/* ============================================
   KPI Settore Idrotermosanitario (ITS)
   Tema blu/teal (business/analytics)
   ============================================ */

:root {
    --color-bg: #0c1222;
    --color-bg-card: #141c2e;
    --color-surface: #1e2a42;
    
    --color-primary: #0ea5e9;
    --color-primary-dim: #0284c7;
    --color-accent: #06b6d4;
    
    --color-text: #e8f0fc;
    --color-text-muted: #94a8c4;
    --color-text-dim: #64789a;
    
    --color-border: #2d3d5c;
    --color-border-focus: #0ea5e9;
    
    --color-positive: #22c55e;
    --color-negative: #ef4444;
    
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    
    --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.3);
    
    --font-sans: 'Outfit', -apple-system, sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
    
    --transition: 0.2s ease;
}

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

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

body {
    font-family: var(--font-sans);
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
}

body::before {
    content: '';
    position: fixed;
    inset: 0;
    background:
        radial-gradient(ellipse 80% 50% at 50% -20%, rgba(14, 165, 233, 0.1), transparent),
        radial-gradient(ellipse 60% 40% at 100% 100%, rgba(6, 182, 212, 0.06), transparent);
    pointer-events: none;
    z-index: 0;
}

.app-container {
    position: relative;
    z-index: 1;
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem 1.5rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.header {
    margin-bottom: 2rem;
    text-align: center;
}

.back-link {
    display: inline-block;
    font-size: 0.9rem;
    color: var(--color-primary);
    text-decoration: none;
    margin-bottom: 1rem;
    transition: opacity var(--transition);
}

.back-link:hover {
    opacity: 0.8;
}

.header-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo-icon {
    width: 36px;
    height: 36px;
    color: var(--color-primary);
}

.logo h1 {
    font-size: 1.5rem;
    font-weight: 600;
    letter-spacing: -0.02em;
}

.subtitle {
    font-size: 0.9rem;
    color: var(--color-text-muted);
}

.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.intro-card,
.kpi-section,
.calc-card,
.info-card {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 1.5rem 1.75rem;
    box-shadow: var(--shadow-md);
}

.intro-card p {
    margin: 0 0 0.75rem 0;
    font-size: 0.95rem;
    color: var(--color-text-muted);
}

.intro-card p:last-of-type {
    margin-bottom: 0;
}

.intro-card .source {
    font-size: 0.85rem;
    color: var(--color-text-dim);
    margin-top: 1rem;
}

.intro-card a {
    color: var(--color-primary);
    text-decoration: none;
}

.intro-card a:hover {
    text-decoration: underline;
}

.kpi-section h2 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.kpi-num {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 1.75rem;
    height: 1.75rem;
    background: rgba(14, 165, 233, 0.25);
    color: var(--color-primary);
    border-radius: 6px;
    font-size: 0.9rem;
    font-weight: 700;
}

.kpi-subtitle {
    font-size: 0.85rem;
    color: var(--color-text-dim);
    margin-bottom: 1.25rem;
}

.kpi-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 1rem;
}

.kpi-card {
    padding: 1rem 1.25rem;
    background: rgba(0, 0, 0, 0.2);
    border-radius: var(--radius-md);
    border-left: 4px solid var(--color-primary);
}

.kpi-card h3 {
    font-size: 0.95rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--color-primary);
}

.kpi-card p {
    font-size: 0.875rem;
    color: var(--color-text-muted);
    margin: 0;
    line-height: 1.5;
}

.calc-mini {
    margin-top: 0.75rem;
    padding-top: 0.75rem;
    border-top: 1px solid var(--color-border);
}

.calc-mini label {
    font-size: 0.75rem;
    color: var(--color-text-dim);
}

.calc-mini code {
    display: block;
    margin-top: 0.25rem;
    font-family: var(--font-mono);
    font-size: 0.7rem;
    color: var(--color-accent);
}

.calc-card h2 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 1.25rem;
}

.calc-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 1.25rem;
}

.calc-block {
    padding: 1rem;
    background: rgba(0, 0, 0, 0.2);
    border-radius: var(--radius-md);
}

.calc-block h3 {
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--color-text-muted);
}

.form-row {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-row input {
    font-family: var(--font-sans);
    font-size: 0.9rem;
    padding: 0.6rem 0.8rem;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    color: var(--color-text);
}

.form-row input::placeholder {
    color: var(--color-text-dim);
}

.form-row input:focus {
    outline: none;
    border-color: var(--color-border-focus);
    box-shadow: 0 0 0 2px rgba(14, 165, 233, 0.2);
}

.calc-result {
    margin-top: 0.75rem;
    font-family: var(--font-mono);
    font-size: 1rem;
    font-weight: 600;
    color: var(--color-primary);
}

.calc-result.positive {
    color: var(--color-positive);
}

.calc-result.negative {
    color: var(--color-negative);
}

.info-card h3 {
    font-size: 0.95rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
}

.info-card p {
    margin: 0;
    font-size: 0.9rem;
    color: var(--color-text-muted);
}

.footer {
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--color-border);
    text-align: center;
    font-size: 0.8rem;
    color: var(--color-text-dim);
}

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

.footer a:hover {
    text-decoration: underline;
}

@media (max-width: 640px) {
    .app-container {
        padding: 1.5rem 1rem;
    }
    .kpi-grid,
    .calc-grid {
        grid-template-columns: 1fr;
    }
}

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