/* ===================================
   DESIGN SYSTEM & CSS VARIABLES
   =================================== */

:root {
    /* Color Palette */
    --primary-50: #f0f4ff;
    --primary-100: #e0e7ff;
    --primary-200: #c7d2fe;
    --primary-300: #a5b4fc;
    --primary-400: #818cf8;
    --primary-500: #667eea;
    --primary-600: #5568d3;
    --primary-700: #4c51bf;
    --primary-800: #434190;
    --primary-900: #3c366b;

    --secondary-500: #764ba2;
    --secondary-600: #6b3fa0;

    --success-400: #34d399;
    --success-500: #10b981;

    --warning-400: #fbbf24;
    --warning-500: #f59e0b;

    --error-400: #f87171;
    --error-500: #ef4444;

    --info-400: #60a5fa;
    --info-500: #3b82f6;

    /* Neutral Colors */
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;

    /* Background Colors */
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-success: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --gradient-warm: linear-gradient(135deg, #fa709a 0%, #fee140 100%);
    --gradient-cool: linear-gradient(135deg, #30cfd0 0%, #330867 100%);

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    --spacing-3xl: 6rem;

    /* Border Radius */
    --radius-sm: 0.5rem;
    --radius-md: 1rem;
    --radius-lg: 1.5rem;
    --radius-xl: 2rem;
    --radius-full: 9999px;

    /* 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);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    --shadow-glow: 0 0 30px rgba(102, 126, 234, 0.3);

    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-display: 'Outfit', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ===================================
   RESET & BASE STYLES
   =================================== */

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

body {
    font-family: var(--font-primary);
    background: var(--bg-primary);
    color: var(--gray-100);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ===================================
   UTILITY CLASSES
   =================================== */

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

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

.glass-card {
    background: rgba(30, 41, 59, 0.7);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    transition: all var(--transition-base);
}

.glass-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-2xl), var(--shadow-glow);
    border-color: rgba(102, 126, 234, 0.3);
}

/* ===================================
   HEADER
   =================================== */

.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    padding: var(--spacing-md) 0;
    animation: slideDown 0.5s ease-out;
}

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

    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    cursor: pointer;
    transition: transform var(--transition-base);
}

.logo:hover {
    transform: scale(1.05);
}

.logo svg {
    filter: drop-shadow(0 0 10px rgba(102, 126, 234, 0.5));
}

.logo-text {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
}

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

.nav {
    display: flex;
    gap: var(--spacing-lg);
}

.nav-link {
    color: var(--gray-300);
    text-decoration: none;
    font-weight: 500;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    transition: all var(--transition-base);
    position: relative;
}

.nav-link::before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%) scaleX(0);
    width: 80%;
    height: 2px;
    background: var(--gradient-primary);
    transition: transform var(--transition-base);
}

.nav-link:hover,
.nav-link.active {
    color: white;
}

.nav-link:hover::before,
.nav-link.active::before {
    transform: translateX(-50%) scaleX(1);
}

/* ===================================
   HERO SECTION
   =================================== */

.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: var(--spacing-3xl) 0;
    overflow: hidden;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 0;
    overflow: hidden;
}

.gradient-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.3;
    animation: float 20s ease-in-out infinite;
}

.orb-1 {
    width: 500px;
    height: 500px;
    background: var(--gradient-primary);
    top: -250px;
    left: -250px;
    animation-delay: 0s;
}

.orb-2 {
    width: 400px;
    height: 400px;
    background: var(--gradient-secondary);
    bottom: -200px;
    right: -200px;
    animation-delay: 5s;
}

.orb-3 {
    width: 300px;
    height: 300px;
    background: var(--gradient-success);
    top: 50%;
    right: 10%;
    animation-delay: 10s;
}

@keyframes float {

    0%,
    100% {
        transform: translate(0, 0) scale(1);
    }

    33% {
        transform: translate(30px, -30px) scale(1.1);
    }

    66% {
        transform: translate(-20px, 20px) scale(0.9);
    }
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
    text-align: center;
    margin: 0 auto;
    animation: fadeInUp 1s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    background: rgba(102, 126, 234, 0.1);
    border: 1px solid rgba(102, 126, 234, 0.3);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: var(--spacing-lg);
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {

