/**
 * Kids BMI Calculator App Styles
 *
 * A production-ready BMI-for-age percentile calculator with accessible, responsive design
 * Based on adult BMI calculator styles with additions for age/sex inputs and percentile chart
 */

/* ========================================
   App Container
   ======================================== */

.app-container {
    width: 100%;
    max-width: 700px;
    margin: 0 auto;
}

/* ========================================
   Kids BMI Calculator Container
   ======================================== */

.kids-bmi-calculator {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    padding: var(--space-6);
}

/* ========================================
   Unit Toggle
   ======================================== */

.bmi-unit-toggle {
    display: flex;
    gap: var(--space-2);
    margin-bottom: var(--space-6);
    background: var(--color-bg-alt);
    padding: var(--space-1);
    border-radius: var(--radius-md);
}

.bmi-unit-btn {
    flex: 1;
    padding: var(--space-2) var(--space-4);
    background: transparent;
    border: none;
    border-radius: var(--radius-sm);
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-text-muted);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.bmi-unit-btn:hover {
    color: var(--color-text);
}

.bmi-unit-btn.active {
    background: var(--color-primary);
    color: white;
    box-shadow: var(--shadow-sm);
}

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

/* ========================================
   Demographics Section (Age & Sex)
   ======================================== */

.bmi-demographics {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-4);
    margin-bottom: var(--space-4);
    padding-bottom: var(--space-4);
    border-bottom: 1px solid var(--color-border);
}

.age-field label,
.sex-field label {
    display: block;
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-text);
    margin-bottom: var(--space-2);
}

/* Age inputs */
.age-inputs {
    display: flex;
    gap: var(--space-2);
}

.age-input-group {
    flex: 1;
}

.age-input-group select {
    width: 100%;
    padding: var(--space-3);
    font-size: var(--font-size-base);
    color: var(--color-text);
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.age-input-group select:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-alpha);
}

/* Sex selection */
.sex-options {
    display: flex;
    gap: var(--space-3);
}

.sex-option {
    flex: 1;
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-3);
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.sex-option:hover {
    border-color: var(--color-primary);
}

.sex-option input[type="radio"] {
    width: 18px;
    height: 18px;
    accent-color: var(--color-primary);
}

.sex-option input[type="radio"]:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

.sex-option input[type="radio"]:checked + .sex-label {
    color: var(--color-primary);
    font-weight: 600;
}

.sex-label {
    font-size: var(--font-size-sm);
    color: var(--color-text);
}

/* ========================================
   Form Fields
   ======================================== */

.bmi-form {
    display: flex;
    flex-direction: column;
    gap: var(--space-4);
}

.bmi-input-group {
    display: none;
    grid-template-columns: 1fr;
    gap: var(--space-4);
}

.bmi-input-group.active {
    display: grid;
}

.bmi-field {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.bmi-field label {
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-text);
}

.bmi-field input[type="number"] {
    width: 100%;
    padding: var(--space-3);
    font-size: var(--font-size-base);
    color: var(--color-text);
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.bmi-field input[type="number"]:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-alpha);
}

.bmi-field input[type="number"].error {
    border-color: var(--color-danger);
}

.bmi-field input[type="number"].error:focus {
    box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.1);
}

.field-error {
    font-size: var(--font-size-xs);
    color: var(--color-danger);
    min-height: 1em;
}

.has-error input,
.has-error select {
    border-color: var(--color-danger);
}

/* Imperial height fields (feet and inches) */
.bmi-field-group {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.bmi-field-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-3);
}

.bmi-field-row .bmi-field {
    position: relative;
}

.field-unit {
    position: absolute;
    right: var(--space-3);
    top: 50%;
    transform: translateY(-50%);
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
    pointer-events: none;
}

.bmi-field-row .bmi-field input[type="number"] {
    padding-right: var(--space-8);
}

/* ========================================
   Submit Button
   ======================================== */

.bmi-btn {
    padding: var(--space-3) var(--space-6);
    font-size: var(--font-size-base);
    font-weight: 600;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.bmi-btn-primary {
    background: var(--color-primary);
    color: white;
    box-shadow: var(--shadow-md);
}

.bmi-btn-primary:hover {
    background: var(--color-primary-dark);
    box-shadow: var(--shadow-lg);
    transform: translateY(-1px);
}

.bmi-btn-primary:active {
    transform: translateY(0);
    box-shadow: var(--shadow-sm);
}

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

/* ========================================
   Result Section
   ======================================== */

.bmi-result {
    margin-top: var(--space-6);
    padding-top: var(--space-6);
    border-top: 1px solid var(--color-border);
    text-align: center;
}

