/* ========================
   CSS Variables
   ======================== */
:root {
    --primary-color: #4caf50;
    --primary-dark: #45a049;
    --primary-light: #81c784;

    --severe-thinness-color: #0d47a1;
    --moderate-thinness-color: #1565c0;
    --mild-thinness-color: #1976d2;
    --underweight-color: #2196f3;
    --normal-color: #4caf50;
    --overweight-color: #ff9800;
    --obese-color: #f44336;
    --obese-class-i-color: #e53935;
    --obese-class-ii-color: #c62828;
    --obese-class-iii-color: #b71c1c;
    --youth-color: #9c27b0;

    --text-primary: #2c3e50;
    --text-secondary: #5a6c7d;
    --text-light: #95a5a6;

    --bg-primary: #f9f9f9;
    --bg-white: #ffffff;
    --bg-light: #f5f7fa;
    --bg-gray: #e8ecf1;

    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.12);
    --shadow-hover: 0 6px 16px rgba(76, 175, 80, 0.15);

    --border-radius: 16px;
    --border-radius-sm: 10px;
    --border-radius-xs: 6px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);

    --container-width: 1200px;
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 32px;
    --spacing-xl: 48px;
    --spacing-2xl: 64px;

    --focus-ring: 0 0 0 3px rgba(76, 175, 80, 0.5);
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family:
        "Inter",
        -apple-system,
        BlinkMacSystemFont,
        "Segoe UI",
        Roboto,
        Oxygen,
        Ubuntu,
        Cantarell,
        "Helvetica Neue",
        sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ========================
   Typography
   ======================== */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-weight: 600;
    line-height: 1.3;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

h1 {
    font-size: 2.25rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

h2 {
    font-size: 1.875rem;
    letter-spacing: -0.01em;
}

h3 {
    font-size: 1.5rem;
}

h4 {
    font-size: 1.25rem;
}

p {
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: var(--transition);
}

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

/* Accessibility: Focus Indicators */
a:focus,
button:focus,
input:focus,
select:focus,
textarea:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

a:focus-visible,
button:focus-visible,
input:focus-visible {
    outline: 3px solid var(--primary-color);
    outline-offset: 2px;
    box-shadow: var(--focus-ring);
}

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

/* Skip to Main Content Link */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--primary-color);
    color: white;
    padding: 8px 16px;
    text-decoration: none;
    z-index: 1000;
    border-radius: 0 0 4px 0;
}

.skip-link:focus {
    top: 0;
}

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

.main {
    flex: 1;
    padding: var(--spacing-xl) 0;
}

/* ========================
   Header & Navigation
   ======================== */
.header {
    background-color: var(--bg-white);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) 0;
    min-height: 64px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 600;
    font-size: 1.25rem;
    transition: var(--transition);
}

.logo img {
    border-radius: var(--border-radius-sm);
    transition: var(--transition);
}

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

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

.nav-links {
    display: flex;
    list-style: none;
    gap: var(--spacing-sm);
    align-items: center;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--border-radius-xs);
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--primary-color);
    background-color: var(--bg-light);
    transform: translateY(-1px);
}

.nav-links a.active {
    font-weight: 600;
}

/* Hamburger Menu Button */
.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    z-index: 101;
    transition: var(--transition);
}

.hamburger span {
    display: block;
    width: 25px;
    height: 3px;
    background-color: var(--text-primary);
    border-radius: 3px;
    transition: var(--transition);
}

.hamburger:hover span {
    background-color: var(--primary-color);
}

.hamburger.active span:nth-child(1) {
    transform: rotate(45deg) translate(8px, 8px);
}

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

.hamburger.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -7px);
}

/* ========================
   Hero Section
   ======================== */
.hero {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
    padding: var(--spacing-xl) 0 var(--spacing-lg);
}

.hero h1 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
    animation: fadeInUp 0.6s ease-out;
}

.subtitle {
    font-size: 1.15rem;
    color: var(--text-secondary);
    margin: 0;
    font-weight: 400;
    animation: fadeInUp 0.6s ease-out 0.1s backwards;
}

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

/* ========================
   Calculator Section
   ======================== */
.calculator-section {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-2xl);
}

.calculator-card {
    background: var(--bg-white);
    border-radius: var(--border-radius);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-lg);
    max-width: 600px;
    margin: 0 auto;
    width: 100%;
    transition: var(--transition);
    animation: fadeInUp 0.6s ease-out 0.2s backwards;
}

