:root {
    --bg-color: #f6f8fa;
    --sidebar-bg: rgba(255, 255, 255, 0.9);
    --panel-bg: rgba(246, 248, 250, 0.8);
    --text-main: #24292f;
    --text-muted: #57606a;
    --border-color: #d0d7de;
    
    --accent-primary: #0969da;
    --accent-hover: #0353a4;
    --accent-success: #2da44e;
    --accent-success-hover: #2c974b;
    --accent-secondary: #57606a;
    --accent-secondary-hover: #424a53;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    height: 100vh;
    overflow: hidden;
    background-image: radial-gradient(circle at top right, #ffffff, #f6f8fa 40%);
}

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

/* Sidebar */
.sidebar {
    width: 420px;
    min-width: 420px;
    background-color: var(--sidebar-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    padding: 24px;
    overflow-y: auto; /* we want children to scroll specifically, but allow sidebar to scroll if screen is too small */
    box-shadow: 4px 0 25px rgba(0,0,0,0.5);
    z-index: 10;
}

.app-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 24px;
    text-align: center;
    color: #24292f;
    text-transform: uppercase;
    letter-spacing: 1px;
    background: -webkit-linear-gradient(45deg, #0969da, #8250df);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.control-group {
    background-color: var(--panel-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 16px;
    margin-bottom: 20px;
    transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s;
    backdrop-filter: blur(8px);
}

.control-group:hover {
    box-shadow: 0 4px 15px rgba(0,0,0,0.25);
    border-color: #484f58;
}

h3 {
    font-size: 0.95rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-main);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Upload Button */
.upload-btn {
    display: block;
    width: 100%;
    padding: 12px;
    background: linear-gradient(135deg, var(--accent-primary), #3182ce);
    color: #fff;
    text-align: center;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    transition: filter 0.2s, transform 0.1s;
    border: none;
    box-shadow: 0 2px 8px rgba(88, 166, 255, 0.3);
}

.upload-btn:hover {
    filter: brightness(1.1);
}
.upload-btn:active {
    transform: scale(0.98);
}

input[type="file"] {
    display: none;
}

.file-name {
    margin-top: 8px;
    font-size: 0.85rem;
    color: var(--text-muted);
    text-align: center;
    word-break: break-all;
}

.file-labels-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-top: 10px;
}

.file-label-item {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.file-label-item span {
    font-size: 0.8rem;
    color: var(--text-muted);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.file-label-item input {
    width: 100%;
    padding: 6px 10px;
    border-radius: 6px;
    background-color: rgba(255, 255, 255, 0.9);
    border: 1px solid var(--border-color);
    color: var(--text-main);
    font-size: 0.9rem;
    outline: none;
    transition: border-color 0.2s;
}

.file-label-item input:focus {
    border-color: var(--accent-primary);
}

/* Axis Limits */
.axis-inputs {
    margin-bottom: 12px;
}

.input-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 8px;
    font-size: 0.9rem;
}

.input-row input {
    width: 75px;
    background-color: rgba(255, 255, 255, 0.9);
    border: 1px solid var(--border-color);
    color: var(--text-main);
    padding: 6px 8px;
    border-radius: 6px;
    outline: none;
    font-family: inherit;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.input-row input:focus {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 2px rgba(88, 166, 255, 0.3);
}

.btn-group {
    display: flex;
    gap: 8px;
}

.btn {
    flex: 1;
    padding: 10px;
    border: none;
    border-radius: 6px;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
    color: #fff;
}

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

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

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

.btn-success { background-color: var(--accent-success); width: 100%; box-shadow: 0 2px 8px rgba(46, 160, 67, 0.3); }
.btn-success:hover { background-color: var(--accent-success-hover); }

/* Checkboxes */
.checkbox-label {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.85rem;
    color: var(--text-main);
    cursor: pointer;
    user-select: none;
}

.checkbox-label input[type="checkbox"] {
    accent-color: var(--accent-primary);
    width: 14px;
    height: 14px;
}

/* Trace Controls */
.trace-controls {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-height: 600px; 
    margin-bottom: 0;
    padding-bottom: 0;
}

.trace-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

.trace-header h3 { margin-bottom: 0; }

.btn-group-small {
    display: flex;
    gap: 6px;
}

.btn-small {
    background-color: var(--accent-secondary);
    color: #fff;
    border: none;
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.8rem;
    cursor: pointer;
    transition: background-color 0.2s, color 0.2s;
}

.btn-small:hover {
    background-color: var(--accent-main);
    color: #fff;
}

.trace-list {
    flex: 1;
    overflow-y: auto;
    padding-right: 4px;
    margin-bottom: 10px;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 6px;
}
::-webkit-scrollbar-track {
    background: transparent; 
}
::-webkit-scrollbar-thumb {
    background: #afb8c1; 
    border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
    background: #8c959f; 
}

.trace-group {
    margin-bottom: 12px;
}

.trace-group-title {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-main);
    background-color: rgba(240, 243, 246, 0.8);
    padding: 8px 10px;
    border-radius: 6px;
    margin-bottom: 6px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    transition: background-color 0.2s;
    border: 1px solid var(--border-color);
}

.trace-group-title:hover {
    background-color: rgba(224, 228, 232, 0.8);
}

.trace-item {
    display: flex;
    align-items: center;
    padding: 4px 0 4px 12px;
    border-radius: 4px;
    transition: background-color 0.1s;
}
.trace-item:hover {
    background-color: rgba(0,0,0,0.05);
}

.color-indicator {
    width: 14px;
    height: 14px;
    border-radius: 3px;
    margin-right: 10px;
    border: 1px solid rgba(0,0,0,0.15);
    box-shadow: 0 0 4px rgba(0,0,0,0.1);
}

.empty-state {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.9rem;
    padding: 20px 0;
    font-style: italic;
}

/* Main Content */
.main-content {
    flex: 1;
    position: relative;
    display: flex;
    padding: 24px;
}

.plot-container {
    flex: 1;
    width: 100%;
    height: 100%;
    border-radius: 12px;
    box-shadow: 0 4px 30px rgba(0,0,0,0.5);
    border: 1px solid var(--border-color);
    background-color: var(--bg-color);
}