:root {
    --bg-dark: #0f172a;
    --bg-panel: #1e293b;
    --bg-input: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --success: #10b981;
    --success-hover: #059669;
    --danger: #ef4444;
    --border: #334155;
}

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

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

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

/* Sidebar Styling */
.sidebar {
    width: 400px;
    background-color: var(--bg-panel);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    height: 100%;
    overflow-y: auto;
    box-shadow: 4px 0 15px rgba(0,0,0,0.2);
    z-index: 10;
}

.sidebar-header {
    padding: 24px;
    border-bottom: 1px solid var(--border);
}

.sidebar-header h1 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 8px;
    background: linear-gradient(135deg, #fff, #94a3b8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.sidebar-header p {
    font-size: 14px;
    color: var(--text-secondary);
}

form {
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.form-group.row {
    flex-direction: row;
    gap: 16px;
}

.form-group.row .col {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

label {
    font-size: 14px;
    font-weight: 500;
    color: var(--text-secondary);
}

input[type="text"], input[type="color"] {
    width: 100%;
    padding: 10px 12px;
    border-radius: 6px;
    border: 1px solid var(--border);
    background-color: var(--bg-input);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 14px;
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
}

input[type="text"]:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
}

input[type="color"] {
    padding: 0;
    height: 40px;
    cursor: pointer;
}

input[type="color"]::-webkit-color-swatch-wrapper {
    padding: 2px;
}

input[type="color"]::-webkit-color-swatch {
    border: none;
    border-radius: 4px;
}

.section-divider {
    height: 1px;
    background-color: var(--border);
    margin: 8px 0;
}

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

.section-title h3 {
    font-size: 16px;
    font-weight: 600;
}

/* Participants List */
#participants-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.participant-item {
    background-color: var(--bg-input);
    padding: 12px;
    border-radius: 8px;
    border: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.participant-header {
    display: flex;
    gap: 8px;
    align-items: center;
}

.participant-header .participant-name {
    flex: 1;
    background-color: var(--bg-panel);
}

.btn-remove-participant {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    border-radius: 4px;
    border: none;
    background-color: transparent;
    color: var(--text-secondary);
    font-size: 20px;
    cursor: pointer;
    transition: color 0.15s, background-color 0.15s;
}

.btn-remove-participant:hover {
    color: var(--danger);
    background-color: rgba(239, 68, 68, 0.1);
}

.participant-upload {
    display: flex;
    align-items: center;
    gap: 12px;
}

.file-label {
    display: inline-block;
    padding: 6px 12px;
    background-color: var(--border);
    border-radius: 4px;
    font-size: 12px;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s;
}

.file-label:hover {
    background-color: var(--text-secondary);
    color: var(--bg-dark);
}

.participant-image-input {
    display: none;
}

.file-name {
    font-size: 12px;
    color: var(--text-secondary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 130px;
}

/* Actions */
.actions {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-top: 16px;
}

.btn {
    padding: 12px;
    border-radius: 6px;
    border: none;
    font-family: inherit;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s, opacity 0.2s;
    color: white;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

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

.btn-primary:not(:disabled):hover {
    background-color: var(--accent-hover);
}

.btn-success {
    background-color: var(--success);
}

.btn-success:not(:disabled):hover {
    background-color: var(--success-hover);
}

.btn-small {
    padding: 4px 10px;
    border-radius: 4px;
    border: 1px solid var(--border);
    background-color: transparent;
    color: var(--text-primary);
    font-size: 12px;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s;
}

.btn-small:hover {
    background-color: var(--border);
}

/* Preview Area */
.preview-area {
    flex: 1;
    background-image: 
      linear-gradient(45deg, #1e293b 25%, transparent 25%), 
      linear-gradient(-45deg, #1e293b 25%, transparent 25%), 
      linear-gradient(45deg, transparent 75%, #1e293b 75%), 
      linear-gradient(-45deg, transparent 75%, #1e293b 75%);
    background-size: 20px 20px;
    background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 40px;
    overflow: hidden;
}

.canvas-wrapper {
    width: 100%;
    max-width: 1280px; /* Max nice preview size */
    aspect-ratio: 16 / 9;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    background-color: transparent;
    border: 2px solid var(--border);
    border-radius: 8px;
    overflow: hidden;
    position: relative;
}

canvas {
    width: 100%;
    height: 100%;
    object-fit: contain;
    display: block;
}