:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    --border-color: #e2e8f0;
    --border-hover: #cbd5e1;
    
    --tile-empty: #ffffff;
    --tile-absent: #787c7e;
    --tile-present: #c9b458;
    --tile-correct: #6aaa64;
    --tile-border: #d3d6da;
    
    --primary-color: #6366f1;
    --primary-hover: #5048e5;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 350ms ease;
}

[data-theme="dark"] {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --border-color: #475569;
    --border-hover: #64748b;
    
    --tile-empty: #334155;
    --tile-border: #475569;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    transition: background-color var(--transition-normal), color var(--transition-normal);
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-md);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.main-content {
    flex: 1;
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-2xl);
    margin: var(--spacing-xl) 0;
}

@media (min-width: 768px) {
    .main-content {
        grid-template-columns: 1fr 1fr;
        align-items: start;
    }
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-lg) 0;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: var(--spacing-xl);
}

.header-content {
    text-align: left;
}

.title {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.emoji {
    font-size: 2rem;
}

.subtitle {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    font-weight: 400;
}

.header-actions {
    display: flex;
    gap: var(--spacing-sm);
}

.theme-toggle,
.help-btn {
    width: 40px;
    height: 40px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-secondary);
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-lg);
    font-weight: 600;
    transition: all var(--transition-fast);
}

.theme-toggle:hover,
.help-btn:hover {
    border-color: var(--border-hover);
    background: var(--bg-tertiary);
    transform: translateY(-1px);
}

.game-section,
.solver-section {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
}

.section-title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-lg);
    text-align: center;
}

.game-board-container {
    max-width: 350px;
    margin: 0 auto;
}

.game-board {
    display: grid;
    grid-template-rows: repeat(6, 1fr);
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xl);
    padding: var(--spacing-md);
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.game-row {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: var(--spacing-sm);
    transition: all var(--transition-normal);
}

.game-row.current-row {
    transform: scale(1.02);
}

.game-row.completed-row {
    opacity: 0.8;
}

.game-tile {
    width: 100%;
    aspect-ratio: 1;
    border: 2px solid var(--tile-border);
    border-radius: var(--radius-sm);
    background: var(--tile-empty);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-xl);
    font-weight: 700;
    text-transform: uppercase;
    cursor: pointer;
    transition: all var(--transition-fast);
    user-select: none;
}

.game-tile:hover {
    border-color: var(--border-hover);
    transform: scale(1.02);
}

.game-tile.filled {
    border-color: var(--text-muted);
    color: var(--text-primary);
}

.game-tile.absent {
    background: var(--tile-absent);
    border-color: var(--tile-absent);
    color: white;
}

.game-tile.present {
    background: var(--tile-present);
    border-color: var(--tile-present);
    color: white;
}

.game-tile.correct {
    background: var(--tile-correct);
    border-color: var(--tile-correct);
    color: white;
}

.game-tile.focused {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.2);
    transform: scale(1.02);
}

.game-tile:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.2);
}

.keyboard-container {
    margin-top: var(--spacing-lg);
}

.keyboard {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    align-items: center;
}

.keyboard-row {
    display: flex;
    gap: var(--spacing-xs);
}

.key {
    min-width: 32px;
    height: 40px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    background: var(--bg-tertiary);
    color: var(--text-primary);
    font-size: var(--font-size-sm);
    font-weight: 600;
    text-transform: uppercase;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
    user-select: none;
}

.key.wide {
    min-width: 60px;
    font-size: var(--font-size-xs);
    text-transform: none;
}

.key:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-1px);
}

.key.absent {
    background: var(--tile-absent);
    border-color: var(--tile-absent);
    color: white;
}

.key.present {
    background: var(--tile-present);
    border-color: var(--tile-present);
    color: white;
}

.key.correct {
    background: var(--tile-correct);
    border-color: var(--tile-correct);
    color: white;
}

.solver-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.analyze-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: var(--font-size-base);
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    transition: all var(--transition-fast);
    box-shadow: var(--shadow-sm);
}

.analyze-btn:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-icon {
    font-size: var(--font-size-lg);
}

.suggestions-panel {
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    padding: var(--spacing-xl);
    border: 1px solid var(--border-color);
    min-height: 300px;
}

