:root {
    --bg-dark: #0f172a;
    --panel-bg: rgba(15, 23, 42, 0.85);
    --panel-border: rgba(56, 189, 248, 0.3);
    --panel-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
    
    --accent-blue: #38bdf8;
    --accent-glow: 0 0 10px rgba(56, 189, 248, 0.6);
    --accent-green: #22c55e;
    --accent-red: #ef4444;
    --accent-yellow: #eab308;
    
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    
    --font-ui: 'Inter', sans-serif;
    --font-mono: 'Share Tech Mono', monospace;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    user-select: none;
    -webkit-user-drag: none;
}

body, html {
    width: 100%;
    height: 100%;
    overflow: hidden;
    background-color: var(--bg-dark);
    font-family: var(--font-ui);
    color: var(--text-main);
    touch-action: none; /* Prevent scroll on touch devices */
}

/* Background Image Layer */
#game-background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url('../assets/images/background.png');
    background-size: cover;
    background-position: center bottom;
    z-index: 0;
    filter: brightness(0.6) contrast(1.1); /* Darken slightly to make game pop */
}

/* Canvas */
#game-canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
    cursor: crosshair;
}

/* UI Layer */
#ui-layer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 10;
    pointer-events: none; /* Let clicks pass through empty space */
}

.hidden {
    display: none !important;
}

.pane-3d {
    background: var(--panel-bg);
    border: 1px solid var(--panel-border);
    box-shadow: var(--panel-shadow), inset 0 1px 1px rgba(255,255,255,0.1);
    backdrop-filter: blur(8px);
    border-radius: 12px;
    pointer-events: auto;
}

/* Top Bar */
.top-bar {
    position: absolute;
    top: 20px;
    left: 20px;
    right: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 15px;
}

.level-info {
    padding: 10px 20px;
    font-family: var(--font-mono);
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--accent-blue);
    text-shadow: var(--accent-glow);
    letter-spacing: 2px;
}

.budget-info {
    flex: 1;
    max-width: 400px;
    padding: 10px 20px;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 10px;
}

.budget-info .label {
    font-size: 0.9rem;
    color: var(--text-muted);
}

#budget-text {
    font-family: var(--font-mono);
    font-size: 1.5rem;
    font-weight: bold;
    flex-grow: 1;
    text-align: right;
}

.budget-bar {
    width: 100%;
    height: 8px;
    background: #1e293b;
    border-radius: 4px;
    overflow: hidden;
    margin-top: 5px;
}

#budget-fill {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, var(--accent-green), var(--accent-yellow));
    transition: width 0.3s ease, background 0.3s ease;
}

.right-controls {
    display: flex;
    gap: 10px;
    pointer-events: auto;
}

.btn-circular {
    width: 45px;
    height: 45px;
    border-radius: 50%;
    background: var(--panel-bg);
    border: 1px solid var(--panel-border);
    color: white;
    font-size: 1.2rem;
    cursor: pointer;
    box-shadow: 0 4px 10px rgba(0,0,0,0.3);
    transition: all 0.2s;
}

.btn-circular:hover {
    background: rgba(56, 189, 248, 0.2);
    box-shadow: var(--accent-glow);
    transform: translateY(-2px);
}

/* Material Panel (Left Bottom) */
.material-panel {
    position: absolute;
    bottom: 20px;
    left: 20px;
    display: flex;
    flex-direction: column;
    padding: 15px;
    gap: 10px;
    min-width: 220px;
}

.panel-title {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-muted);
    letter-spacing: 1px;
    margin-bottom: 5px;
}

.mat-btn {
    display: flex;
    align-items: center;
    gap: 15px;
    background: rgba(30, 41, 59, 0.6);
    border: 1px solid transparent;
    padding: 10px;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
    text-align: left;
    color: var(--text-main);
}

.mat-btn:hover {
    background: rgba(30, 41, 59, 0.9);
}

.mat-btn.active {
    background: rgba(56, 189, 248, 0.15);
    border-color: var(--accent-blue);
    box-shadow: inset 0 0 15px rgba(56, 189, 248, 0.1);
}

