:root {
    --bg-primary: #0a0a0f;
    --bg-secondary: #12121a;
    --bg-card: rgba(255, 255, 255, 0.03);
    --bg-card-alt: rgba(0, 212, 255, 0.05);
    --text-primary: #f0f0f5;
    --text-secondary: #8888aa;
    --accent: #00d4ff;
    --accent-glow: rgba(0, 212, 255, 0.15);
    --accent-glow-strong: rgba(0, 212, 255, 0.3);
    --success: #00e676;
    --success-glow: rgba(0, 230, 118, 0.2);
    --danger: #ff1744;
    --danger-glow: rgba(255, 23, 68, 0.2);
    --warning: #ffab00;
    --border: rgba(255, 255, 255, 0.06);
    --border-accent: rgba(0, 212, 255, 0.2);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;
}

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

html, body {
    width: 100%;
    height: 100%;
}

body {
    font-family: 'Space Grotesk', sans-serif;
    background: linear-gradient(135deg, #0a0a0f 0%, #1a0a2e 50%, #0f0f1f 100%);
    color: var(--text-primary);
    overflow: hidden;
    -webkit-user-select: none;
    user-select: none;
    -webkit-touch-callout: none;
}

.app-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
    max-width: 375px;
    margin: 0 auto;
    background: var(--bg-primary);
    position: relative;
    overflow: hidden;
}

/* Header */
.header {
    padding: 16px;
    border-bottom: 1px solid var(--border-accent);
    background: linear-gradient(180deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
    box-shadow: 0 4px 20px var(--accent-glow);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.app-title {
    font-size: 20px;
    font-weight: 700;
    letter-spacing: -0.02em;
    background: linear-gradient(90deg, var(--accent) 0%, #00e5ff 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.header-stats {
    display: flex;
    gap: 12px;
    align-items: center;
}

.streak-badge {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 6px 12px;
    background: var(--accent-glow);
    border: 1px solid var(--border-accent);
    border-radius: var(--radius-md);
    font-size: 13px;
    font-weight: 600;
    color: var(--accent);
}

.streak-icon {
    font-size: 14px;
    animation: pulse-fire 1.5s ease-in-out infinite;
}

@keyframes pulse-fire {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.6; transform: scale(1.1); }
}

.usage-counter {
    padding: 6px 12px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    font-size: 12px;
    color: var(--text-secondary);
}

/* Main Content */
.main-content {
    flex: 1;
    overflow-y: auto;
    overflow-x: hidden;
    padding-bottom: 70px;
    scroll-behavior: smooth;
}

.screen {
    display: flex;
    flex-direction: column;
    padding: 20px;
    opacity: 1;
    animation: slideUp 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.screen.hidden {
    display: none;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Game Screen */
.game-intro {
    text-align: center;
    margin-bottom: 24px;
}

.tagline {
    font-size: 14px;
    color: var(--text-secondary);
    font-weight: 300;
    letter-spacing: 0.5px;
}

.game-area {
    display: flex;
    flex-direction: column;
    gap: 24px;
    margin-bottom: 24px;
}

.timer-display {
    display: flex;
    align-items: baseline;
    justify-content: center;
    gap: 8px;
    padding: 24px;
    background: var(--bg-card-alt);
    border: 2px solid var(--border-accent);
    border-radius: var(--radius-lg);
    animation: slideDown 0.6s cubic-bezier(0.16, 1, 0.3, 1) 0.1s both;
}

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

#timer {
    font-size: 48px;
    font-weight: 700;
    color: var(--accent);
    font-variant-numeric: tabular-nums;
}

.timer-label {
    font-size: 12px;
    color: var(--text-secondary);
    font-weight: 500;
}

.score-display {
    text-align: center;
    padding: 16px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    animation: slideDown 0.6s cubic-bezier(0.16, 1, 0.3, 1) 0.2s both;
}

.score-label {
    display: block;
    font-size: 11px;
    color: var(--text-secondary);
    font-weight: 600;
    letter-spacing: 1px;
    margin-bottom: 4px;
}

.score-value {
    display: block;
    font-size: 32px;
    font-weight: 700;
    color: var(--accent);
    font-variant-numeric: tabular-nums;
}