.empty-state {
    text-align: center;
    color: var(--text-secondary);
}

.empty-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
}

.empty-state h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.empty-state p {
    font-size: var(--font-size-base);
    line-height: 1.6;
    max-width: 300px;
    margin: 0 auto;
}

.footer {
    text-align: center;
    padding: var(--spacing-xl) 0 var(--spacing-lg);
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
    margin-top: auto;
}

.footer p {
    margin-bottom: var(--spacing-xs);
}

.footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: color var(--transition-fast);
}

.footer a:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: var(--spacing-md);
}

.modal-overlay.active {
    display: flex;
}

.modal {
    background: var(--bg-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    max-width: 500px;
    width: 100%;
    max-height: 80vh;
    overflow-y: auto;
    border: 1px solid var(--border-color);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--text-primary);
}

.modal-close {
    background: none;
    border: none;
    font-size: var(--font-size-2xl);
    cursor: pointer;
    color: var(--text-secondary);
    padding: 0;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.modal-close:hover {
    background: var(--bg-secondary);
    color: var(--text-primary);
}

.modal-content {
    padding: var(--spacing-lg);
}

.help-step {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    align-items: flex-start;
}

.help-step:last-child {
    margin-bottom: 0;
}

.step-number {
    background: var(--primary-color);
    color: white;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: var(--font-size-sm);
    flex-shrink: 0;
}

.step-content h4 {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.step-content p {
    color: var(--text-secondary);
    font-size: var(--font-size-base);
    line-height: 1.5;
}

@media (max-width: 767px) {
    .container {
        padding: var(--spacing-sm);
    }
    
    .header {
        flex-direction: column;
        gap: var(--spacing-md);
        text-align: center;
    }
    
    .header-content {
        text-align: center;
    }
    
    .title {
        font-size: var(--font-size-2xl);
        justify-content: center;
    }
    
    .subtitle {
        font-size: var(--font-size-base);
    }
    
    .main-content {
        gap: var(--spacing-xl);
        margin: var(--spacing-lg) 0;
    }
    
    .game-section,
    .solver-section {
        padding: var(--spacing-lg);
    }
    
    .solver-header {
        flex-direction: column;
        align-items: stretch;
    }
    
    .analyze-btn {
        justify-content: center;
    }
    
    .game-board {
        padding: var(--spacing-sm);
    }
    
    .game-tile {
        font-size: var(--font-size-lg);
    }
    
    .key {
        min-width: 28px;
        height: 36px;
        font-size: var(--font-size-xs);
    }
    
    .key.wide {
        min-width: 50px;
    }
}

@media (max-width: 480px) {
    .title {
        font-size: var(--font-size-xl);
    }
    
    .emoji {
        font-size: 1.5rem;
    }
    
    .section-title {
        font-size: var(--font-size-lg);
    }
    
    .game-tile {
        font-size: var(--font-size-base);
    }
    
    .key {
        min-width: 24px;
        height: 32px;
    }
    
    .key.wide {
        min-width: 45px;
    }
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

.fade-in {
    animation: fadeIn var(--transition-normal) ease-out;
}

.slide-in {
    animation: slideIn var(--transition-normal) ease-out;
}

.hidden {
    display: none !important;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.temp-message {
    padding: var(--spacing-sm) var(--spacing-md);
    margin: var(--spacing-sm) 0;
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: 500;
    text-align: center;
    animation: slideIn 0.3s ease-out;
}

.temp-message-info {
    background: rgba(99, 102, 241, 0.1);
    color: var(--primary-color);
    border: 1px solid rgba(99, 102, 241, 0.3);
}

.temp-message-success {
    background: rgba(16, 185, 129, 0.1);
    color: var(--success-color);
    border: 1px solid rgba(16, 185, 129, 0.3);
}

.temp-message-warning {
    background: rgba(245, 158, 11, 0.1);
    color: var(--warning-color);
    border: 1px solid rgba(245, 158, 11, 0.3);
}

.temp-message-error {
    background: rgba(239, 68, 68, 0.1);
    color: var(--error-color);
    border: 1px solid rgba(239, 68, 68, 0.3);
}