.calculator-card:hover {
    box-shadow: var(--shadow-hover);
}

/* ========================
   Unit Toggle
   ======================== */
.unit-toggle {
    display: flex;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-lg);
    background: var(--bg-light);
    padding: 6px;
    border-radius: var(--border-radius-sm);
}

.unit-btn {
    flex: 1;
    padding: 12px 24px;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    border-radius: var(--border-radius-xs);
    transition: var(--transition);
    font-family: inherit;
}

.unit-btn:hover {
    color: var(--text-primary);
    background-color: rgba(76, 175, 80, 0.08);
}

.unit-btn:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

.unit-btn.active {
    background: var(--bg-white);
    color: var(--primary-color);
    box-shadow: var(--shadow-sm);
    font-weight: 600;
}

/* ========================
   Form Styles
   ======================== */
.bmi-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

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

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

@media (max-width: 600px) {
    .personal-inputs {
        grid-template-columns: 1fr;
    }
}

.input-field {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    position: relative;
}

.input-field label {
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.9rem;
    letter-spacing: 0.01em;
}

.input-field input,
.input-field select {
    padding: 14px 16px;
    border: 2px solid var(--bg-gray);
    border-radius: var(--border-radius-sm);
    font-size: 1rem;
    font-family: inherit;
    transition: var(--transition);
    background: var(--bg-white);
    color: var(--text-primary);
    outline: none;
}

.input-field select {
    cursor: pointer;
    appearance: none;
    -webkit-appearance: none;
    -moz-appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%235a6c7d' d='M6 9L1 4h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 16px center;
    padding-right: 48px;
}

.input-field input:hover,
.input-field select:hover {
    border-color: #d0d7de;
}

.input-field input:focus,
.input-field select:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(76, 175, 80, 0.1);
    outline: none;
}

.input-field input:focus-visible,
.input-field select:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

.input-field input::placeholder {
    color: var(--text-light);
}

/* Improve input accessibility */
.input-field input:invalid:not(:placeholder-shown) {
    border-color: var(--obese-color);
}

.input-field input:valid:not(:placeholder-shown) {
    border-color: var(--normal-color);
}

/* Imperial Height Inputs */
.input-field-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.input-field-group > label {
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.9rem;
}

.height-imperial {
    display: flex;
    gap: var(--spacing-sm);
}

.height-imperial .input-field {
    flex: 1;
    position: relative;
}

.input-suffix {
    position: absolute;
    right: 16px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-light);
    font-weight: 500;
    pointer-events: none;
    font-size: 0.9rem;
}

.height-imperial .input-field input {
    padding-right: 42px;
}

/* ========================
   Buttons
   ======================== */
.btn-calculate {
    padding: 16px 32px;
    background: linear-gradient(135deg, var(--primary-color) 0%, #45a049 100%);
    color: white;
    border: none;
    border-radius: var(--border-radius-sm);
    font-size: 1.05rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    font-family: inherit;
    box-shadow: var(--shadow-md);
    letter-spacing: 0.01em;
}

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

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

.btn-calculate:focus-visible {
    outline: 3px solid var(--primary-dark);
    outline-offset: 2px;
}

.btn-reset {
    padding: 12px 24px;
    background: var(--bg-light);
    color: var(--text-primary);
    border: 2px solid var(--bg-gray);
    border-radius: var(--border-radius-sm);
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    font-family: inherit;
}

.btn-reset:hover {
    background: var(--bg-gray);
    border-color: #cbd5e0;
    transform: translateY(-1px);
}

.btn-reset:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* ========================
   Results Section
   ======================== */
.results {
    animation: fadeIn 0.5s ease-in-out;
}

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

.result-header {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.result-header h2 {
    color: var(--text-primary);
    margin: 0;
    font-size: 1.5rem;
}

.bmi-value {
    text-align: center;
    margin: var(--spacing-xl) 0;
}

.bmi-value span {
    font-size: 4.5rem;
    font-weight: 800;
    color: var(--primary-color);
    line-height: 1;
    letter-spacing: -0.02em;
    display: inline-block;
    animation: scaleIn 0.5s ease-out;
}

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.5);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

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

.bmi-category span {
    display: inline-block;
    padding: 10px 28px;
    border-radius: 50px;
    font-size: 1.15rem;
    font-weight: 600;
    color: white;
    background: var(--normal-color);
    box-shadow: var(--shadow-md);
    animation: slideIn 0.5s ease-out 0.2s backwards;
}