    0%,
    100% {
        box-shadow: 0 0 0 0 rgba(102, 126, 234, 0.4);
    }

    50% {
        box-shadow: 0 0 0 10px rgba(102, 126, 234, 0);
    }
}

.badge-icon {
    font-size: 1.2rem;
    animation: rotate 3s linear infinite;
}

@keyframes rotate {
    from {
        transform: rotate(0deg);
    }

    to {
        transform: rotate(360deg);
    }
}

.hero-title {
    font-family: var(--font-display);
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
    color: white;
}

.hero-description {
    font-size: 1.25rem;
    color: var(--gray-300);
    margin-bottom: var(--spacing-xl);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-cta {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: var(--spacing-2xl);
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 1rem 2rem;
    border-radius: var(--radius-full);
    font-weight: 600;
    font-size: 1rem;
    text-decoration: none;
    border: none;
    cursor: pointer;
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.btn:hover::before {
    width: 300px;
    height: 300px;
}

.btn span,
.btn svg {
    position: relative;
    z-index: 1;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 15px 40px rgba(102, 126, 234, 0.4);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.1);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.15);
    border-color: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
}

.btn-full {
    width: 100%;
    justify-content: center;
}

.hero-stats {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--spacing-xl);
    flex-wrap: wrap;
}

.stat-item {
    text-align: center;
}

.stat-number {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--gray-400);
    margin-top: var(--spacing-xs);
}

.stat-divider {
    width: 1px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
}

/* ===================================
   BMI CALCULATOR SECTION
   =================================== */

.bmi-section {
    padding: var(--spacing-3xl) 0;
    position: relative;
}

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

.section-title {
    font-family: var(--font-display);
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 700;
    color: white;
    margin-bottom: var(--spacing-md);
}

.section-description {
    font-size: 1.125rem;
    color: var(--gray-400);
    max-width: 600px;
    margin: 0 auto;
}

.bmi-calculator-wrapper {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: var(--spacing-xl);
    align-items: start;
}

.calculator-card,
.results-card {
    padding: var(--spacing-xl);
}

.card-header {
    margin-bottom: var(--spacing-xl);
}

.card-header h3 {
    font-family: var(--font-display);
    font-size: 1.75rem;
    font-weight: 700;
    color: white;
    margin-bottom: var(--spacing-xs);
}

.card-header p {
    color: var(--gray-400);
}

/* Form Styles */

.bmi-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

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

.form-label {
    font-weight: 600;
    color: var(--gray-200);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.optional {
    font-weight: 400;
    color: var(--gray-500);
    text-transform: none;
    font-size: 0.75rem;
}

/* Gender Selector */

.gender-selector {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
}

.gender-selector input[type="radio"] {
    display: none;
}

.gender-option {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-lg);
    background: rgba(255, 255, 255, 0.05);
    border: 2px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-base);
}

.gender-option:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: rgba(102, 126, 234, 0.3);
}

.gender-selector input[type="radio"]:checked+.gender-option {
    background: rgba(102, 126, 234, 0.2);
    border-color: var(--primary-500);
    box-shadow: 0 0 20px rgba(102, 126, 234, 0.3);
}

.gender-option svg {
    width: 32px;
    height: 32px;
    color: var(--gray-400);
    transition: color var(--transition-base);
}

.gender-selector input[type="radio"]:checked+.gender-option svg {
    color: var(--primary-400);
}

.gender-option span {
    font-weight: 600;
    color: var(--gray-300);
}

.gender-selector input[type="radio"]:checked+.gender-option span {
    color: white;
}

/* Input Wrapper */

.input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

.form-input {
    width: 100%;
    padding: 1rem 3.5rem 1rem 1rem;
    background: rgba(255, 255, 255, 0.05);
    border: 2px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-md);
    color: white;
    font-size: 1rem;
    font-family: var(--font-primary);
    transition: all var(--transition-base);
}

.form-input:focus {
    outline: none;
    background: rgba(255, 255, 255, 0.08);
    border-color: var(--primary-500);
    box-shadow: 0 0 0 4px rgba(102, 126, 234, 0.1);
}

