/* CSS Reset & Variables */
:root {
    --primary-color: #0e6caf;
    --primary-dark: #0b5993;
    --primary-light: #e0f2fe;
    
    --bg-color: #f8fafc;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --text-light: #f8fafc;
    
    --card-bg: rgba(255, 255, 255, 0.8);
    --card-border: rgba(255, 255, 255, 0.4);
    --card-shadow: 0 10px 40px rgba(0, 0, 0, 0.05);
    
    --border-radius: 16px;
    
    --underweight: #3b82f6;
    --normal: #22c55e;
    --overweight: #f59e0b;
    --obese: #ef4444;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', sans-serif;
}

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

.grid-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header & Nav mirroring Wisdom Imbibe */
.site-header {
    background-color: var(--primary-color);
    padding: 15px 0;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    text-align: center;
}

.site-logo {
    display: flex;
    justify-content: center;
}

.site-logo img {
    max-width: 300px; /* appropriately scaled */
    height: auto;
}

.main-navigation {
    background-color: #000000;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.inside-navigation {
    display: flex;
    justify-content: center;
}

.main-nav ul {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    margin: 0;
    padding: 0;
}

.main-nav ul li a {
    display: block;
    padding: 15px 20px;
    color: #fff;
    text-decoration: none;
    font-weight: 500;
    font-size: 15px;
    transition: background-color 0.2s;
}

.main-nav ul li a:hover {
    background-color: rgba(255, 255, 255, 0.15);
}

@media (max-width: 768px) {
    .main-nav ul {
        flex-direction: column;
        display: none; /* In a full app, a menu toggle JS logic handles this */
    }
    .menu-toggle {
        display: block;
        width: 100%;
        background: none;
        border: none;
        color: white;
        padding: 15px;
        font-size: 16px;
        cursor: pointer;
    }
    .inside-navigation {
        flex-direction: column;
    }
    /* Let's show list for simple preview */
    .main-nav ul {
        display: flex;
    }
}
.menu-toggle {
    display: none;
}

/* Main Content & Layout */
.main-content {
    flex: 1;
    display: flex;
    justify-content: center;
    padding: 60px 20px;
    background: linear-gradient(135deg, #f0f9ff 0%, #e0f2fe 100%);
}

.calculator-section {
    max-width: 800px;
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 50px;
}

/* Glassmorphism Card */
.glass-card {
    background: var(--card-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--card-border);
    border-radius: var(--border-radius);
    padding: 40px;
    box-shadow: var(--card-shadow);
    max-width: 500px;
    margin: 0 auto;
    width: 100%;
}

.card-title {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary-dark);
    margin-bottom: 8px;
    text-align: center;
}

.card-subtitle {
    font-size: 15px;
    color: var(--text-muted);
    margin-bottom: 30px;
    text-align: center;
}

/* Tabs */
.tabs {
    display: flex;
    background-color: #f1f5f9;
    border-radius: 8px;
    padding: 4px;
    margin-bottom: 30px;
}

.tab-btn {
    flex: 1;
    padding: 10px;
    border: none;
    background: transparent;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-muted);
    cursor: pointer;
    transition: all 0.3s ease;
}

.tab-btn.active {
    background-color: #fff;
    color: var(--primary-color);
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

/* Inputs */
.input-group {
    display: flex;
    flex-direction: column;
    gap: 20px;
    animation: fadeIn 0.4s ease;
}

.hidden {
    display: none !important;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(5px); }
    to { opacity: 1; transform: translateY(0); }
}

.input-row {
    display: flex;
    gap: 15px;
}

.input-field {
    display: flex;
    flex-direction: column;
    gap: 8px;
    flex: 1;
}

.input-field label {
    font-size: 14px;
    font-weight: 500;
    color: #475569;
}

.input-field input {
    padding: 14px 16px;
    border: 1px solid #cbd5e1;
    border-radius: 8px;
    font-size: 16px;
    transition: all 0.3s;
    background-color: #fff;
}

.input-field input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(14, 108, 175, 0.1);
}

.input-field input.error {
    border-color: var(--obese);
}

/* Button */
.calculate-btn {
    width: 100%;
    margin-top: 30px;
    padding: 16px;
    background-color: var(--primary-color);
    color: #fff;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.1s;
}

.calculate-btn:hover {
    background-color: var(--primary-dark);
}

.calculate-btn:active {
    transform: scale(0.98);
}

/* Result Area */
.result-area {
    margin-top: 35px;
    padding-top: 35px;
    border-top: 1px solid #e2e8f0;
    text-align: center;
}

.bmi-score h2 {
    font-size: 48px;
    font-weight: 700;
    line-height: 1;
    margin-bottom: 5px;
    color: var(--text-main);
    transition: color 0.3s;
}

#bmi-category {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 25px;
}

.underweight-text { color: var(--underweight); }
.normal-text { color: var(--normal); }
.overweight-text { color: var(--overweight); }
.obese-text { color: var(--obese); }

/* Progress Bar */
.progress-bar-container {
    padding: 0 10px;
}

.progress-bar {
    height: 12px;
    background: linear-gradient(to right, var(--underweight) 0%, var(--underweight) 24%, var(--normal) 24.1%, var(--normal) 49%, var(--overweight) 49.1%, var(--overweight) 74%, var(--obese) 74.1%, var(--obese) 100%);
    border-radius: 10px;
    position: relative;
    margin-bottom: 15px;
}

.progress-marker {
    position: absolute;
    top: 50%;
    transform: translate(-50%, -50%);
    width: 20px;
    height: 20px;
    background-color: #fff;
    border: 3px solid var(--text-main);
    border-radius: 50%;
    left: 0%;
    transition: left 0.8s cubic-bezier(0.34, 1.56, 0.64, 1);
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
}

.scale-labels {
    display: flex;
    justify-content: space-between;
    font-size: 12px;
    color: var(--text-muted);
    font-weight: 500;
}

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

/* SEO Content Section */
.seo-content {
    background-color: #fff;
    padding: 40px;
    border-radius: var(--border-radius);
    box-shadow: var(--card-shadow);
}

.seo-content h2 {
    color: var(--primary-dark);
    margin-bottom: 15px;
    font-size: 24px;
}

.seo-content h3 {
    color: var(--primary-color);
    margin-top: 25px;
    margin-bottom: 10px;
    font-size: 20px;
}

.seo-content p {
    margin-bottom: 15px;
    color: #334155;
}

.seo-content ul {
    margin-left: 20px;
    margin-bottom: 15px;
}

.seo-content li {
    margin-bottom: 8px;
    color: #334155;
}

/* Footer */
.site-footer {
    background-color: #f1f5f9;
    color: var(--text-muted);
    text-align: center;
    padding: 25px 0;
    margin-top: auto;
    font-size: 14px;
}

/* Responsive tweaks */
@media (max-width: 500px) {
    .glass-card {
        padding: 30px 20px;
    }
    
    .seo-content {
        padding: 30px 20px;
    }
}