/* ====================================
   STAYFITWITHAI - Mobile-First CSS Framework
   Version: 2.0
   Mobile-First Approach with Modern Design
   ==================================== */

/* ====================================
   1. CSS Variables & Reset
   ==================================== */
:root {
    /* Colors */
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary: #06b6d4;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --dark: #1f2937;
    --gray: #6b7280;
    --light: #f9fafb;
    --white: #ffffff;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #06b6d4 0%, #3b82f6 100%);
    --gradient-success: linear-gradient(135deg, #10b981 0%, #059669 100%);
    
    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-size-base: 16px;
    --line-height-base: 1.6;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    
    /* Breakpoints */
    --mobile: 375px;
    --tablet: 768px;
    --desktop: 1024px;
    --wide: 1280px;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;
    
    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    --radius-full: 9999px;
}

/* Reset & Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: var(--font-size-base);
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-primary);
    line-height: var(--line-height-base);
    color: var(--dark);
    background-color: var(--white);
    overflow-x: hidden;
}

/* ====================================
   2. Mobile-First Navigation
   ==================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--white);
    box-shadow: var(--shadow-md);
    z-index: 1000;
    transition: transform var(--transition-base);
}

.nav-container {
    max-width: var(--wide);
    margin: 0 auto;
    padding: var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-brand {
    display: flex;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    text-decoration: none;
    color: var(--primary);
    font-size: 1.25rem;
    font-weight: 700;
}

.logo i {
    font-size: 1.5rem;
}

/* Hamburger Menu Button - Mobile First */
.nav-toggle {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 40px;
    height: 40px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: var(--spacing-sm);
    position: relative;
    z-index: 1001;
}

.hamburger {
    width: 24px;
    height: 2px;
    background: var(--dark);
    margin: 3px 0;
    transition: var(--transition-fast);
    transform-origin: center;
}

/* Hamburger Animation */
.nav-toggle.active .hamburger:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
}

.nav-toggle.active .hamburger:nth-child(2) {
    opacity: 0;
}

.nav-toggle.active .hamburger:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
}

/* Mobile Menu - Default State */
.nav-menu {
    position: fixed;
    top: 60px;
    left: -100%;
    width: 80%;
    max-width: 320px;
    height: calc(100vh - 60px);
    background: var(--white);
    box-shadow: var(--shadow-xl);
    transition: left var(--transition-base);
    overflow-y: auto;
    z-index: 999;
}

.nav-menu.active {
    left: 0;
}

/* Mobile Menu Overlay */
.mobile-menu-overlay {
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition-base);
    z-index: 998;
}

.mobile-menu-overlay.active {
    opacity: 1;
    visibility: visible;
}

/* Navigation Links - Mobile */
.nav-links {
    padding: var(--spacing-lg);
}

.nav-item {
    margin-bottom: var(--spacing-md);
}

.nav-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md);
    color: var(--dark);
    text-decoration: none;
    border-radius: var(--radius-md);
    transition: var(--transition-fast);
}

.nav-link:hover {
    background: var(--light);
    color: var(--primary);
}

.nav-link i {
    width: 20px;
    text-align: center;
}

/* Dropdown Menu - Mobile */
.dropdown-menu {
    display: none;
    padding-left: var(--spacing-xl);
    margin-top: var(--spacing-sm);
}

.dropdown.active .dropdown-menu {
    display: block;
}

.dropdown-toggle i:last-child {
    margin-left: auto;
    transition: transform var(--transition-fast);
}

.dropdown.active .dropdown-toggle i:last-child {
    transform: rotate(180deg);
}

.dropdown-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    color: var(--gray);
    text-decoration: none;
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
}

.dropdown-item:hover {
    background: var(--light);
    color: var(--primary);
}

/* CTA Button in Mobile Menu */
.nav-cta {
    padding: var(--spacing-lg);
    border-top: 1px solid var(--light);
}

/* ====================================
   3. Buttons & Forms
   ==================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: 1rem;
    font-weight: 500;
    text-decoration: none;
    border: 2px solid transparent;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition-fast);
    white-space: nowrap;
}

