/* style.css */
:root {
    --bg: #0a0a0b;
    --panel: #121214;
    --border: #2a2a2e;
    --accent: #3b82f6;
    --accent-hover: #60a5fa;
    --text-main: #ffffff;
    --text-dim: #a1a1aa;
    --card-bg: #1c1c1f;
}

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

body {
    background-color: var(--bg);
    color: var(--text-main);
    font-family: 'Inter', sans-serif;
    overflow: hidden;
    height: 100vh;
}

#app-container {
    display: flex;
    width: 100vw;
    height: 100vh;
}

/* 3D Viewport Area */
#viewport {
    flex-grow: 1;
    position: relative;
    background: radial-gradient(circle at center, #1e1e20 0%, #050505 100%);
    cursor: grab;
}

#viewport:active { cursor: grabbing; }

/* Sidebar Styling */
#sidebar {
    width: 340px;
    background: var(--panel);
    border-left: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    padding: 32px 24px;
    z-index: 100;
    box-shadow: -10px 0 30px rgba(0,0,0,0.5);
    overflow-y: auto;
    height: 100vh;
}

#sidebar::-webkit-scrollbar {
    width: 8px;
}

#sidebar::-webkit-scrollbar-track {
    background: rgba(255, 255, 255, 0.05);
    border-radius: 4px;
}

#sidebar::-webkit-scrollbar-thumb {
    background: var(--accent);
    border-radius: 4px;
}

#sidebar::-webkit-scrollbar-thumb:hover {
    background: var(--accent-hover);
}

.header { 
    display: flex; 
    align-items: center; 
    gap: 14px; 
    margin-bottom: 40px; 
}

.logo { 
    background: var(--accent); 
    padding: 10px; 
    border-radius: 12px; 
    display: flex;
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.4);
}

.logo-text {
    font-weight: 800;
    font-size: 20px;
    letter-spacing: -0.5px;
    background: linear-gradient(to right, #fff, #a1a1aa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* Upload Area */
.upload-area {
    background: var(--card-bg);
    border: 2px dashed var(--border);
    border-radius: 16px;
    padding: 40px 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    margin-bottom: 32px;
}

.upload-area:hover {
    border-color: var(--accent);
    background: #252529;
    transform: translateY(-2px);
}

/* HDR Drop Zone */
#hdr-drop-zone {
    background: var(--card-bg);
    border: 2px dashed var(--border);
    border-radius: 16px;
    padding: 40px 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    margin-bottom: 32px;
    position: relative;
    opacity: 0.8;
}

#hdr-drop-zone:hover {
    border-color: var(--accent);
    background: #252529;
    transform: translateY(-2px);
    opacity: 1;
}

#hdr-drop-zone.drag-over {
    border-color: #00ffcc;
    background: #1a2a27;
    opacity: 1;
}

.drop-zone-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.drop-zone-icon {
    font-size: 48px;
    margin-bottom: 16px;
    color: var(--accent);
}

.drop-zone-subtext {
    font-size: 14px;
    color: var(--text-dim);
    margin-top: 8px;
}

/* Control Groups */
.control-group { 
    margin-bottom: 28px; 
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border);
}

label { 
    display: block; 
    font-size: 11px; 
    color: var(--text-dim); 
    text-transform: uppercase; 
    letter-spacing: 1px;
    margin-bottom: 12px; 
    font-weight: 600;
}

/* Range Input Styling */
input[type="range"] {
    width: 100%;
    height: 6px;
    background: var(--border);
    border-radius: 10px;
    appearance: none;
    outline: none;
    margin: 10px 0;
}

input[type="range"]::-webkit-slider-thumb {
    appearance: none;
    width: 18px;
    height: 18px;
    background: var(--accent);
    border-radius: 50%;
    cursor: pointer;
    border: 3px solid var(--panel);
    transition: transform 0.1s ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

/* Button Grid */
.btn-row { 
    display: flex; 
    gap: 10px; 
    margin-top: 10px;
}

.icon-btn {
    flex: 1;
    background: var(--card-bg);
    border: 1px solid var(--border);
    color: var(--text-main);
    padding: 14px;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
}

.icon-btn:hover {
    background: var(--border);
    border-color: var(--accent);
    transform: translateY(-2px);
}

.icon-btn.active {
    background: var(--accent);
    border-color: var(--accent);
    color: white;
}

.control-row {
    display: flex;
    gap: 10px;
    margin-top: 10px;
}

/* Slider Group */
.slider-group {
    margin-top: 15px;
    padding: 10px 0;
}

.slider-group label {
    display: flex;
    justify-content: space-between;
    font-size: 12px;
    margin-bottom: 5px;
    color: var(--text-dim);
}

#light-intensity-value,
#flat-shading-value,
#metallic-value,
#roughness-value,
#fov-value,
#near-value,
#far-value,
#aa-value,
#resolution-value {
    color: var(--accent);
    font-weight: 600;
}

/* Loading & Overlay */
#loading {
    position: absolute;
    inset: 0;
    background: rgba(0,0,0,0.8);
    backdrop-filter: blur(8px);
    display: none;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 200;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border);
    border-top: 3px solid var(--accent);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 16px;
}

@keyframes spin { 
    0% { transform: rotate(0deg); } 
    100% { transform: rotate(360deg); } 
}

/* Responsive */
@media (max-width: 900px) {
    #app-container { flex-direction: column; }
    #sidebar { 
        width: 100%; 
        height: auto; 
        border-left: none; 
        border-top: 1px solid var(--border); 
        padding: 24px;
    }
    #viewport { height: 50vh; }
}