/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Color Variables */
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --success-color: #27ae60;
    --danger-color: #e74c3c;
    --warning-color: #f39c12;
    --light-gray: #ecf0f1;
    --medium-gray: #95a5a6;
    --dark-gray: #34495e;
    --white: #ffffff;
    --black: #2c3e50;
    
    /* Cell Colors */
    --cell-hidden: #bdc3c7;
    --cell-revealed: #ecf0f1;
    --cell-flagged: #e74c3c;
    --cell-mine: #c0392b;
    --cell-border: #95a5a6;
    
    /* Number Colors */
    --number-1: #3498db;
    --number-2: #27ae60;
    --number-3: #e74c3c;
    --number-4: #8e44ad;
    --number-5: #f39c12;
    --number-6: #e67e22;
    --number-7: #2c3e50;
    --number-8: #95a5a6;
    
    /* Shadows */
    --shadow-light: 0 2px 4px rgba(0,0,0,0.1);
    --shadow-medium: 0 4px 8px rgba(0,0,0,0.15);
    --shadow-heavy: 0 8px 16px rgba(0,0,0,0.2);
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-medium: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    /* Safe Areas */
    --safe-area-top: env(safe-area-inset-top);
    --safe-area-bottom: env(safe-area-inset-bottom);
    --safe-area-left: env(safe-area-inset-left);
    --safe-area-right: env(safe-area-inset-right);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    min-height: 100dvh; /* Dynamic viewport height for mobile browsers */
    display: flex;
    align-items: center;
    justify-content: center;
    padding: max(var(--safe-area-top), 8px) 0 max(var(--safe-area-bottom), 8px) 0;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    user-select: none;
}

/* Container */
.container {
    width: 100%;
    margin: 0;
    padding: 20px 0;
    background: #2a2a2a;
    border-radius: 0;
    box-shadow: var(--shadow-heavy);
    min-height: calc(100vh - 40px);
    min-height: calc(100dvh - 40px); /* Dynamic viewport height */
    display: flex;
    flex-direction: column;
    position: relative;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

/* Header */
.game-header {
    text-align: center;
    margin-bottom: 20px;
}

.game-title {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    margin: 0;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.1);
}

/* Game Controls */
.game-controls {
    margin-bottom: 20px;
}

.stats-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    min-width: 60px;
}

.stat-label {
    font-size: 0.8rem;
    color: var(--medium-gray);
    margin-bottom: 2px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.mine-counter, .timer {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    font-family: 'Courier New', monospace;
    background: var(--light-gray);
    padding: 8px 12px;
    border-radius: 8px;
    min-width: 50px;
    text-align: center;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.1);
}

.timer-container {
    display: flex;
    align-items: center;
    gap: 8px;
}

.new-game-btn {
    background: var(--light-gray);
    border: 3px solid var(--medium-gray);
    border-radius: 50%;
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-fast);
    box-shadow: var(--shadow-medium);
}

.new-game-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-heavy);
}

.new-game-btn:active {
    transform: translateY(0);
    box-shadow: var(--shadow-light);
}

.game-face {
    font-size: 1.8rem;
    display: block;
}

.controls-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 10px;
}

.difficulty-selector {
    display: flex;
    gap: 5px;
    flex: 1;
}

.difficulty-btn {
    flex: 1;
    padding: 10px 8px;
    border: 2px solid var(--medium-gray);
    background: var(--white);
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--primary-color);
    cursor: pointer;
    transition: all var(--transition-fast);
    min-height: 44px;
}

.difficulty-btn:hover {
    background: var(--light-gray);
}

.difficulty-btn.active {
    background: var(--secondary-color);
    color: var(--white);
    border-color: var(--secondary-color);
}

.flag-mode-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 15px;
    border: 2px solid var(--medium-gray);
    background: var(--white);
    border-radius: 8px;
    cursor: pointer;
    transition: all var(--transition-fast);
    min-height: 44px;
    white-space: nowrap;
}

.flag-mode-btn:hover {
    background: var(--light-gray);
}

.flag-mode-btn.active {
    background: var(--danger-color);
    color: var(--white);
    border-color: var(--danger-color);
}

.flag-icon {
    font-size: 1.2rem;
}

.flag-mode-text {
    font-size: 0.9rem;
    font-weight: 600;
}

/* Game Board */
.game-board-container {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
}

.game-board {
    display: grid;
    grid-template-columns: repeat(var(--grid-cols), 1fr);
    grid-template-rows: repeat(var(--grid-rows), 1fr);
    gap: 2px;
    padding: 0;
    background: var(--cell-border);
    border-radius: 0;
    box-shadow: var(--shadow-medium);
    max-width: 100%;
    max-height: 70vh;
    aspect-ratio: var(--grid-cols) / var(--grid-rows);
}

/* Cell Styles */
.cell {
    background: var(--cell-hidden);
    border: 2px solid var(--cell-border);
    border-radius: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 1rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    min-width: 44px;
    min-height: 44px;
    user-select: none;
    -webkit-user-select: none;
    -webkit-touch-callout: none;
    position: relative;
}