.number-grid {
    display: flex;
    flex-direction: column;
    gap: 16px;
    animation: slideDown 0.6s cubic-bezier(0.16, 1, 0.3, 1) 0.3s both;
}

.target-number {
    text-align: center;
    padding: 16px;
    background: linear-gradient(135deg, var(--accent-glow) 0%, var(--accent-glow-strong) 100%);
    border: 2px solid var(--accent);
    border-radius: var(--radius-lg);
    position: relative;
    overflow: hidden;
}

.target-number::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: linear-gradient(45deg, transparent 30%, rgba(255, 255, 255, 0.1) 50%, transparent 70%);
    animation: shine 3s infinite;
}

@keyframes shine {
    0% { transform: translate(-100%, -100%); }
    100% { transform: translate(100%, 100%); }
}

.target-label {
    display: block;
    font-size: 10px;
    color: var(--text-secondary);
    font-weight: 600;
    letter-spacing: 1px;
    margin-bottom: 8px;
}

.target-value {
    display: block;
    font-size: 56px;
    font-weight: 800;
    color: var(--text-primary);
    font-variant-numeric: tabular-nums;
    position: relative;
    z-index: 1;
}

.number-buttons {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
}

.number-btn {
    padding: 20px;
    background: var(--bg-card);
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: 'Space Grotesk', sans-serif;
    font-size: 24px;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
    min-height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-variant-numeric: tabular-nums;
}

.number-btn:hover:not(:disabled) {
    background: var(--accent-glow);
    border-color: var(--accent);
    transform: translateY(-2px);
    box-shadow: 0 8px 20px var(--accent-glow-strong);
}

.number-btn:active:not(:disabled) {
    transform: translateY(0) scale(0.98);
}

.number-btn.correct {
    background: var(--success-glow);
    border-color: var(--success);
    color: var(--success);
    box-shadow: 0 0 20px var(--success-glow);
}

.number-btn.wrong {
    background: var(--danger-glow);
    border-color: var(--danger);
    color: var(--danger);
    animation: shake 0.3s ease-in-out;
}

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

.number-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

.combo-display {
    text-align: center;
    padding: 12px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    font-size: 14px;
    font-weight: 600;
    color: var(--accent);
}

/* Results Screen */
.results-card {
    display: flex;
    flex-direction: column;
    gap: 24px;
    animation: slideUp 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.results-header {
    text-align: center;
}

.results-header h2 {
    font-size: 36px;
    font-weight: 800;
    letter-spacing: -0.02em;
    background: linear-gradient(90deg, var(--success) 0%, var(--accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 8px;
}

.results-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
}

.stat-item {
    display: flex;
    flex-direction: column;
    padding: 16px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    text-align: center;
}

.stat-label {
    font-size: 11px;
    color: var(--text-secondary);
    font-weight: 600;
    letter-spacing: 0.5px;
    margin-bottom: 8px;
}

.stat-value {
    font-size: 20px;
    font-weight: 700;
    color: var(--accent);
    font-variant-numeric: tabular-nums;
}

.results-actions {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

/* Premium Screen */
.premium-card {
    display: flex;
    flex-direction: column;
    gap: 24px;
    animation: slideUp 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.premium-header {
    text-align: center;
}

.premium-header h2 {
    font-size: 28px;
    font-weight: 800;
    letter-spacing: -0.02em;
    color: var(--accent);
    margin-bottom: 8px;
}

.premium-subtitle {
    font-size: 14px;
    color: var(--text-secondary);
    font-weight: 300;
}

.premium-benefits {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.benefit-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px;
    background: var(--accent-glow);
    border: 1px solid var(--border-accent);
    border-radius: var(--radius-md);
}

.benefit-icon {
    font-size: 20px;
    flex-shrink: 0;
}

.benefit-text {
    font-size: 14px;
    color: var(--text-primary);
    font-weight: 500;
}

.premium-pricing {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
}

.price-item {
    display: flex;
    flex-direction: column;
    padding: 16px;
    background: var(--bg-card);
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    text-align: center;
}

.price-label {
    font-size: 12px;
    color: var(--text-secondary);
    font-weight: 600;
    margin-bottom: 8px;
}

