    --z-base: 1;
    --z-header: 100;
    --z-dropdown: 200;
    --z-sticky: 300;
    --z-modal: 400;
    --z-toast: 500;
    
    /* Animation Timing */
    --transition-fast: 150ms;
    --transition-normal: 300ms;
    --transition-slow: 500ms;
    
    /* Focus Ring */
    --focus-ring-color: rgba(59, 130, 246, 0.5);
    --focus-ring-width: 3px;
}

[data-theme="dark"] {
    /* Dark Theme Colors - Purple/Blue Palette */
    --primary-color: #8B5CF6; /* Lighter Purple */
    --secondary-color: #60A5FA; /* Lighter Blue */
    --accent-color: #F97316; /* Orange for highlights */
    --text-dark: #F3F4F6; /* Light Gray */
    --text-light: #9CA3AF; /* Gray */
    --background-light: #1F2937; /* Dark Gray for lighter elements in dark mode */
    --white: #111827; /* Very Dark Gray background */
    --card-bg: #1F2937; /* Dark Gray card */
    --border-color: #374151; /* Darker Gray border */
    --shadow-color: rgba(0, 0, 0, 0.3);
    --hover-shadow: rgba(0, 0, 0, 0.4);
    --gradient-start: var(--primary-color);
    --gradient-end: var(--secondary-color);
}

html {
    font-size: 16px;
    scroll-behavior: smooth; /* Already present, ensure it stays */
}

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    overflow-x: hidden;
    background-color: var(--white);
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
    color: var(--text-dark);
}

h1 {
    font-size: 2.8rem; /* Slightly smaller */
}

h2 {
    font-size: 2.2rem; /* Slightly smaller */
}

h3 {
    font-size: 1.6rem; /* Adjusted for better hierarchy */
}

p {
    margin-bottom: 1rem;
    color: var(--text-light);
}

/* Enhanced Focus Styles */
:focus-visible {
    outline: var(--focus-ring-width) solid var(--focus-ring-color);
    outline-offset: 2px;
    border-radius: 4px;
}

/* Loading States */
/* Progressive Loading Bar */
.loading {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background-color: var(--background-light);
    z-index: var(--z-sticky);
}

/* Loading Skeleton */
.skeleton {
    background: linear-gradient(
        90deg,
        var(--background-light) 25%,
        var(--border-color) 37%,
        var(--background-light) 63%
    );
    background-size: 400% 100%;
    animation: skeleton-loading 1.4s ease infinite;
}

@keyframes skeleton-loading {
    0% {
        background-position: 100% 50%;
    }
    100% {
        background-position: 0 50%;
    }
}

.loading::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 20%;
    height: 100%;
    background-color: var(--primary-color);
    animation: loading 1s ease infinite;
}

@keyframes loading {
    0% {
        left: -20%;
    }
    100% {
        left: 100%;
    }
}

/* Floating Price Calculator Widget */
.floating-calculator-widget {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    background-color: var(--card-bg);
    padding: 1.5rem;
    border-radius: 0.5rem;
    box-shadow: 0 6px 12px var(--shadow-color);
    z-index: 1001; /* Above back-to-top, below header */
    width: 300px;
    transform: translateY(120%); /* Start hidden below */
    transition: transform 0.4s ease-in-out;
    border: 1px solid var(--border-color);
}

.floating-calculator-widget.visible {
    transform: translateY(0);
}

.floating-calculator-widget h4 {
    margin-top: 0;
    margin-bottom: 1rem;
    font-size: 1.1rem;
    color: var(--text-dark);
}

.close-floating-calc {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-light);
    padding: 0.25rem;
    line-height: 1;
}

.close-floating-calc:hover {
    color: var(--text-dark);
}

.price-calculator-floating {
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
}

.price-calculator-floating .form-group {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.5rem;
    margin-bottom: 0; /* Override default form-group margin */
}

.price-calculator-floating label {
    font-size: 0.9em;
    color: var(--text-light);
    flex-shrink: 0;
}

.price-calculator-floating select,
.price-calculator-floating input[type="number"] {
    padding: 0.3rem 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: 0.25rem;
    font-size: 0.9em;
    background-color: var(--white);
    color: var(--text-dark);
    max-width: 100px; /* Limit width */
}

.floating-price-display {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 0.5rem;
    padding-top: 0.5rem;
    border-top: 1px solid var(--border-color);
}

.floating-price-display .price-label {
    font-weight: 500;
    color: var(--text-dark);
}

.floating-price-amount {
    font-weight: 700;
    font-size: 1.1em;
    color: var(--primary-color);
}

.btn-small {
    padding: 0.5rem 1rem;
    font-size: 0.9em;
    margin-top: 0.5rem;
}

/* Visually Hidden Class (if not already present) */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Enhanced Scroll-triggered Animations */
.section {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity var(--transition-normal) ease-out, 
                transform var(--transition-normal) ease-out;
    will-change: opacity, transform;
}

/* Sticky Header */
.header.sticky {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: var(--card-bg);
    box-shadow: 0 2px 8px var(--shadow-color);
    animation: slideDown var(--transition-normal) ease;
    z-index: var(--z-header);
}

