/* Reset e variabili CSS - Stile Apple Moderno */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Colori principali - Tema scuro Apple */
    --background-dark: #000000;
    --background-card: #1c1c1e;
    --background-button: #2c2c2e;
    --background-button-hover: #3a3a3c;
    --background-operator: #ff9f0a;
    --background-operator-hover: #ffb340;
    --background-equals: #ff9f0a;
    --background-equals-hover: #ffb340;
    --background-function: #a5a5a7;
    --background-function-hover: #b5b5b7;
    
    /* Colori testo */
    --text-primary: #ffffff;
    --text-secondary: #8e8e93;
    --text-dark: #000000;
    
    /* Ombre e bordi */
    --shadow-light: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-medium: 0 4px 16px rgba(0, 0, 0, 0.4);
    --shadow-heavy: 0 8px 32px rgba(0, 0, 0, 0.5);
    --border-radius: 50%;
    --border-radius-small: 12px;
    --border-radius-medium: 20px;
    
    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'Inter', sans-serif;
    --font-size-small: 14px;
    --font-size-normal: 16px;
    --font-size-large: 20px;
    --font-size-xl: 28px;
    --font-size-xxl: 40px;
    --font-size-display: 64px;
    
    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    
    /* Transizioni */
    --transition-fast: 0.1s ease;
    --transition-normal: 0.2s ease;
    --transition-slow: 0.3s ease;
}

/* Base styles */
body {
    font-family: var(--font-family);
    background: var(--background-dark);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md);
    color: var(--text-primary);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    box-sizing: border-box;
}

/* Container principale */
.app-container {
    background: var(--background-card);
    border-radius: var(--border-radius-medium);
    box-shadow: var(--shadow-heavy);
    width: 100%;
    max-width: 400px;
    height: 600px;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    position: relative;
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
}

/* Display */
.calculator-display {
    background: var(--background-card);
    padding: var(--spacing-xl) var(--spacing-lg);
    text-align: right;
    height: 140px;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    position: relative;
}

.display-history {
    font-size: var(--font-size-large);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    min-height: 28px;
    word-wrap: break-word;
    font-weight: 400;
}

.display-current {
    font-size: var(--font-size-display);
    font-weight: 300;
    color: var(--text-primary);
    word-wrap: break-word;
    line-height: 1.1;
    letter-spacing: -0.02em;
}

/* Container calcolatrice */
.calculator-container {
    padding: var(--spacing-md);
    background: var(--background-card);
    flex: 1;
    display: flex;
    flex-direction: column;
}

/* Griglia pulsanti */
.button-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-sm);
    flex: 1;
    align-items: center;
}

/* Pulsanti calcolatrice */
.calc-btn {
    background: var(--background-button);
    border: none;
    border-radius: var(--border-radius);
    padding: 0;
    font-size: var(--font-size-xl);
    font-weight: 400;
    color: var(--text-primary);
    cursor: pointer;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    aspect-ratio: 1;
    min-height: 60px;
    max-height: 80px;
    user-select: none;
    -webkit-tap-highlight-color: transparent;
    font-family: var(--font-family);
    position: relative;
    overflow: hidden;
    width: 100%;
    height: 100%;
}

.calc-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at center, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
    opacity: 0;
    transition: var(--transition-fast);
}

.calc-btn:hover::before {
    opacity: 1;
}

.calc-btn:active {
    transform: scale(0.95);
}

/* Tipi di pulsanti */
.number-btn {
    background: var(--background-button);
    color: var(--text-primary);
    font-weight: 400;
}

.number-btn:hover {
    background: var(--background-button-hover);
}

.operator-btn {
    background: var(--background-operator);
    color: var(--text-dark);
    font-weight: 500;
}

.operator-btn:hover {
    background: var(--background-operator-hover);
}

.function-btn {
    background: var(--background-function);
    color: var(--text-dark);
    font-weight: 500;
    font-size: var(--font-size-large);
}

.function-btn:hover {
    background: var(--background-function-hover);
}

.equals-btn {
    background: var(--background-equals);
    color: var(--text-dark);
    font-weight: 500;
}

.equals-btn:hover {
    background: var(--background-equals-hover);
}

/* Pulsante zero speciale - corretto per allineamento */
.zero-btn {
    grid-column: span 2;
    border-radius: 40px;
    justify-content: flex-start;
    padding-left: 32px;
    grid-row: 5;
    grid-column: 1 / 3;
    aspect-ratio: 2.2; /* Riduce l'altezza del pulsante zero */
    min-height: 80px; /* Mantiene l'altezza minima come gli altri pulsanti */
}

/* Focus styles per accessibilità */
.calc-btn:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(255, 159, 10, 0.5);
}