.mat-icon {
    width: 40px;
    height: 8px;
    border-radius: 2px;
}

.road-icon { background: #475569; border-top: 2px dashed #eab308; }
.wood-icon { background: #b45309; }
.steel-icon { background: linear-gradient(90deg, #94a3b8, #e2e8f0, #94a3b8); height: 12px; }
.rope-icon { background: #d97706; height: 4px; border-radius: 2px; border-bottom: 1px dashed #78350f; }

.mat-details {
    display: flex;
    flex-direction: column;
}

.mat-name {
    font-weight: 600;
    font-size: 1rem;
}

.mat-cost {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--accent-green);
}

/* Action Tools (Right Bottom) */
.action-panel {
    position: absolute;
    bottom: 20px;
    right: 20px;
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 15px;
    pointer-events: auto;
}

.tool-group {
    display: flex;
    gap: 10px;
    padding: 10px;
}

.tool-btn {
    background: transparent;
    border: none;
    color: #cbd5e1;
    font-size: 1.5rem;
    width: 40px;
    height: 40px;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    justify-content: center;
    align-items: center;
}

.tool-btn:hover {
    background: rgba(255,255,255,0.1);
}

.tool-btn.active-tool {
    background: rgba(239, 68, 68, 0.2);
    color: var(--accent-red);
}

.tool-btn.danger:hover {
    color: var(--accent-red);
    text-shadow: 0 0 10px rgba(239, 68, 68, 0.8);
}

/* 3D Play Button */
.pane-3d-play {
    background: linear-gradient(145deg, #16a34a, #15803d);
    border: none;
    border-bottom: 6px solid #14532d;
    border-radius: 12px;
    padding: 15px 40px;
    color: white;
    font-size: 1.5rem;
    font-weight: 800;
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
    box-shadow: 0 10px 20px rgba(0,0,0,0.4);
    transition: all 0.1s;
    letter-spacing: 2px;
}

.pane-3d-play:active, .pane-3d-play.pressing {
    transform: translateY(4px);
    border-bottom-width: 2px;
    box-shadow: 0 5px 10px rgba(0,0,0,0.4);
}

/* Sim Overlay Layer */
#sim-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 15;
    pointer-events: none;
}

.sim-top {
    position: absolute;
    top: 20px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 15px 30px;
    border-color: rgba(234, 179, 8, 0.5);
    background: rgba(15, 23, 42, 0.9);
}

.sim-status {
    color: var(--accent-yellow);
    font-weight: bold;
    letter-spacing: 3px;
    animation: flash 1s infinite alternate;
}

#stress-indicator {
    font-family: var(--font-mono);
    font-size: 1.2rem;
    margin-top: 5px;
}

#max-stress-val {
    color: var(--accent-green);
    font-weight: bold;
}

.pane-3d-stop {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    background: linear-gradient(145deg, #dc2626, #b91c1c);
    border: none;
    border-bottom: 6px solid #7f1d1d;
    border-radius: 12px;
    padding: 15px 40px;
    color: white;
    font-size: 1.2rem;
    font-weight: 800;
    cursor: pointer;
    box-shadow: 0 10px 20px rgba(0,0,0,0.4);
    transition: all 0.1s;
    pointer-events: auto;
}
.pane-3d-stop:active {
    transform: translateX(-50%) translateY(4px);
    border-bottom-width: 2px;
}

@keyframes flash {
    0% { opacity: 0.7; }
    100% { opacity: 1; text-shadow: 0 0 10px var(--accent-yellow); }
}

/* Full Screen Overlays (Guide, Result) */
.overlay-screen {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.75);
    backdrop-filter: blur(10px);
    z-index: 100;
    display: flex;
    justify-content: center;
    align-items: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s;
}

.overlay-screen.active {
    opacity: 1;
    pointer-events: auto;
}

.window-3d {
    background: linear-gradient(180deg, #1e293b 0%, #0f172a 100%);
    border: 1px solid var(--panel-border);
    box-shadow: 0 20px 50px rgba(0,0,0,0.8), inset 0 2px 2px rgba(255,255,255,0.1);
    border-radius: 16px;
    width: 90%;
    max-width: 600px;
    overflow: hidden;
    transform: scale(0.9);
    transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.overlay-screen.active .window-3d {
    transform: scale(1);
}

.intro-thumbnail {
    width: 100%;
    height: 250px;
    object-fit: cover;
    border-bottom: 2px solid var(--panel-border);
}