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

/* Category Colors */
.bmi-category.severe-thinness span {
    background: linear-gradient(
        135deg,
        var(--severe-thinness-color) 0%,
        #0a3d91 100%
    );
}

.bmi-category.moderate-thinness span {
    background: linear-gradient(
        135deg,
        var(--moderate-thinness-color) 0%,
        #0d47a1 100%
    );
}

.bmi-category.mild-thinness span {
    background: linear-gradient(
        135deg,
        var(--mild-thinness-color) 0%,
        #1565c0 100%
    );
}

.bmi-category.underweight span {
    background: linear-gradient(
        135deg,
        var(--underweight-color) 0%,
        #1976d2 100%
    );
}

.bmi-category.normal span {
    background: linear-gradient(135deg, var(--normal-color) 0%, #45a049 100%);
}

.bmi-category.overweight span {
    background: linear-gradient(
        135deg,
        var(--overweight-color) 0%,
        #f57c00 100%
    );
}

.bmi-category.obese span {
    background: linear-gradient(135deg, var(--obese-color) 0%, #d32f2f 100%);
}

.bmi-category.obese-class-i span {
    background: linear-gradient(
        135deg,
        var(--obese-class-i-color) 0%,
        #d32f2f 100%
    );
}

.bmi-category.obese-class-ii span {
    background: linear-gradient(
        135deg,
        var(--obese-class-ii-color) 0%,
        #b71c1c 100%
    );
}

.bmi-category.obese-class-iii span {
    background: linear-gradient(
        135deg,
        var(--obese-class-iii-color) 0%,
        #a11818 100%
    );
}

.bmi-category.youth span {
    background: linear-gradient(135deg, var(--youth-color) 0%, #7b1fa2 100%);
}

/* ========================
   BMI Gauge
   ======================== */
.bmi-gauge {
    margin: var(--spacing-xl) 0;
    position: relative;
}

.gauge-bar {
    display: flex;
    height: 48px;
    border-radius: 24px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.gauge-segment {
    flex: 1;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.gauge-segment::after {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(
        180deg,
        rgba(255, 255, 255, 0.2) 0%,
        transparent 100%
    );
}

.gauge-segment.underweight {
    background: var(--underweight-color);
}

.gauge-segment.normal {
    background: var(--normal-color);
}

.gauge-segment.overweight {
    background: var(--overweight-color);
}

.gauge-segment.obese {
    background: var(--obese-color);
}

.gauge-pointer {
    position: absolute;
    top: -10px;
    width: 0;
    height: 0;
    border-left: 12px solid transparent;
    border-right: 12px solid transparent;
    border-top: 18px solid var(--text-primary);
    transform: translateX(-12px);
    transition: left 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.2));
}

.gauge-labels {
    display: flex;
    justify-content: space-between;
    margin-top: var(--spacing-md);
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.gauge-labels span {
    flex: 1;
    text-align: center;
}

/* ========================
   BMI Description
   ======================== */
.bmi-description {
    background: var(--bg-light);
    padding: var(--spacing-md);
    border-radius: var(--border-radius-sm);
    margin-bottom: var(--spacing-md);
    border-left: 4px solid var(--primary-color);
}

.bmi-description p {
    color: var(--text-secondary);
    margin: 0 0 var(--spacing-sm) 0;
    line-height: 1.7;
    font-size: 0.95rem;
    white-space: pre-line;
}

.bmi-description p:last-child {
    margin-bottom: 0;
}

/* ========================
   Info Section
   ======================== */
.info-section {
    background: var(--bg-white);
    border-radius: var(--border-radius);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
    max-width: 800px;
    margin: 0 auto;
    animation: fadeInUp 0.6s ease-out 0.3s backwards;
}

.info-section h2 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

.info-section p {
    color: var(--text-secondary);
    line-height: 1.7;
}

.bmi-ranges {
    margin: var(--spacing-lg) 0;
}

.bmi-ranges h3 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

.category-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.category-list li {
    padding: var(--spacing-md);
    background: var(--bg-light);
    border-radius: var(--border-radius-sm);
    color: var(--text-secondary);
    border-left: 4px solid var(--primary-color);
    transition: var(--transition);
}

.category-list li:hover {
    background: rgba(76, 175, 80, 0.05);
    transform: translateX(4px);
}