.form-input::placeholder {
    color: var(--gray-500);
}

.input-unit {
    position: absolute;
    right: 1rem;
    color: var(--gray-400);
    font-weight: 600;
    pointer-events: none;
}

/* Input Slider */

.input-slider {
    margin-top: var(--spacing-sm);
}

.input-slider input[type="range"] {
    width: 100%;
    height: 6px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-full);
    outline: none;
    -webkit-appearance: none;
}

.input-slider input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    background: var(--gradient-primary);
    border-radius: 50%;
    cursor: pointer;
    box-shadow: 0 2px 10px rgba(102, 126, 234, 0.5);
    transition: all var(--transition-base);
}

.input-slider input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.7);
}

.input-slider input[type="range"]::-moz-range-thumb {
    width: 20px;
    height: 20px;
    background: var(--gradient-primary);
    border-radius: 50%;
    cursor: pointer;
    border: none;
    box-shadow: 0 2px 10px rgba(102, 126, 234, 0.5);
    transition: all var(--transition-base);
}

.input-slider input[type="range"]::-moz-range-thumb:hover {
    transform: scale(1.2);
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.7);
}

.slider-labels {
    display: flex;
    justify-content: space-between;
    margin-top: var(--spacing-xs);
    font-size: 0.75rem;
    color: var(--gray-500);
}

/* Results Card */

.results-placeholder {
    text-align: center;
    padding: var(--spacing-2xl) 0;
}

.placeholder-icon {
    margin-bottom: var(--spacing-lg);
    animation: float 3s ease-in-out infinite;
}

.results-placeholder h3 {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
    margin-bottom: var(--spacing-sm);
}

.results-placeholder p {
    color: var(--gray-400);
    max-width: 300px;
    margin: 0 auto;
}

.results-content {
    animation: fadeInUp 0.5s ease-out;
}

.result-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-xl);
}

.result-header h3 {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
}

.btn-reset {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-md);
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-full);
    color: var(--gray-300);
    font-size: 0.875rem;
    cursor: pointer;
    transition: all var(--transition-base);
}

.btn-reset:hover {
    background: rgba(255, 255, 255, 0.1);
    color: white;
}

/* BMI Display */

.bmi-display {
    background: rgba(102, 126, 234, 0.05);
    border: 1px solid rgba(102, 126, 234, 0.2);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.bmi-value-wrapper {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.bmi-label {
    font-size: 0.875rem;
    color: var(--gray-400);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: var(--spacing-xs);
}

.bmi-value {
    font-family: var(--font-display);
    font-size: 4rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1;
    margin-bottom: var(--spacing-sm);
}

.bmi-category {
    font-size: 1.25rem;
    font-weight: 600;
    color: white;
    padding: var(--spacing-xs) var(--spacing-md);
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-full);
    display: inline-block;
}

/* BMI Gauge */

.bmi-gauge {
    position: relative;
    padding: var(--spacing-md) 0;
}

.gauge-svg {
    width: 100%;
    height: auto;
    max-width: 450px;
    margin: 0 auto;
    display: block;
}

.gauge-segment {
    opacity: 0.5;
    transition: all var(--transition-slow);
    filter: brightness(0.7);
}

.gauge-segment.active {
    opacity: 1;
    filter: brightness(1.3) drop-shadow(0 0 12px currentColor);
    animation: gaugePulse 2s ease-in-out infinite;
}

@keyframes gaugePulse {

    0%,
    100% {
        filter: brightness(1.3) drop-shadow(0 0 12px currentColor);
    }

    50% {
        filter: brightness(1.5) drop-shadow(0 0 18px currentColor);
    }
}

#gauge-needle {
    transition: transform 1.8s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.gauge-labels {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: var(--spacing-md);
    padding: 0 var(--spacing-sm);
    position: relative;
}

.gauge-label {
    font-size: 0.75rem;
    color: var(--gray-500);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    transition: all var(--transition-base);
}