.cell.touched {
    transform: scale(0.95);
    background: var(--medium-gray);
    transition: all 0.1s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Enhanced touch feedback for high-resolution devices like iPhone 15 Pro */
@media screen and (-webkit-min-device-pixel-ratio: 2) {
    .cell.touched {
        transform: scale(0.92);
        background: rgba(0,0,0,0.15);
        box-shadow: inset 0 3px 6px rgba(0,0,0,0.25);
        transition: all 0.08s cubic-bezier(0.4, 0, 0.2, 1);
    }
}

.cell.hidden {
    background: linear-gradient(145deg, #d6d6d6, #b0b0b0);
    box-shadow: 
        inset -2px -2px 4px rgba(0,0,0,0.2),
        inset 2px 2px 4px rgba(255,255,255,0.8);
}

.cell.hidden:hover {
    background: linear-gradient(145deg, #e0e0e0, #c0c0c0);
}

.cell.revealed {
    background: var(--cell-revealed);
    border-color: var(--medium-gray);
    box-shadow: inset 1px 1px 2px rgba(0,0,0,0.1);
}

.cell.flagged {
    background: linear-gradient(145deg, #ff6b6b, #e74c3c);
    color: var(--white);
    animation: flagPulse 0.3s ease;
}

.cell.mine {
    background: linear-gradient(145deg, #ff4757, #c44569);
    color: var(--white);
    animation: explode 0.5s ease;
}

/* Number Colors */
.cell.number-1 { color: var(--number-1); }
.cell.number-2 { color: var(--number-2); }
.cell.number-3 { color: var(--number-3); }
.cell.number-4 { color: var(--number-4); }
.cell.number-5 { color: var(--number-5); }
.cell.number-6 { color: var(--number-6); }
.cell.number-7 { color: var(--number-7); }
.cell.number-8 { color: var(--number-8); }

/* Game Message */
.game-message {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0,0,0,0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-medium);
    z-index: 1000;
}

.game-message.show {
    opacity: 1;
    visibility: visible;
}

.message-content {
    background: var(--white);
    padding: 40px 30px;
    border-radius: 20px;
    text-align: center;
    box-shadow: var(--shadow-heavy);
    max-width: 90%;
    animation: messageSlideIn 0.3s ease;
}

.message-text {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 20px;
    display: block;
}

.message-btn {
    background: var(--secondary-color);
    color: var(--white);
    border: none;
    padding: 12px 24px;
    border-radius: 25px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
    min-height: 44px;
}

.message-btn:hover {
    background: #2980b9;
    transform: translateY(-2px);
    box-shadow: var(--shadow-medium);
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0,0,0,0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-medium);
    z-index: 1000;
    padding: 20px;
}

.modal.show {
    opacity: 1;
    visibility: visible;
}

.modal-content {
    background: var(--white);
    border-radius: 15px;
    max-width: 500px;
    width: 100%;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: var(--shadow-heavy);
    animation: modalSlideIn 0.3s ease;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 25px;
    border-bottom: 1px solid var(--light-gray);
}

.modal-header h2 {
    margin: 0;
    color: var(--primary-color);
    font-size: 1.5rem;
}

.modal-close {
    background: none;
    border: none;
    font-size: 2rem;
    cursor: pointer;
    color: var(--medium-gray);
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: all var(--transition-fast);
}

.modal-close:hover {
    background: var(--light-gray);
    color: var(--primary-color);
}

.modal-body {
    padding: 25px;
}

.modal-body h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 1.2rem;
}

.modal-body ul {
    margin-bottom: 20px;
    padding-left: 20px;
}

.modal-body li {
    margin-bottom: 8px;
    line-height: 1.5;
}

.modal-body p {
    line-height: 1.6;
    color: var(--dark-gray);
}

/* Help Button */
.help-btn {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--secondary-color);
    color: var(--white);
    border: none;
    font-size: 0.9rem;
    font-weight: bold;
    cursor: pointer;
    box-shadow: var(--shadow-light);
    transition: all var(--transition-fast);
    flex-shrink: 0;
}

.help-btn:hover {
    background: #2980b9;
    transform: translateY(-1px);
    box-shadow: var(--shadow-medium);
}

/* Version Info */
.version-info {
    position: fixed;
    bottom: 10px;
    left: 10px;
    display: flex;
    flex-direction: column;
    font-size: 0.7rem;
    color: var(--medium-gray);
    opacity: 0.7;
    z-index: 50;
    pointer-events: none;
    user-select: none;
}

.version-text {
    font-weight: 600;
    margin-bottom: 2px;
}

.build-date {
    font-size: 0.65rem;
    opacity: 0.8;
}

/* Animations */
@keyframes flagPulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.1); }
    100% { transform: scale(1); }
}

@keyframes explode {
    0% { transform: scale(1); }
    50% { transform: scale(1.2); }
    100% { transform: scale(1); }
}

@keyframes messageSlideIn {
    from {
        transform: translateY(-50px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

@keyframes modalSlideIn {
    from {
        transform: scale(0.8);
        opacity: 0;
    }
    to {
        transform: scale(1);
        opacity: 1;
    }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus styles for accessibility */
button:focus,
.cell:focus {
    outline: 3px solid var(--secondary-color);
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --cell-hidden: #ffffff;
        --cell-revealed: #f0f0f0;
        --cell-border: #000000;
    }
    
    .cell {
        border-width: 3px;
    }
}