.bmi-result[hidden] {
    display: none;
}

.bmi-result-title {
    font-size: var(--font-size-lg);
    margin-bottom: var(--space-4);
    color: var(--color-text-muted);
}

.bmi-score {
    font-size: 4rem;
    font-weight: 700;
    line-height: 1;
    margin-bottom: var(--space-2);
    color: var(--color-primary);
}

/* Percentile Display */
.percentile-display {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    margin-bottom: var(--space-4);
    font-size: var(--font-size-lg);
}

.percentile-label {
    color: var(--color-text-muted);
}

.percentile-value {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--color-primary);
}

/* Category Badge */
.bmi-category {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--space-6);
    padding: var(--space-2) var(--space-4);
    border-radius: var(--radius-md);
    display: inline-block;
}

.bmi-category.underweight {
    background: rgba(59, 130, 246, 0.1);
    color: #3b82f6;
}

.bmi-category.healthy {
    background: rgba(34, 197, 94, 0.1);
    color: #22c55e;
}

.bmi-category.overweight {
    background: rgba(245, 158, 11, 0.1);
    color: #f59e0b;
}

.bmi-category.obesity {
    background: rgba(239, 68, 68, 0.1);
    color: #ef4444;
}

.bmi-category.severe-obesity {
    background: rgba(127, 29, 29, 0.1);
    color: #7f1d1d;
}

/* ========================================
   Percentile Chart
   ======================================== */

.percentile-chart {
    margin: var(--space-6) 0;
    position: relative;
}

.percentile-chart-bar {
    display: grid;
    grid-template-columns: 5fr 80fr 10fr 5fr;
    border-radius: var(--radius-md);
    overflow: hidden;
    margin-bottom: var(--space-2);
}

.percentile-range {
    padding: var(--space-3);
    text-align: center;
    display: flex;
    flex-direction: column;
    gap: var(--space-1);
    transition: transform var(--transition-fast);
}

.percentile-range.active {
    transform: scale(1.05);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    z-index: 1;
}

.percentile-range.underweight {
    background: rgba(59, 130, 246, 0.15);
    color: #1d4ed8; /* Darkened from #2563eb for 4.5:1 contrast */
}

.percentile-range.healthy {
    background: rgba(34, 197, 94, 0.15);
    color: #166534; /* Darkened from #15803d for 4.5:1 contrast on #def6e7 */
}

.percentile-range.overweight {
    background: rgba(245, 158, 11, 0.15);
    color: #92400e; /* Darkened from #d97706 for 4.5:1 contrast */
}

.percentile-range.obesity {
    background: rgba(239, 68, 68, 0.15);
    color: #b91c1c; /* Darkened from #dc2626 for 4.5:1 contrast */
}

.range-label {
    font-size: var(--font-size-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.range-value {
    font-size: var(--font-size-xs);
    /* Removed opacity: 0.8 to maintain color contrast ratio */
}

.percentile-indicator {
    position: absolute;
    bottom: -8px;
    width: 0;
    height: 0;
    border-left: 8px solid transparent;
    border-right: 8px solid transparent;
    border-bottom: 12px solid var(--color-primary);
    transform: translateX(-50%);
    transition: left var(--transition-fast);
    display: none;
}

/* ========================================
   BMI Info
   ======================================== */

.bmi-info {
    margin-top: var(--space-4);
    padding: var(--space-4);
    background: var(--color-bg-alt);
    border-radius: var(--radius-md);
    border-left: 4px solid var(--color-primary);
}

.bmi-info-text {
    font-size: var(--font-size-sm);
    line-height: 1.6;
    color: var(--color-text);
    margin: 0;
}

/* Related Calculator Link */
.related-calculator {
    margin-top: var(--space-6);
    padding: var(--space-4);
    background: var(--color-bg-alt);
    border-radius: var(--radius-md);
    text-align: center;
}

.related-calculator p {
    margin: 0;
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
}

.related-calculator a {
    color: var(--color-primary);
    font-weight: 500;
    text-decoration: none;
}

.related-calculator a:hover {
    text-decoration: underline;
}

/* ========================================
   Use Cases Section
   ======================================== */

.use-cases {
    margin-top: var(--space-8);
    padding: var(--space-6);
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
}

.use-cases h2 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--space-3);
}

.use-cases-intro {
    color: var(--color-text-muted);
    margin-bottom: var(--space-4);
}

.use-cases-list {
    list-style: none;
    padding: 0;
    margin: 0;
    display: grid;
    gap: var(--space-4);
}

.use-cases-list li {
    padding: var(--space-4);
    background: var(--color-bg-alt);
    border-radius: var(--radius-md);
    border-left: 3px solid var(--color-primary);
}