.price-value {
    font-size: 18px;
    font-weight: 700;
    color: var(--accent);
}

/* History Screen */
.history-container {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.history-title {
    font-size: 24px;
    font-weight: 800;
    letter-spacing: -0.02em;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.history-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.history-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    animation: slideUp 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.history-item-left {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.history-date {
    font-size: 12px;
    color: var(--text-secondary);
    font-weight: 500;
}

.history-score {
    font-size: 18px;
    font-weight: 700;
    color: var(--accent);
}

.history-combo {
    font-size: 12px;
    color: var(--text-secondary);
}

.history-empty {
    text-align: center;
    padding: 32px 16px;
    color: var(--text-secondary);
    font-size: 14px;
}

/* Buttons */
.btn {
    padding: 12px 16px;
    background: var(--bg-card);
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: 'Space Grotesk', sans-serif;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
    letter-spacing: 0.5px;
    min-height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.btn:hover {
    transform: translateY(-2px);
}

.btn:active {
    transform: translateY(0) scale(0.98);
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent) 0%, #00e5ff 100%);
    border-color: var(--accent);
    color: #000;
    font-weight: 700;
    box-shadow: 0 8px 25px var(--accent-glow);
}

.btn-primary:hover {
    box-shadow: 0 12px 35px var(--accent-glow-strong);
}

.btn-secondary {
    background: var(--accent-glow);
    border-color: var(--accent);
    color: var(--accent);
}

.btn-secondary:hover {
    background: var(--accent-glow-strong);
}

.btn-ghost {
    background: transparent;
    border-color: var(--border);
    color: var(--text-secondary);
}

.btn-ghost:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.btn-large {
    padding: 16px 24px;
    font-size: 16px;
    min-height: 52px;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

/* Bottom Navigation */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    display: flex;
    justify-content: space-around;
    padding: 8px 0;
    background: linear-gradient(180deg, transparent 0%, var(--bg-secondary) 50%);
    border-top: 1px solid var(--border-accent);
    max-width: 375px;
    margin: 0 auto;
    z-index: 100;
}

.nav-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    padding: 8px 12px;
    background: none;
    border: none;
    color: var(--text-secondary);
    font-family: 'Space Grotesk', sans-serif;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
    font-size: 12px;
    font-weight: 600;
}

.nav-btn:hover {
    color: var(--accent);
}

.nav-btn.active {
    color: var(--accent);
}

.nav-icon {
    font-size: 20px;
}

.nav-label {
    font-size: 10px;
    letter-spacing: 0.5px;
}

/* Responsive Design */
@media (max-height: 600px) {
    .header {
        padding: 12px;
    }

    .app-title {
        font-size: 16px;
    }

    .timer-display {
        padding: 16px;
    }

    #timer {
        font-size: 36px;
    }

    .number-grid {
        gap: 12px;
    }

    .number-btn {
        padding: 16px;
        font-size: 20px;
        min-height: 50px;
    }
}

/* Scrollbar styling */
.main-content::-webkit-scrollbar {
    width: 4px;
}

.main-content::-webkit-scrollbar-track {
    background: transparent;
}

.main-content::-webkit-scrollbar-thumb {
    background: var(--border);
    border-radius: 2px;
}

.main-content::-webkit-scrollbar-thumb:hover {
    background: var(--border-accent);
}

/* Grid pattern background */
.app-container::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image:
        linear-gradient(0deg, transparent 24%, rgba(0, 212, 255, 0.02) 25%, rgba(0, 212, 255, 0.02) 26%, transparent 27%, transparent 74%, rgba(0, 212, 255, 0.02) 75%, rgba(0, 212, 255, 0.02) 76%, transparent 77%, transparent),
        linear-gradient(90deg, transparent 24%, rgba(0, 212, 255, 0.02) 25%, rgba(0, 212, 255, 0.02) 26%, transparent 27%, transparent 74%, rgba(0, 212, 255, 0.02) 75%, rgba(0, 212, 255, 0.02) 76%, transparent 77%, transparent);
    background-size: 50px 50px;
    pointer-events: none;
    z-index: -1;
}

/* Animate in helper */
.animate-in {
    animation: slideUp 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}