.gauge-label-left {
    text-align: left;
    flex: 1;
}

.gauge-label-center-left {
    text-align: center;
    flex: 1;
}

.gauge-label-center-right {
    text-align: center;
    flex: 1;
}

.gauge-label-right {
    text-align: right;
    flex: 1;
}

.gauge-label.active {
    color: white;
    font-size: 0.875rem;
    transform: scale(1.1);
}

/* BMI Info Cards */

.bmi-info {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.info-card {
    display: flex;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.05);
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
}

.info-card:hover {
    background: rgba(255, 255, 255, 0.05);
    border-color: rgba(255, 255, 255, 0.1);
}

.info-icon {
    font-size: 2rem;
    flex-shrink: 0;
}

.info-content h4 {
    font-weight: 600;
    color: white;
    margin-bottom: var(--spacing-xs);
}

.info-content p {
    color: var(--gray-400);
    font-size: 0.875rem;
    line-height: 1.6;
}

/* ===================================
   ABOUT SECTION
   =================================== */

.about-section {
    padding: var(--spacing-3xl) 0;
    background: rgba(30, 41, 59, 0.3);
}

.about-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
}

.about-card {
    padding: var(--spacing-xl);
    text-align: center;
}

.about-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
    display: inline-block;
    animation: bounce 2s ease-in-out infinite;
}

@keyframes bounce {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-10px);
    }
}

.about-card h3 {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
    margin-bottom: var(--spacing-md);
}

.about-card p {
    color: var(--gray-400);
    line-height: 1.8;
}

.about-card strong {
    color: var(--gray-200);
}

.bmi-categories {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    text-align: left;
}

.category-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.category-dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    flex-shrink: 0;
}

/* ===================================
   FOOTER
   =================================== */

.footer {
    background: var(--bg-secondary);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding: var(--spacing-2xl) 0 var(--spacing-lg);
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer-brand {
    max-width: 400px;
}

.footer-description {
    color: var(--gray-400);
    margin-top: var(--spacing-md);
    line-height: 1.6;
    font-size: 0.9375rem;
}

.footer-links {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--spacing-md) var(--spacing-xl);
}

.footer-links a {
    color: var(--gray-400);
    text-decoration: none;
    font-size: 0.9375rem;
    font-weight: 500;
    transition: all var(--transition-base);
    position: relative;
    padding-bottom: 0.25rem;
}

.footer-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: width var(--transition-base);
}

.footer-links a:hover {
    color: var(--primary-400);
}

.footer-links a:hover::after {
    width: 100%;
}

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

.footer-bottom p {
    color: var(--gray-500);
    font-size: 0.875rem;
    margin-bottom: var(--spacing-xs);
}

.disclaimer {
    font-size: 0.75rem;
    color: var(--gray-600);
}

/* ===================================
   RESPONSIVE DESIGN
   =================================== */

@media (max-width: 768px) {
    .nav {
        display: none;
    }

    .hero {
        padding-top: 10rem;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .hero-description {
        font-size: 1rem;
    }

    .hero-cta {
        flex-direction: column;
    }

    .btn {
        width: 100%;
        justify-content: center;
    }

    .bmi-calculator-wrapper {
        grid-template-columns: 1fr;
    }

    .about-grid {
        grid-template-columns: 1fr;
    }

    .stat-divider {
        display: none;
    }
}

@media (max-width: 480px) {
    :root {
        font-size: 14px;
    }

    .container {
        padding: 0 var(--spacing-sm);
    }

    .hero {
        min-height: auto;
        padding: 10rem 0 var(--spacing-2xl) 0;
    }

    .section-title {
        font-size: 2rem;
    }

    .bmi-value {
        font-size: 3rem;
    }

    .gender-selector {
        grid-template-columns: 1fr;
    }
}

/* ===================================
   ANIMATIONS & INTERACTIONS
   =================================== */

@media (prefers-reduced-motion: reduce) {

    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Loading Animation */
@keyframes shimmer {
    0% {
        background-position: -1000px 0;
    }

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

.loading {
    animation: shimmer 2s infinite linear;
    background: linear-gradient(to right,
            rgba(255, 255, 255, 0.05) 0%,
            rgba(255, 255, 255, 0.1) 50%,
            rgba(255, 255, 255, 0.05) 100%);
    background-size: 1000px 100%;
}