.use-cases-list strong {
    display: block;
    margin-bottom: var(--space-2);
    color: var(--color-text);
    font-weight: 600;
}

.use-cases-list p {
    margin: 0;
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
    line-height: 1.6;
}

/* ========================================
   FAQ Section
   ======================================== */

.faq-section {
    margin-top: var(--space-8);
    padding: var(--space-6);
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
}

.faq-section h2 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--space-4);
}

.faq-list {
    margin: 0;
}

.faq-item {
    padding: var(--space-4);
    border-bottom: 1px solid var(--color-border);
}

.faq-item:last-child {
    border-bottom: none;
}

.faq-item dt {
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: var(--space-2);
}

.faq-item dd {
    margin: 0;
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
    line-height: 1.6;
}

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

@media (max-width: 640px) {
    .kids-bmi-calculator {
        padding: var(--space-4);
    }

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

    .age-inputs {
        flex-direction: row;
    }

    .sex-options {
        flex-direction: row;
    }

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

    .percentile-chart-bar {
        grid-template-columns: 1fr 1fr;
        gap: var(--space-1);
    }

    .percentile-range {
        padding: var(--space-2);
    }

    .range-label {
        font-size: var(--font-size-2xs);
    }

    .range-value {
        font-size: var(--font-size-2xs);
    }

    .percentile-indicator {
        display: none;
    }
}

@media (min-width: 641px) {
    .bmi-input-group.metric-inputs,
    .bmi-input-group.imperial-inputs {
        grid-template-columns: 1fr 1fr;
    }
}

/* ========================================
   Help Panel
   ======================================== */

.help-panel {
    position: fixed;
    inset: 0;
    z-index: 200;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-4);
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
}

.help-panel[hidden] {
    display: none;
}

.help-content {
    background: var(--color-bg-card);
    border-radius: var(--radius-lg);
    max-width: 500px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-xl);
}

.help-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-4) var(--space-6);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    background: var(--color-bg-card);
}

.help-header h2 {
    font-size: var(--font-size-lg);
    margin: 0;
}

.help-close {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-xl);
    border-radius: var(--radius-md);
    color: var(--color-text-muted);
}

.help-close:hover {
    background: var(--color-bg-alt);
    color: var(--color-text);
}

.help-close:focus-visible {
    outline: none;
    box-shadow: var(--focus-ring);
}

.help-body {
    padding: var(--space-6);
}

.help-section {
    margin-bottom: var(--space-6);
}

.help-section:last-child {
    margin-bottom: 0;
}

.help-section h3 {
    font-size: var(--font-size-base);
    margin-bottom: var(--space-4);
    color: var(--color-text);
}

.help-steps {
    margin: 0;
    padding-left: var(--space-5);
}

.help-steps li {
    margin-bottom: var(--space-2);
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
}

.help-features {
    margin: 0;
    padding-left: var(--space-5);
}

.help-features li {
    margin-bottom: var(--space-2);
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
}

/* ========================================
   Header Actions
   ======================================== */

.nav-actions {
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.btn-icon {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-full);
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-text-muted);
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    cursor: pointer;
}

.btn-icon:hover {
    background: var(--color-border);
    color: var(--color-text);
}

.btn-icon:focus-visible {
    outline: none;
    box-shadow: var(--focus-ring);
}

/* ========================================
   Share Button
   ======================================== */

.bmi-share-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    margin-top: var(--space-4);
    padding: var(--space-2) var(--space-4);
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-text);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.bmi-share-btn:hover {
    background: var(--color-primary);
    border-color: var(--color-primary);
    color: white;
}

.bmi-share-btn:focus-visible {
    outline: none;
    box-shadow: var(--focus-ring);
}

.bmi-share-btn[hidden] {
    display: none;
}

.bmi-share-btn svg {
    flex-shrink: 0;
}

/* ========================================
   Toast Notification
   ======================================== */

.bmi-toast {
    position: fixed;
    bottom: var(--space-6);
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--color-text);
    color: var(--color-bg);
    padding: var(--space-3) var(--space-5);
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: 500;
    box-shadow: var(--shadow-lg);
    z-index: 1000;
    opacity: 0;
    transition: transform 0.3s ease, opacity 0.3s ease;
}

.bmi-toast.visible {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
}

.bmi-toast.success {
    background: #22c55e;
    color: white;
}

/* ========================================
   Print Styles
   ======================================== */

@media print {
    .help-panel,
    .nav-actions,
    .bmi-share-btn {
        display: none;
    }

    .kids-bmi-calculator {
        box-shadow: none;
        border: 1px solid #ccc;
    }
}