:root {
    --bg-color: #0a0a0f;
    --card-bg: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.1);
    --primary: #00f2ff;
    --secondary: #bd00ff;
    --accent: #ff007a;
    --text: #ffffff;
    --text-dim: rgba(255, 255, 255, 0.6);
    --font-main: 'Outfit', sans-serif;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    background-color: var(--bg-color);
    color: var(--text);
    font-family: var(--font-main);
    overflow: hidden;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

#app {
    width: 100%;
    max-width: 500px;
    height: 100vh;
    position: relative;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

/* Background Glows */
.bg-glow {
    position: absolute;
    width: 300px;
    height: 300px;
    border-radius: 50%;
    filter: blur(100px);
    opacity: 0.2;
    z-index: -1;
    pointer-events: none;
}

.bg-glow-1 {
    background: var(--primary);
    top: -50px;
    left: -50px;
}

.bg-glow-2 {
    background: var(--secondary);
    bottom: -50px;
    right: -50px;
}

/* Screen Transitions */
.screen {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    padding: 40px 24px;
    display: flex;
    flex-direction: column;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: var(--transition);
}

.screen.active {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

/* Main Menu */
#menu-screen {
    justify-content: center;
    align-items: center;
    text-align: center;
}

.game-title {
    font-size: 4rem;
    font-weight: 600;
    letter-spacing: -2px;
    margin-bottom: 8px;
    background: linear-gradient(to right, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.game-title span {
    font-weight: 300;
}

.game-subtitle {
    font-size: 1.1rem;
    color: var(--text-dim);
    margin-bottom: 48px;
    letter-spacing: 2px;
    text-transform: uppercase;
}

.menu-buttons {
    display: flex;
    flex-direction: column;
    gap: 16px;
    width: 100%;
    max-width: 280px;
}

/* Buttons */
.btn {
    padding: 16px 32px;
    border-radius: 16px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    font-family: inherit;
}

.btn-primary {
    background: linear-gradient(45deg, var(--primary), #00a2ff);
    color: #000;
    box-shadow: 0 8px 24px rgba(0, 242, 255, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 32px rgba(0, 242, 255, 0.5);
}

.btn-secondary {
    background: var(--card-bg);
    color: var(--text);
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(10px);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--text-dim);
}

.btn-icon {
    background: transparent;
    border: 1px solid var(--glass-border);
    color: var(--text);
    padding: 12px;
    border-radius: 12px;
}

.btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
    transform: none !important;
}

/* Levels Screen */
.screen-header {
    display: flex;
    align-items: center;
    gap: 20px;
    margin-bottom: 32px;
}

.back-btn {
    background: var(--card-bg);
    border: 1px solid var(--glass-border);
    color: var(--text);
    width: 44px;
    height: 44px;
    border-radius: 12px;
    font-size: 1.2rem;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
}

.levels-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
    overflow-y: auto;
    padding-bottom: 40px;
}

.level-card {
    aspect-ratio: 1;
    background: var(--card-bg);
    border: 1px solid var(--glass-border);
    border-radius: 12px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    gap: 2px;
}

.level-card span {
    font-size: 1.2rem;
}

.level-card small {
    font-size: 0.7rem;
    opacity: 0.5;
    font-weight: 400;
}

.level-card:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--primary);
}

.level-card.tutorial-card {
    border-color: var(--secondary);
    background: rgba(189, 0, 255, 0.1);
}

.level-card.locked {
    opacity: 0.4;
    cursor: not-allowed;
}

/* Game Screen */
.game-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 40px;
}

.level-info {
    text-align: center;
}

.level-info span {
    display: block;
    font-size: 1.2rem;
    font-weight: 600;
}

#move-counter {
    font-size: 0.9rem;
    color: var(--text-dim);
}

#reset-btn {
    background: transparent;
    border: none;
    color: var(--text);
    font-size: 1.5rem;
    cursor: pointer;
    opacity: 0.6;
    transition: var(--transition);
}

#reset-btn:hover {
    opacity: 1;
    transform: rotate(45deg);
}

.game-container {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
}

.grid-container {
    display: grid;
    gap: 12px;
    width: 100%;
    aspect-ratio: 1;
    background: var(--card-bg);
    padding: 12px;
    border-radius: 24px;
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(20px);
}

.cell {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.8rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.1s, background 0.3s, border-color 0.3s;
    user-select: none;
}

.cell:active {
    transform: scale(0.95);
}

.cell.neighbor-hit {
    animation: cell-hit 0.3s ease-out;
}

.cell.zero {
    color: var(--text-dim);
    border-color: rgba(255, 255, 255, 0.05);
}

.cell.critical {
    color: var(--accent);
    border-color: var(--accent);
}

.game-footer {
    padding-top: 32px;
    display: flex;
    justify-content: center;
}

/* Overlay & Modals */
.overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(10px);
    z-index: 100;
    display: flex;
    justify-content: center;
    align-items: center;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
}

.overlay.active {
    opacity: 1;
    visibility: visible;
}

.modal {
    background: #15151e;
    border: 1px solid var(--glass-border);
    padding: 40px 32px;
    border-radius: 32px;
    text-align: center;
    width: 85%;
    transform: scale(0.9);
    transition: var(--transition);
}

.overlay.active .modal {
    transform: scale(1);
}

.modal h2 {
    font-size: 2rem;
    margin-bottom: 12px;
}

.modal p {
    color: var(--text-dim);
    margin-bottom: 32px;
}

.modal-buttons {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.btn-text {
    background: transparent;
    color: var(--text-dim);
    font-size: 1rem;
}

/* Animations */
@keyframes cell-hit {
    0% { transform: scale(1); background: rgba(255, 255, 255, 0.1); }
    50% { transform: scale(1.1); background: rgba(0, 242, 255, 0.2); }
    100% { transform: scale(1); background: rgba(255, 255, 255, 0.03); }
}

.win-confetti {
    position: absolute;
    pointer-events: none;
    z-index: 200;
}

.cell.pulse {
    animation: pulse-border 2s infinite;
}

@keyframes pulse-border {
    0% { border-color: var(--glass-border); }
    50% { border-color: rgba(0, 242, 255, 0.4); box-shadow: 0 0 15px rgba(0, 242, 255, 0.2); }
    100% { border-color: var(--glass-border); }
}

.shake {
    animation: shake 0.4s ease-in-out;
}

.tutorial-hint-overlay {
    position: absolute;
    bottom: 110px;
    left: 50%;
    transform: translateX(-50%) translateY(20px);
    background: rgba(189, 0, 255, 0.9);
    backdrop-filter: blur(5px);
    color: white;
    padding: 16px 24px;
    border-radius: 16px;
    font-size: 1rem;
    font-weight: 600;
    text-align: center;
    box-shadow: 0 12px 32px rgba(189, 0, 255, 0.5);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    z-index: 50;
    width: 90%;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.tutorial-hint-overlay.active {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(0);
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-8px); }
    50% { transform: translateX(8px); }
    75% { transform: translateX(-4px); }
}

/* Responsive fixes */
@media (max-width: 400px) {
    .grid-container {
        gap: 8px;
        padding: 8px;
    }
    .cell {
        border-radius: 12px;
        font-size: 1.4rem;
    }
}