.btn-primary {
    background: var(--gradient-primary);
    color: var(--white);
    border: none;
}

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

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

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

.btn-lg {
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: 1.125rem;
}

.btn-card {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--light);
    color: var(--dark);
}

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

/* Forms */
.form-control {
    width: 100%;
    padding: var(--spacing-md);
    font-size: 1rem;
    border: 2px solid var(--light);
    border-radius: var(--radius-md);
    transition: var(--transition-fast);
}

.form-control:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

/* ====================================
   4. Hero Section - Mobile First
   ==================================== */
.hero {
    padding: calc(60px + var(--spacing-2xl)) var(--spacing-md) var(--spacing-2xl);
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
}

.container {
    width: 100%;
    max-width: var(--wide);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.hero-content {
    text-align: center;
}

.hero-title {
    font-size: 2rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: var(--spacing-lg);
    color: var(--dark);
}

.gradient-text {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.125rem;
    color: var(--gray);
    margin-bottom: var(--spacing-xl);
}

.hero-buttons {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-2xl);
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
    margin-top: var(--spacing-2xl);
}

.stat {
    text-align: center;
}

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

.stat-label {
    font-size: 0.875rem;
    color: var(--gray);
}

.hero-image {
    display: none;
}

/* ====================================
   5. Calculator Cards - Mobile First
   ==================================== */
.calculators {
    padding: var(--spacing-3xl) 0;
    background: var(--light);
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
}

.section-title {
    font-size: 1.875rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
}

.section-subtitle {
    font-size: 1.125rem;
    color: var(--gray);
}

.calculator-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

.calculator-card {
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
    transition: var(--transition-base);
    position: relative;
}

.calculator-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.calculator-card.featured {
    border: 2px solid var(--primary);
}

.featured-badge {
    position: absolute;
    top: -10px;
    right: 20px;
    background: var(--gradient-primary);
    color: var(--white);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 600;
}

.card-icon {
    width: 60px;
    height: 60px;
    background: var(--gradient-primary);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-lg);
}

.card-icon i {
    font-size: 1.5rem;
    color: var(--white);
}

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.card-description {
    color: var(--gray);
    margin-bottom: var(--spacing-lg);
}

.card-stats {
    display: flex;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.stat-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.875rem;
    color: var(--gray);
}

/* ====================================
   6. Email Capture Section
   ==================================== */
.email-capture {
    padding: var(--spacing-3xl) 0;
    background: var(--gradient-primary);
}

.capture-card {
    background: var(--white);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl) var(--spacing-xl);
    box-shadow: var(--shadow-xl);
}

.capture-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
}

.capture-subtitle {
    color: var(--gray);
    margin-bottom: var(--spacing-xl);
}

.capture-form .form-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.form-note {
    font-size: 0.875rem;
    color: var(--gray);
    margin-top: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.form-note a {
    color: var(--primary);
    text-decoration: none;
}

.capture-benefits {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-md);
    margin-top: var(--spacing-xl);
}

.benefit {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--success);
}

/* ====================================
   7. Footer - Mobile First
   ==================================== */
.footer {
    background: var(--dark);
    color: var(--white);
    padding: var(--spacing-2xl) 0 var(--spacing-xl);
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-2xl);
    margin-bottom: var(--spacing-2xl);
}

.footer-logo {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--white);
    text-decoration: none;
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
}

.footer-description {
    color: var(--gray);
    margin-bottom: var(--spacing-lg);
}

.social-links {
    display: flex;
    gap: var(--spacing-md);
}

.social-links a {
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--white);
    text-decoration: none;
    transition: var(--transition-fast);
}

.social-links a:hover {
    background: var(--primary);
}

.footer-links {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
}

.footer-column h4 {
    margin-bottom: var(--spacing-md);
    font-size: 1rem;
}

.footer-column ul {
    list-style: none;
}

.footer-column li {
    margin-bottom: var(--spacing-sm);
}

.footer-column a {
    color: var(--gray);
    text-decoration: none;
    transition: var(--transition-fast);
}

