/* Import Inter font from Google Fonts */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

/* CSS Variables for color scheme */
:root {
    --color-background: #f5f5f5;
    --color-card: #ffffff;
    --color-primary: #3b82f6;
    --color-primary-hover: #2563eb;
    --color-success: #10b981;
    --color-neutral: #6b7280;
    --color-text-primary: #1f2937;
    --color-text-secondary: #6b7280;
    --color-border: #e5e7eb;
    --spacing-unit: 8px;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--color-background);
    color: var(--color-text-primary);
    line-height: 1.6;
    padding: calc(var(--spacing-unit) * 4);
}

/* Container */
.container {
    max-width: 800px;
    margin: 0 auto;
}

/* Header */
header {
    text-align: center;
    margin-bottom: calc(var(--spacing-unit) * 6);
}

header h1 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--color-text-primary);
}

/* Input Section - Two-column grid */
.input-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: calc(var(--spacing-unit) * 3);
    margin-bottom: calc(var(--spacing-unit) * 4);
}

/* Input Cards */
.input-card {
    background-color: var(--color-card);
    border-radius: calc(var(--spacing-unit) * 1.5);
    padding: calc(var(--spacing-unit) * 3);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.input-card h2 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: calc(var(--spacing-unit) * 3);
    color: var(--color-text-primary);
}

.input-group {
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.input-group:last-child {
    margin-bottom: 0;
}

.input-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    margin-bottom: calc(var(--spacing-unit) * 1);
}

.input-group input {
    width: 100%;
    padding: calc(var(--spacing-unit) * 1.5);
    font-family: 'Inter', sans-serif;
    font-size: 1rem;
    border: 1px solid var(--color-border);
    border-radius: calc(var(--spacing-unit) * 1);
    transition: border-color 0.2s;
}

.input-group input:focus {
    outline: none;
    border-color: var(--color-primary);
}

.input-group input.input-error {
    border-color: #ef4444;
}

/* Error message styling */
.error-message {
    margin-top: calc(var(--spacing-unit) * 2);
    padding: calc(var(--spacing-unit) * 1.5);
    background-color: #fee2e2;
    color: #991b1b;
    border-radius: calc(var(--spacing-unit) * 1);
    font-size: 0.875rem;
    font-weight: 500;
}

/* Calculate Button - Prominent primary action */
.calculate-button {
    width: 100%;
    padding: calc(var(--spacing-unit) * 2);
    font-family: 'Inter', sans-serif;
    font-size: 1rem;
    font-weight: 600;
    color: white;
    background-color: var(--color-primary);
    border: none;
    border-radius: calc(var(--spacing-unit) * 1);
    cursor: pointer;
    transition: background-color 0.2s;
    margin-bottom: calc(var(--spacing-unit) * 4);
}

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

.calculate-button:active {
    transform: translateY(1px);
}

/* Results Section */
.results-section {
    background-color: var(--color-card);
    border-radius: calc(var(--spacing-unit) * 1.5);
    padding: calc(var(--spacing-unit) * 3);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.results-section.hidden {
    display: none;
}

.results-content {
    display: flex;
    flex-direction: column;
    gap: calc(var(--spacing-unit) * 2);
}

.result-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: calc(var(--spacing-unit) * 1.5);
    border-bottom: 1px solid var(--color-border);
}

.result-item:last-of-type {
    border-bottom: none;
}

.result-label {
    font-weight: 500;
    color: var(--color-text-secondary);
}

.result-value {
    font-weight: 600;
    font-size: 1.125rem;
    color: var(--color-text-primary);
}

/* Verdict Badge */
.verdict-badge {
    margin-top: calc(var(--spacing-unit) * 2);
    padding: calc(var(--spacing-unit) * 2);
    text-align: center;
    font-weight: 600;
    font-size: 1.125rem;
    border-radius: calc(var(--spacing-unit) * 1);
}

.verdict-badge.significant {
    background-color: var(--color-success);
    color: white;
}

.verdict-badge.not-significant {
    background-color: var(--color-neutral);
    color: white;
}

/* Screen reader only content */
.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;
}

/* Focus styles for keyboard navigation */
input:focus,
button:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Responsive Design - Stack cards on mobile */
@media (max-width: 640px) {
    body {
        padding: calc(var(--spacing-unit) * 2);
    }

    header h1 {
        font-size: 1.5rem;
    }

    .input-section {
        grid-template-columns: 1fr;
        gap: calc(var(--spacing-unit) * 2);
    }
}