.window-content {
    padding: 40px;
    text-align: center;
}

.window-content h1 {
    font-size: 2.2rem;
    color: white;
    margin-bottom: 5px;
    text-shadow: 0 2px 5px rgba(0,0,0,0.5);
}

.subtitle {
    color: var(--accent-blue);
    font-family: var(--font-mono);
    letter-spacing: 2px;
    margin-bottom: 30px;
}

.instructions {
    text-align: left;
    margin-bottom: 30px;
    background: rgba(0,0,0,0.3);
    padding: 20px;
    border-radius: 8px;
}

.inst-item {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 15px;
}
.inst-item:last-child { margin-bottom: 0; }

.inst-icon {
    font-size: 1.8rem;
    background: rgba(255,255,255,0.05);
    width: 50px;
    height: 50px;
    display: flex;
    justify-content: center;
    align-items: center;
    border-radius: 10px;
}

.primary-btn {
    background: linear-gradient(145deg, #0284c7, #0369a1);
    border: none;
    border-bottom: 4px solid #075985;
    padding: 15px 30px;
    color: white;
    font-size: 1.2rem;
    font-weight: bold;
    border-radius: 8px;
    cursor: pointer;
    box-shadow: 0 5px 15px rgba(0,0,0,0.4);
    transition: all 0.1s;
}

.primary-btn:active {
    transform: translateY(4px);
    border-bottom-width: 0px;
    margin-bottom: 4px;
}

.secondary-btn {
    background: transparent;
    border: 2px solid var(--text-muted);
    padding: 15px 30px;
    color: var(--text-main);
    font-size: 1.2rem;
    font-weight: bold;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
}
.secondary-btn:hover { background: rgba(255,255,255,0.1); margin-top:0;}

.pulse {
    animation: pulseGlow 2s infinite;
}

@keyframes pulseGlow {
    0% { box-shadow: 0 0 0 0 rgba(56, 189, 248, 0.7); }
    70% { box-shadow: 0 0 0 15px rgba(56, 189, 248, 0); }
    100% { box-shadow: 0 0 0 0 rgba(56, 189, 248, 0); }
}

.result-stats {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin: 30px 0;
    text-align: left;
}
.stat {
    display: flex;
    justify-content: space-between;
    font-size: 1.2rem;
    border-bottom: 1px solid rgba(255,255,255,0.1);
    padding-bottom: 5px;
}
.stat span:last-child {
    font-family: var(--font-mono);
    font-weight: bold;
    color: var(--accent-blue);
}
.result-actions {
    display: flex;
    justify-content: center;
    gap: 20px;
}

/* Responsiveness */
@media (max-width: 768px) {
    .top-bar { flex-wrap: wrap; gap: 5px; }
    .level-info { padding: 5px 10px; font-size: 1.2rem; }
    .budget-info { order: 3; width: 100%; max-width: none; padding: 5px 10px; }
    
    .panel-title { display: none; }
    .material-panel { 
        bottom: 25px; 
        left: 5%; 
        width: 90%;
        flex-direction: row; 
        justify-content: space-between;
        align-items: center;
        padding: 5px;
        height: auto;
        border-radius: 12px;
        z-index: 10;
        background: rgba(15, 23, 42, 0.95);
        box-shadow: 0 10px 30px rgba(0,0,0,0.8);
    }
    .material-panel::-webkit-scrollbar { display: none; }
    .material-panel { -ms-overflow-style: none; scrollbar-width: none; }
    
    .mat-details { display: flex; text-align: center; } 
    .mat-btn { 
        padding: 8px 4px; 
        height: auto; 
        flex: 1; 
        margin: 0 4px;
        display: flex;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 6px;
    }
    .mat-name { font-size: 0.75rem; }
    .mat-cost { font-size: 0.65rem; }
    .mat-icon { width: 35px; margin: 0; }

    .action-panel {
        bottom: 125px;
        right: 15px;
        gap: 10px;
    }

    .pane-3d-play { padding: 10px 20px; font-size: 1.1rem; border-radius: 8px;}
    
    .window-content { padding: 20px; }
    h1 { font-size: 1.6rem; }
    .intro-thumbnail { height: 150px; }
    .result-actions { flex-direction: column; }
}