@keyframes slideDown {
    from {
        transform: translateY(-100%);
    }
    to {
        transform: translateY(0);
    }
}

/* Toast Notifications */
.toast-container {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
    z-index: var(--z-toast);
}

.toast {
    padding: var(--space-md);
    border-radius: 6px;
    background-color: var(--card-bg);
    box-shadow: 0 4px 12px var(--shadow-color);
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    animation: toastSlideIn var(--transition-normal) ease;
    max-width: 400px;
}

.toast-success {
    border-left: 4px solid #10B981;
}

.toast-error {
    border-left: 4px solid #EF4444;
}

.toast-info {
    border-left: 4px solid var(--secondary-color);
}

@keyframes toastSlideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

.section.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Back to Top Button */
.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem; /* Position near FAB */
    background-color: var(--primary-color);
    color: var(--white);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 8px var(--shadow-color);
    opacity: 0; /* Hidden by default */
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease, transform 0.3s ease;
    z-index: 998; /* Below header but above most content */
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background-color: var(--secondary-color);
    transform: scale(1.1);
}

.back-to-top i.bi {
    font-size: 1.2rem;
}

/* Micro-animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

@keyframes pulse {
    0% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
    100% {
        transform: scale(1);
    }
}

@keyframes shimmer {
    0% {
        background-position: -1000px 0;
    }
    100% {
        background-position: 1000px 0;
    }
}

/* Animation Classes */
.animate-fadeIn {
    animation: fadeIn 0.6s ease forwards;
}

.animate-slideIn {
    animation: slideInRight 0.6s ease forwards;
}

.animate-pulse {
    animation: pulse 2s infinite;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 0.375rem;
    font-weight: 500;
    text-decoration: none;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
    position: relative;
    overflow: hidden;
}

.btn::after {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: -100%;
    background: linear-gradient(to right, rgba(255,255,255,0) 0%, rgba(255,255,255,0.2) 50%, rgba(255,255,255,0) 100%);
    transition: left 0.3s ease;
}

.btn:hover::after {
    left: 100%;
}

.btn-primary {
    background-color: var(--accent-color); /* Use Orange for primary CTAs */
    color: var(--white);
}

.btn-primary:hover {
    background-color: #EA580C; /* Darker Orange */
    transform: translateY(-2px);
    box-shadow: 0 4px 6px var(--shadow-color);
}

.btn-secondary {
    background-color: var(--secondary-color); /* Use Blue for secondary */
    color: var(--white);
}

.btn-secondary:hover {
    background-color: #2563EB; /* Darker Blue */
    transform: translateY(-2px);
    box-shadow: 0 4px 6px var(--shadow-color);
}

/* Enhanced Card Styles */
.card {
    background-color: var(--card-bg);
    border-radius: 0.5rem;
    padding: 2rem;
    box-shadow: 0 4px 6px var(--shadow-color);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(45deg, transparent 0%, rgba(255,255,255,0.1) 50%, transparent 100%);
    transform: translateX(-100%);
    transition: transform 0.6s ease;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 12px var(--hover-shadow);
}

.card:hover::before {
    transform: translateX(100%);
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Section */
.section {
    padding: 5rem 0;
    opacity: 0;
    transform: translateY(20px);
    animation: fadeIn 0.6s ease forwards;
}

/* Grid System */
.grid {
    display: grid;
    gap: 2rem;
}

.grid-2 {
    grid-template-columns: repeat(2, 1fr);
}

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

.grid-4 {
    grid-template-columns: repeat(4, 1fr);
}

/* Utilities */
.text-center {
    text-align: center;
}

.mb-2 {
    margin-bottom: 2rem;
}

.mb-4 {
    margin-bottom: 4rem;
}

.mt-2 {
    margin-top: 2rem;
}

.mt-4 {
    margin-top: 4rem;
}

/* Loading Placeholder */
.loading-placeholder {
    background: linear-gradient(90deg, 
        var(--background-light) 25%, 
        var(--border-color) 50%, 
        var(--background-light) 75%
    );
    background-size: 1000px 100%;
    animation: shimmer 2s infinite;
}

/* Theme Switcher */
.theme-switch {
    position: fixed;
    bottom: 2rem;
    left: 2rem;
    z-index: 1000;
    width: 3rem;
    height: 3rem;
    border-radius: 50%;
    background-color: var(--card-bg);
    box-shadow: 0 2px 4px var(--shadow-color);
    border: none;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-switch:hover {
    transform: scale(1.1);
}

/* Responsive */
@media (max-width: 768px) {
    html {
        font-size: 14px;
    }

    .grid-2, .grid-3, .grid-4 {
        grid-template-columns: 1fr;
    }

    .container {
        padding: 0 1rem;
    }

    .section {
        padding: 3rem 0;
    }
}

@media (min-width: 769px) and (max-width: 1024px) {
    .grid-3, .grid-4 {
        grid-template-columns: repeat(2, 1fr);
    }
}