.category-list li:nth-child(1) {
    border-left-color: var(--underweight-color);
}

.category-list li:nth-child(2) {
    border-left-color: var(--normal-color);
}

.category-list li:nth-child(3) {
    border-left-color: var(--overweight-color);
}

.category-list li:nth-child(4) {
    border-left-color: var(--obese-color);
}

.category-list strong {
    color: var(--text-primary);
}

.disclaimer {
    margin-top: var(--spacing-lg);
    padding: var(--spacing-md);
    background: #fff3cd;
    border-left: 4px solid #ffc107;
    border-radius: var(--border-radius-sm);
}

.disclaimer h4 {
    color: #856404;
    margin-bottom: var(--spacing-sm);
}

.disclaimer p {
    color: #856404;
    margin: 0;
    font-size: 0.9rem;
    line-height: 1.6;
}

/* ========================
   Footer
   ======================== */
.footer {
    background: #f5f5f5;
    margin-top: auto;
    padding: var(--spacing-lg) 0;
    border-top: 1px solid #e0e0e0;
    text-align: center;
}

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

.footer-links {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
    font-size: 0.875rem;
}

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

.footer-links span {
    color: var(--text-light);
    font-size: 0.875rem;
}

.footer-contact {
    margin: var(--spacing-xs) 0;
    font-size: 0.875rem;
}

.footer-contact a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
}

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

.footer-copyright {
    color: var(--text-light);
    font-size: 0.8125rem;
    margin: var(--spacing-xs) 0 0;
}

/* Responsive footer */
@media (max-width: 768px) {
    .footer-links {
        font-size: 0.8125rem;
        gap: var(--spacing-xs);
    }

    .footer-contact {
        font-size: 0.8125rem;
    }

    .footer-copyright {
        font-size: 0.75rem;
    }
}

/* ========================
   Legal Pages
   ======================== */
.legal-page {
    background: var(--bg-white);
    border-radius: var(--border-radius);
    padding: var(--spacing-2xl);
    box-shadow: var(--shadow-md);
    max-width: 900px;
    margin: 0 auto;
}

.legal-page h1 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
    font-size: 2.5rem;
}

.last-updated {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-md);
    border-bottom: 2px solid var(--bg-gray);
}

.legal-section {
    margin-bottom: var(--spacing-xl);
}

.legal-section h2 {
    color: var(--text-primary);
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    font-size: 1.75rem;
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--bg-gray);
}

.legal-section:first-of-type h2 {
    margin-top: 0;
    border-top: none;
    padding-top: 0;
}

.legal-section h3 {
    color: var(--text-primary);
    margin-top: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
    font-size: 1.35rem;
}

.legal-section h4 {
    color: var(--text-primary);
    margin-top: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
    font-size: 1.1rem;
}

.legal-section p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: var(--spacing-md);
}

.legal-section ul,
.legal-section ol {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: var(--spacing-md);
    padding-left: var(--spacing-lg);
}

.legal-section li {
    margin-bottom: var(--spacing-xs);
}

.legal-section a {
    color: var(--primary-color);
    text-decoration: underline;
    transition: var(--transition);
}

.legal-section a:hover {
    color: var(--primary-dark);
}

.legal-section strong {
    color: var(--text-primary);
    font-weight: 600;
}

.contact-list {
    list-style: none;
    padding-left: 0;
}

.contact-list li {
    padding: var(--spacing-xs) 0;
}

.disclaimer-highlight {
    background: #fff3cd;
    border-left: 4px solid #ffc107;
    padding: var(--spacing-md);
    border-radius: var(--border-radius-sm);
    color: #856404;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
}

/* ========================
   Responsive Design
   ======================== */

/* Tablets and below (<768px) */
@media (max-width: 768px) {
    :root {
        --spacing-lg: 24px;
        --spacing-xl: 32px;
        --spacing-2xl: 48px;
    }

    h1 {
        font-size: 1.875rem;
    }

    h2 {
        font-size: 1.625rem;
    }

    h3 {
        font-size: 1.35rem;
    }

    .subtitle {
        font-size: 1.05rem;
    }

    .hero {
        padding: var(--spacing-lg) 0 var(--spacing-md);
        margin-bottom: var(--spacing-xl);
    }

