/* ============================================
   Calcolatore Coibentazione - Stili
   Design moderno, accessibile, responsive
   ============================================ */

:root {
    /* Palette - Tema tecnico industriale */
    --color-bg: #0f1419;
    --color-bg-elevated: #1a2332;
    --color-bg-card: #1e2a3a;
    --color-surface: #243447;
    
    --color-primary: #00d4aa;
    --color-primary-dim: #00a88a;
    --color-accent: #3b82f6;
    --color-warning: #f59e0b;
    
    --color-text: #e8edf4;
    --color-text-muted: #94a3b8;
    --color-text-dim: #64748b;
    
    --color-border: #334155;
    --color-border-focus: #00d4aa;
    
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.4);
    
    --font-sans: 'Outfit', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', 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;
}

/* Background pattern */
body::before {
    content: '';
    position: fixed;
    inset: 0;
    background: 
        radial-gradient(ellipse 80% 50% at 50% -20%, rgba(0, 212, 170, 0.08), transparent),
        radial-gradient(ellipse 60% 40% at 100% 100%, rgba(59, 130, 246, 0.06), transparent);
    pointer-events: none;
    z-index: 0;
}

.app-container {
    position: relative;
    z-index: 1;
    max-width: 560px;
    margin: 0 auto;
    padding: 2rem 1.5rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ========== Header ========== */
.header {
    margin-bottom: 2.5rem;
    text-align: center;
}

.back-link {
    display: inline-block;
    font-size: 0.9rem;
    color: var(--color-primary);
    text-decoration: none;
    margin-bottom: 1rem;
    transition: opacity 0.2s;
}

.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);
    font-weight: 400;
}

/* ========== Main content ========== */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

/* ========== Cards ========== */
.calculator-card,
.result-card,
.info-card {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 1.75rem;
    box-shadow: var(--shadow-md);
}

.calculator-card .card-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 1.5rem;
}

.result-card .result-header {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.result-header-top {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.card-header h2,
.result-header h2 {
    font-size: 1.1rem;
    font-weight: 600;
}

.result-buttons {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex-shrink: 0;
}

.result-value {
    margin-top: 0.25rem;
}

.btn-print {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.5rem 0.9rem;
    font-family: var(--font-sans);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-primary);
    background: rgba(0, 212, 170, 0.12);
    border: 1px solid rgba(0, 212, 170, 0.3);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: background var(--transition), border-color var(--transition);
}

.btn-print:hover {
    background: rgba(0, 212, 170, 0.2);
    border-color: var(--color-primary);
}

.btn-print svg {
    width: 18px;
    height: 18px;
}

.norm-badge {
    font-size: 0.7rem;
    padding: 0.25rem 0.6rem;
    background: rgba(0, 212, 170, 0.15);
    color: var(--color-primary);
    border-radius: 999px;
    font-weight: 500;
}

/* ========== Form ========== */
.calc-form {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.form-group label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-text-muted);
}

.form-group select {
    font-family: var(--font-sans);
    font-size: 0.95rem;
    padding: 0.75rem 1rem;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text);
    cursor: pointer;
    transition: border-color var(--transition), box-shadow var(--transition);
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%2394a3b8' stroke-width='2'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 1rem center;
    padding-right: 2.5rem;
}

.form-group select:hover {
    border-color: var(--color-text-dim);
}

.form-group select:focus {
    outline: none;
    border-color: var(--color-border-focus);
    box-shadow: 0 0 0 3px rgba(0, 212, 170, 0.2);
}

.input-hint {
    font-size: 0.75rem;
    color: var(--color-text-dim);
}

/* Checkbox */
.checkbox-group {
    flex-direction: row;
    align-items: center;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    cursor: pointer;
    font-weight: 400 !important;
    color: var(--color-text) !important;
}

.checkbox-label input {
    position: absolute;
    opacity: 0;
    width: 0;
    height: 0;
}

.checkmark {
    width: 20px;
    height: 20px;
    background: var(--color-surface);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-sm);
    flex-shrink: 0;
    transition: all var(--transition);
}

.checkbox-label input:checked + .checkmark {
    background: var(--color-primary);
    border-color: var(--color-primary);
}

.checkmark {
    position: relative;
}

.checkbox-label input:checked + .checkmark::after {
    content: '';
    position: absolute;
    left: 6px;
    top: 2px;
    width: 5px;
    height: 10px;
    border: solid var(--color-bg);
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}

/* Button */
.btn-calculate {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 1rem 1.5rem;
    font-family: var(--font-sans);
    font-size: 1rem;
    font-weight: 600;
    color: var(--color-bg);
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dim) 100%);
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: transform var(--transition), box-shadow var(--transition);
    margin-top: 0.5rem;
}

.btn-calculate:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 20px rgba(0, 212, 170, 0.35);
}

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

.btn-icon {
    width: 20px;
    height: 20px;
}

/* ========== Result card ========== */
.result-card {
    border-color: rgba(0, 212, 170, 0.2);
}

.result-value {
    font-family: var(--font-mono);
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--color-primary);
    line-height: 1.5;
}

.result-value.has-value {
    animation: pulse 0.5s ease;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

.result-details {
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--color-border);
    font-size: 0.9rem;
    color: var(--color-text-muted);
    line-height: 1.7;
}

.result-note {
    margin-top: 1rem;
    padding: 0.75rem;
    background: rgba(0, 0, 0, 0.2);
    border-radius: var(--radius-sm);
    font-size: 0.8rem;
    color: var(--color-text-dim);
}

.result-note p {
    margin: 0;
}

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

.info-card ul {
    list-style: none;
    font-size: 0.85rem;
    color: var(--color-text-muted);
}

.info-card li {
    padding: 0.35rem 0;
    padding-left: 1.25rem;
    position: relative;
}

.info-card li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--color-primary);
}

/* ========== Footer ========== */
.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);
}

/* ========== Responsive ========== */
@media (max-width: 480px) {
    .app-container {
        padding: 1.5rem 1rem;
    }
    
    .logo h1 {
        font-size: 1.25rem;
    }
    
    .calculator-card,
    .result-card,
    .info-card {
        padding: 1.25rem;
    }
    
    .result-value {
        font-size: 0.9rem;
    }
}

/* Focus visible per accessibilità */
:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Stampa */
@media print {
    body::before { display: none; }
    .calculator-card, .btn-print, .btn-calculate { display: none !important; }
    .result-card, .info-card { box-shadow: none; border-color: #ccc; }
    body { background: #fff; color: #000; }
    .result-value { color: #0a7; }
}