/* Animazioni */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.app-container {
    animation: fadeIn var(--transition-slow);
}

@keyframes buttonPress {
    0% { transform: scale(1); }
    50% { transform: scale(0.95); }
    100% { transform: scale(1); }
}

.calc-btn:active {
    animation: buttonPress var(--transition-fast);
}

/* Responsive design - Tablet */
@media (max-width: 768px) {
    body {
        padding: var(--spacing-sm);
    }
    
    .app-container {
        max-width: 100%;
        height: 550px;
    }
    
    .calculator-display {
        height: 120px;
    }
    
    .calc-btn {
        min-height: 65px;
        max-height: 75px;
        font-size: var(--font-size-large);
    }
    
    .display-current {
        font-size: var(--font-size-xxl);
    }
    
    .display-history {
        font-size: var(--font-size-large);
    }
    
    .zero-btn {
        padding-left: 28px;
    }
}

/* Responsive design - Mobile */
@media (max-width: 480px) {
    body {
        padding: 8px;
    }
    
    .app-container {
        max-width: 100%;
        height: 500px;
        border-radius: var(--border-radius-small);
    }
    
    .calculator-display {
        height: 100px;
        padding: var(--spacing-lg) var(--spacing-md);
    }
    
    .calc-btn {
        min-height: 55px;
        max-height: 65px;
        font-size: var(--font-size-normal);
    }
    
    .display-current {
        font-size: var(--font-size-xl);
    }
    
    .display-history {
        font-size: var(--font-size-normal);
    }
    
    .zero-btn {
        padding-left: 24px;
    }
    
    .calculator-credits {
        font-size: 9px;
        bottom: 6px;
    }
}

/* Responsive design - Mobile Small */
@media (max-width: 360px) {
    body {
        padding: 6px;
    }
    
    .app-container {
        height: 450px;
    }
    
    .calculator-display {
        height: 80px;
        padding: var(--spacing-md);
    }
    
    .calc-btn {
        min-height: 50px;
        max-height: 60px;
        font-size: var(--font-size-small);
    }
    
    .display-current {
        font-size: var(--font-size-large);
    }
    
    .display-history {
        font-size: var(--font-size-small);
    }
    
    .zero-btn {
        padding-left: 20px;
    }
    
    .calculator-credits {
        font-size: 8px;
        bottom: 4px;
    }
}

/* Responsive design - Landscape */
@media (max-height: 600px) and (orientation: landscape) {
    body {
        padding: 4px;
    }
    
    .app-container {
        height: 95vh;
        max-height: 400px;
    }
    
    .calculator-display {
        height: 60px;
        padding: var(--spacing-md);
    }
    
    .calc-btn {
        min-height: 45px;
        max-height: 55px;
        font-size: var(--font-size-small);
    }
    
    .display-current {
        font-size: var(--font-size-large);
    }
    
    .display-history {
        font-size: var(--font-size-small);
    }
    
    .calculator-credits {
        font-size: 8px;
        bottom: 2px;
    }
}

/* Dark mode support (già scuro di default) */
@media (prefers-color-scheme: light) {
    :root {
        --background-dark: #f2f2f7;
        --background-card: #ffffff;
        --background-button: #f2f2f7;
        --background-button-hover: #e5e5ea;
        --text-primary: #000000;
        --text-secondary: #8e8e93;
        --text-dark: #ffffff;
    }
}

/* Credits integrati */
.calculator-credits {
    position: absolute;
    bottom: 8px;
    left: 50%;
    transform: translateX(-50%);
    color: var(--text-secondary);
    font-size: 10px;
    font-weight: 400;
    opacity: 0.7;
    pointer-events: none;
    z-index: 10;
}

.calculator-credits span {
    font-family: var(--font-family);
}

/* Supporto per dispositivi con notch */
@supports (padding: max(0px)) {
    body {
        padding-left: max(var(--spacing-md), env(safe-area-inset-left));
        padding-right: max(var(--spacing-md), env(safe-area-inset-right));
        padding-top: max(var(--spacing-md), env(safe-area-inset-top));
        padding-bottom: max(var(--spacing-md), env(safe-area-inset-bottom));
    }
    
    @media (max-width: 480px) {
        body {
            padding-left: max(8px, env(safe-area-inset-left));
            padding-right: max(8px, env(safe-area-inset-right));
            padding-top: max(8px, env(safe-area-inset-top));
            padding-bottom: max(8px, env(safe-area-inset-bottom));
        }
    }
    
    @media (max-width: 360px) {
        body {
            padding-left: max(6px, env(safe-area-inset-left));
            padding-right: max(6px, env(safe-area-inset-right));
            padding-top: max(6px, env(safe-area-inset-top));
            padding-bottom: max(6px, env(safe-area-inset-bottom));
        }
    }
}