    .calculator-card {
        padding: var(--spacing-lg);
    }

    .bmi-value span {
        font-size: 3.5rem;
    }

    .bmi-category span {
        font-size: 1.05rem;
        padding: 8px 24px;
    }

    .gauge-bar {
        height: 40px;
    }

    .footer-content {
        gap: var(--spacing-lg);
    }

    .legal-page {
        padding: var(--spacing-xl);
    }

    .legal-page h1 {
        font-size: 2rem;
    }
}

/* Mobile (<480px) */
@media (max-width: 480px) {
    :root {
        --spacing-md: 16px;
        --spacing-lg: 20px;
        --spacing-xl: 28px;
        --spacing-2xl: 40px;
    }

    html {
        font-size: 15px;
    }

    h1 {
        font-size: 1.75rem;
    }

    h2 {
        font-size: 1.5rem;
    }

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

    .logo span {
        font-size: 1.1rem;
    }

    .logo img {
        width: 32px;
        height: 32px;
    }

    /* Mobile Navigation */
    .hamburger {
        display: flex;
    }

    .nav-links {
        position: fixed;
        top: 64px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 64px);
        background-color: var(--bg-white);
        flex-direction: column;
        gap: 0;
        padding: var(--spacing-md);
        box-shadow: var(--shadow-lg);
        transition: left 0.3s ease-in-out;
        overflow-y: auto;
    }

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

    .nav-links li {
        width: 100%;
        border-bottom: 1px solid var(--bg-gray);
    }

    .nav-links li:last-child {
        border-bottom: none;
    }

    .nav-links a {
        display: block;
        width: 100%;
        padding: var(--spacing-md);
        font-size: 1rem;
        border-radius: 0;
    }

    .nav-links a:hover,
    .nav-links a.active {
        background-color: var(--bg-light);
        transform: none;
    }

    .hero {
        padding: var(--spacing-md) 0;
        margin-bottom: var(--spacing-lg);
    }

    .calculator-card {
        padding: var(--spacing-md);
        border-radius: var(--border-radius-sm);
    }

    .unit-toggle {
        gap: 4px;
        padding: 4px;
    }

    .unit-btn {
        padding: 10px 16px;
        font-size: 0.9rem;
    }

    .input-group {
        gap: var(--spacing-sm);
    }

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

    .bmi-category span {
        font-size: 1rem;
        padding: 8px 20px;
    }

    .gauge-bar {
        height: 36px;
    }

    .gauge-pointer {
        border-left-width: 10px;
        border-right-width: 10px;
        border-top-width: 14px;
        transform: translateX(-10px);
    }

    .gauge-labels {
        font-size: 0.75rem;
    }

    .btn-calculate {
        padding: 14px 24px;
        font-size: 1rem;
    }

    .info-section {
        padding: var(--spacing-md);
    }

    .footer-content {
        flex-direction: column;
        gap: var(--spacing-md);
    }

    .footer-section {
        min-width: 100%;
    }

    .legal-page {
        padding: var(--spacing-md);
    }

    .legal-page h1 {
        font-size: 1.75rem;
    }
}

/* Extra Small Mobile (<360px) */
@media (max-width: 360px) {
    .height-imperial {
        flex-direction: column;
    }

    .bmi-value span {
        font-size: 2.5rem;
    }

    .calculator-card {
        padding: var(--spacing-sm);
    }
}

/* Desktop Large (>1024px) */
@media (min-width: 1024px) {
    .hero {
        padding: var(--spacing-2xl) 0 var(--spacing-xl);
    }

    .calculator-card {
        padding: var(--spacing-2xl);
    }

    .info-section {
        padding: var(--spacing-2xl);
    }

    .legal-page {
        padding: var(--spacing-2xl) 3rem;
    }

    .footer-content {
        gap: var(--spacing-2xl);
    }
}

/* High Contrast Mode Support */
@media (prefers-contrast: high) {
    :root {
        --text-primary: #000000;
        --text-secondary: #1a1a1a;
        --bg-gray: #cccccc;
    }

    .btn-calculate,
    .unit-btn.active {
        border: 2px solid currentColor;
    }
}

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

/* Print Styles */
@media print {
    .header,
    .footer,
    .btn-calculate,
    .btn-reset,
    .unit-toggle {
        display: none;
    }

    .calculator-card,
    .legal-page {
        box-shadow: none;
        border: 1px solid var(--bg-gray);
        padding: 1rem;
    }

    body {
        background: white;
    }
}