:root {
    --primary-color: #0f766e;
    --secondary-color: #22d3ee;
    --accent-color: #a3ff12;
    --text-primary: #f8fafc;
    --text-secondary: #cbd5f5;
    --bg-primary: #050b1a;
    --bg-secondary: #0f172a;
    --bg-card: #16233d;
    --border-color: #223352;
    --shadow-light: rgba(34, 211, 238, 0.12);
    --gradient-primary: linear-gradient(140deg, #0f172a 0%, #0f766e 45%, #22d3ee 100%);
    --border-radius: 16px;
    --border-radius-small: 10px;
    --transition-fast: 0.18s ease;
}

[data-theme="light"] {
    --text-primary: #0f172a;
    --text-secondary: #1f2937;
    --bg-primary: #f1f5f9;
    --bg-secondary: #e2e8f0;
    --bg-card: #f8fafc;
    --border-color: #cbd5e1;
    --shadow-light: rgba(15, 118, 110, 0.08);
}

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

body {
    font-family: 'Inter', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    transition: background-color var(--transition-fast);
}

.top-nav {
    background: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 100;
    gap: 1rem;
}

.app-title {
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    flex: 1;
    text-align: center;
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.6rem 1rem;
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-small);
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.95rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    white-space: nowrap;
    flex-shrink: 0;
}

.nav-btn:hover {
    background: var(--gradient-primary);
    color: white;
    transform: translateY(-2px);
}

.nav-btn .icon { font-size: 1.25rem; }

.main-content {
    max-width: 1000px;
    margin: 0 auto;
    padding: 2rem;
}

.info-panel {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 2rem;
    padding: 1.5rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.stat {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.stat .label {
    font-size: 1rem;
    color: var(--text-secondary);
}

.stat .value {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--accent-color);
}

.controls {
    display: flex;
    gap: 1rem;
}

.action-btn, .reset-btn {
    padding: 0.8rem 1.5rem;
    color: white;
    border: none;
    border-radius: var(--border-radius-small);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.action-btn {
    background: var(--gradient-primary);
}

.reset-btn {
    background: #dc2626;
}

.action-btn:hover, .reset-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px var(--shadow-light);
}

.game-container {
    display: flex;
    flex-direction: column;
    gap: 2rem;
    align-items: center;
}

.grid {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 8px;
    padding: 1.5rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
}

.cell {
    width: 80px;
    height: 80px;
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius-small);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
}

.cell:hover {
    background: var(--primary-color);
    transform: scale(1.05);
}

.cell.start {
    background: var(--primary-color);
    border-color: var(--accent-color);
}

.cell.has-apple {
    background: rgba(220, 38, 38, 0.2);
}

.cell.path {
    background: rgba(34, 211, 238, 0.3);
    animation: pulse 1s ease-in-out infinite;
}

.cell .step-number {
    position: absolute;
    top: 5px;
    left: 5px;
    font-size: 0.8rem;
    color: var(--accent-color);
    font-weight: 700;
}

@keyframes pulse {
    0%, 100% { opacity: 0.6; }
    50% { opacity: 1; }
}

.path-info {
    padding: 1.5rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    min-height: 80px;
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    color: var(--text-secondary);
}

.instructions {
    margin-top: 2rem;
    padding: 1.5rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
}

.instructions h3 {
    color: var(--secondary-color);
    margin-bottom: 1rem;
}

.instructions ul {
    list-style: none;
    padding: 0;
}

.instructions li {
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
    color: var(--text-secondary);
}

.instructions li:before {
    content: "▸";
    position: absolute;
    left: 0;
    color: var(--accent-color);
}

@media (max-width: 768px) {
    .top-nav { padding: 0.75rem 1rem; }
    .app-title { font-size: 1.25rem; }
    .nav-btn span:not(.icon) { display: none; }
    .main-content { padding: 1rem; }
    .info-panel { flex-direction: column; }
    .cell { width: 60px; height: 60px; font-size: 2rem; }
}