.billy-app-container {
    --billy-orange: #F5A623; 
    --billy-dark: #333; 
    --billy-blue: #008080; 
    --bg-light: #f9f9f9; 
    --slate-200: #e2e8f0;
    --slate-500: #64748b;
    --slate-800: #1e293b;
    
    font-family: 'Segoe UI', 'Microsoft JhengHei', sans-serif;
    -webkit-font-smoothing: antialiased;
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
    color: var(--billy-dark);
}

.billy-app-container * {
    box-sizing: border-box;
}

.zh-text { color: #666; font-size: 0.9em; display: inline; font-weight: normal; }

.note-card { 
    background: var(--bg-light); 
    border-radius: 12px; 
    padding: 0; 
    margin: 20px 0; 
    box-shadow: 0 4px 15px rgba(0,0,0,0.05); 
    border-top: 4px solid var(--billy-blue); 
    overflow: hidden;
}

.card-header {
    padding: 20px 25px;
    border-bottom: 1px solid var(--slate-200);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background: #fff;
    gap: 15px;
}

.status-badge {
    padding: 6px 24px;
    border-radius: 9999px;
    font-size: 0.85rem;
    font-weight: 700;
    text-align: center;
    border: 1px solid transparent;
    transition: all 0.3s ease;
}
.status-running { background: #fee2e2; color: #b91c1c; border-color: #fecaca; animation: pulse 2s infinite; }
.status-paused { background: #e2e8f0; color: #475569; border-color: #cbd5e1; }

.hud-display {
    text-align: center;
    width: 100%;
    padding: 15px;
    background: var(--bg-light);
    border-radius: 8px;
    border: 1px solid var(--slate-200);
    position: relative;
    overflow: hidden;
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 10px;
}
@media (max-width: 600px) {
    .hud-display { grid-template-columns: 1fr; }
}
.hud-display::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; height: 4px;
    background: linear-gradient(90deg, var(--billy-blue), var(--billy-orange));
}
.hud-label {
    font-size: 0.85rem; font-weight: bold; color: var(--slate-500); text-transform: uppercase;
}
.hud-val {
    font-size: 1.2rem; font-weight: bold; color: var(--slate-800); line-height: 1.2; margin-top: 5px;
}

.diagram-container {
    position: relative;
    width: 100%;
    background: #0f172a;
    border-bottom: 1px solid var(--slate-200);
    padding: 0;
    line-height: 0;
    overflow: hidden;
    aspect-ratio: 16/10;
}
.diagram-container canvas {
    width: 100%; height: 100%; display: block;
}

.controls {
    padding: 25px; display: flex; flex-direction: column; gap: 20px; background: #fff;
}
.control-group {
    display: flex; flex-direction: column; gap: 10px;
}
.control-title {
    font-size: 0.875rem; font-weight: bold; color: var(--slate-500); text-transform: uppercase; letter-spacing: 0.05em;
}
.btn-group {
    display: flex; gap: 10px; width: 100%; flex-wrap: wrap;
}
.btn-toggle {
    flex: 1; min-width: 80px; padding: 10px; border-radius: 8px; font-weight: bold; font-size: 0.9rem; cursor: pointer; transition: all 0.2s; border: 2px solid var(--slate-200); background: white; color: var(--slate-600); display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 4px; text-align: center;
}
.btn-toggle:hover { background: var(--bg-light); }
.btn-toggle.active { background: var(--billy-blue); color: white; border-color: var(--billy-blue); }

.btn-action {
    background: white; border: 2px solid var(--billy-blue); color: var(--billy-blue); padding: 10px 20px; border-radius: 8px; font-weight: bold; cursor: pointer; transition: all 0.2s; display: flex; align-items: center; justify-content: center; gap: 8px; flex: 1;
}
.btn-action:hover { background: #f0f8f8; transform: translateY(-2px); }
.btn-action.primary { background: var(--billy-blue); color: white; }
.btn-action.primary:hover { background: #006666; }

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}
.no-select { user-select: none; -webkit-user-select: none; }