.footer-column a:hover {
    color: var(--white);
}

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-xl);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-bottom p {
    font-size: 0.875rem;
    color: var(--gray);
}

.affiliate-disclosure {
    margin-top: var(--spacing-sm);
    font-size: 0.75rem;
}

/* ====================================
   8. Tablet Styles (768px+)
   ==================================== */
@media (min-width: 768px) {
    /* Navigation - Tablet */
    .nav-toggle {
        display: none;
    }
    
    .nav-menu {
        position: static;
        width: auto;
        height: auto;
        background: transparent;
        box-shadow: none;
        display: flex;
        align-items: center;
        justify-content: space-between;
        flex: 1;
        margin-left: var(--spacing-2xl);
    }
    
    .nav-links {
        display: flex;
        align-items: center;
        gap: var(--spacing-lg);
        padding: 0;
    }
    
    .nav-item {
        margin: 0;
        position: relative;
    }
    
    .dropdown-menu {
        position: absolute;
        top: 100%;
        left: 0;
        min-width: 250px;
        background: var(--white);
        box-shadow: var(--shadow-xl);
        border-radius: var(--radius-md);
        padding: var(--spacing-md);
        opacity: 0;
        visibility: hidden;
        transform: translateY(-10px);
        transition: var(--transition-fast);
    }
    
    .dropdown:hover .dropdown-menu {
        display: block;
        opacity: 1;
        visibility: visible;
        transform: translateY(0);
    }
    
    .nav-cta {
        padding: 0;
        border: none;
    }
    
    /* Hero - Tablet */
    .hero-content {
        max-width: 600px;
        margin: 0 auto;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-buttons {
        flex-direction: row;
        justify-content: center;
    }
    
    /* Calculator Grid - Tablet */
    .calculator-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    /* Email Capture - Tablet */
    .capture-form .form-group {
        flex-direction: row;
    }
    
    .capture-form .form-control {
        flex: 1;
    }
    
    .capture-benefits {
        grid-template-columns: repeat(2, 1fr);
    }
    
    /* Footer - Tablet */
    .footer-links {
        grid-template-columns: repeat(3, 1fr);
    }
}

/* ====================================
   9. Desktop Styles (1024px+)
   ==================================== */
@media (min-width: 1024px) {
    /* Hero - Desktop */
    .hero {
        min-height: 80vh;
    }
    
    .hero .container {
        display: grid;
        grid-template-columns: 1fr 1fr;
        gap: var(--spacing-3xl);
        align-items: center;
    }
    
    .hero-content {
        text-align: left;
        max-width: none;
    }
    
    .hero-title {
        font-size: 3rem;
    }
    
    .hero-buttons {
        justify-content: flex-start;
    }
    
    .hero-image {
        display: block;
    }
    
    .hero-image img {
        width: 100%;
        height: auto;
    }
    
    /* Calculator Grid - Desktop */
    .calculator-grid {
        grid-template-columns: repeat(3, 1fr);
    }
    
    /* Email Capture - Desktop */
    .capture-card {
        display: grid;
        grid-template-columns: 1.5fr 1fr;
        gap: var(--spacing-3xl);
        align-items: center;
    }
    
    /* Footer - Desktop */
    .footer-content {
        grid-template-columns: 1fr 2fr;
        gap: var(--spacing-3xl);
    }
}

/* ====================================
   10. Wide Desktop (1280px+)
   ==================================== */
@media (min-width: 1280px) {
    .container {
        padding: 0 var(--spacing-xl);
    }
    
    .hero-title {
        font-size: 3.5rem;
    }
    
    .calculator-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

/* ====================================
   11. Utilities
   ==================================== */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mt-4 { margin-top: var(--spacing-xl); }

.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }
.mb-4 { margin-bottom: var(--spacing-xl); }

.hidden { display: none !important; }
.visible { display: block !important; }

/* Loading States */
.loading {
    opacity: 0.6;
    pointer-events: none;
}

.spinner {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 2px solid var(--light);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Accessibility */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}