:root {
    --bg-color: #050510;
    --panel-bg: rgba(10, 15, 30, 0.9);
    --primary-color: #00d2ff;
    --secondary-color: #ff0055;
    --text-color: #e0e0ff;
    --success-color: #00ff88;
    --danger-color: #ff3333;
    --border-color: #333355;
    --font-main: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: var(--font-main);
    overflow: hidden;
    width: 100vw;
    height: 100vh;
}

#game-root {
    position: relative;
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
}

#visuals {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
}

canvas {
    display: block;
    width: 100%;
    height: 100%;
}

#click-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%; /* Cover full screen for easy clicking */
    z-index: 1;
    cursor: crosshair;
}

#ui-layer {
    position: absolute;
    z-index: 2;
    display: flex;
    flex-direction: column;
    pointer-events: none; /* Let clicks pass through generally */
    width: 100%;
    height: 100%;
}

#top-bar {
    display: flex;
    justify-content: space-between;
    padding: 1rem;
    background: linear-gradient(to bottom, rgba(0,0,0,0.8), transparent);
    pointer-events: auto;
}

.resource-group {
    display: flex;
    flex-direction: column;
    align-items: center;
    background: rgba(0, 210, 255, 0.1);
    border: 1px solid var(--primary-color);
    border-radius: 8px;
    padding: 0.5rem 1rem;
    min-width: 120px;
    box-shadow: 0 0 10px rgba(0, 210, 255, 0.2);
    backdrop-filter: blur(5px);
}

.resource-label {
    font-size: 0.8rem;
    color: var(--primary-color);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.resource-value {
    font-size: 1.5rem;
    font-weight: bold;
    color: white;
    text-shadow: 0 0 5px var(--primary-color);
}

#interaction-area {
    margin-top: auto;
    background: var(--panel-bg);
    border-top: 2px solid var(--border-color);
    display: flex;
    flex-direction: column;
    max-height: 50vh;
    pointer-events: auto;
    backdrop-filter: blur(10px);
}

#tabs {
    display: flex;
    background: rgba(0,0,0,0.5);
}

.tab-btn {
    flex: 1;
    background: transparent;
    border: none;
    color: #8888aa;
    padding: 1rem;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.2s;
    border-bottom: 3px solid transparent;
}

.tab-btn.active {
    color: var(--primary-color);
    border-bottom: 3px solid var(--primary-color);
    background: rgba(0, 210, 255, 0.05);
}

.tab-btn:hover {
    color: white;
}

#panels {
    padding: 1rem;
    overflow-y: auto;
    flex: 1;
}

.panel {
    display: none;
    animation: fadeIn 0.3s ease;
}

.panel.active {
    display: block;
}

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

h2 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-size: 1.2rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

.upgrade-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1rem;
}

.upgrade-item {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 0.8rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.2s;
}

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

.upgrade-info {
    flex: 1;
}

.upgrade-name {
    font-weight: bold;
    color: white;
    display: block;
}

.upgrade-desc {
    font-size: 0.8rem;
    color: #aaa;
    display: block;
    margin-top: 2px;
}

.upgrade-cost {
    font-size: 0.9rem;
    color: var(--secondary-color);
    margin-top: 4px;
    display: block;
}

.btn-buy {
    background: transparent;
    border: 1px solid var(--primary-color);
    color: var(--primary-color);
    padding: 0.5rem 1rem;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.2s;
    font-weight: bold;
    margin-left: 1rem;
}

.btn-buy:hover:not(:disabled) {
    background: var(--primary-color);
    color: black;
    box-shadow: 0 0 10px var(--primary-color);
}

.btn-buy:disabled {
    border-color: #444;
    color: #666;
    cursor: not-allowed;
}

.action-btn {
    background: var(--primary-color);
    border: none;
    color: black;
    padding: 0.8rem 1.5rem;
    border-radius: 4px;
    cursor: pointer;
    font-weight: bold;
    margin-right: 1rem;
    margin-bottom: 1rem;
}

.action-btn.danger {
    background: var(--danger-color);
    color: white;
}

.settings-group {
    margin-bottom: 1.5rem;
}

.settings-group label {
    display: block;
    margin-bottom: 0.5rem;
    cursor: pointer;
}

#version-info {
    font-size: 0.8rem;
    color: #555;
    text-align: center;
    margin-top: 2rem;
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}
::-webkit-scrollbar-track {
    background: rgba(0,0,0,0.2);
}
::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
    background: var(--primary-color);
}

/* Desktop override */
@media (min-width: 768px) {
    #ui-layer {
        width: 400px;
        right: 0;
        left: auto; /* Pin to right */
        height: 100vh;
        border-left: 2px solid var(--border-color);
        background: rgba(0,0,0,0.5); /* Slight tint for sidebar area */
    }

    #interaction-area {
        height: 100%;
        max-height: none;
        margin-top: 0;
        background: var(--panel-bg);
        border-top: none;
    }

    #click-overlay {
        width: calc(100% - 400px); /* Only cover the visible canvas part */
    }
}