:root {
	/* 粒子專屬色：科技蔚藍 (Cyber Royal Blue) */
	--tech: #3b82f6;

	--bg-solid: #050b14;
	--bg-tint-1: rgba(37, 99, 235, 0.08);
	--bg-tint-2: rgba(96, 165, 250, 0.06);

	--line-base: rgba(59, 130, 246, 0.22);
	--line-glow: rgba(59, 130, 246, 0.85);
	--line-width: 1.5;
}

/* 主題容器鋪滿 */
#bg-particles.theme {
	position: fixed;
	inset: 0;
	pointer-events: none;
	overflow: hidden;
	z-index: -1;
	background:
		radial-gradient(900px 600px at 15% 12%, var(--bg-tint-1) 0%, transparent 100%),
		radial-gradient(900px 600px at 85% 88%, var(--bg-tint-2) 0%, transparent 100%),
		var(--bg-solid);
}

/* 暗角微調（避免邊緣過暗） */
#bg-particles.theme::after {
	content: "";
	position: absolute;
	inset: 0;
	background: radial-gradient(1100px 750px at 50% 50%, transparent 55%, rgba(0,0,0,.58) 100%);
	pointer-events: none;
}

/* 畫布鋪滿容器（實際像素由 JS 設定） */
#bg-particles-canvas {
	position: absolute;
	inset: 0;
	width: 100%;
	height: 100%;
	display: block;
	pointer-events: none;
	opacity: 0.88;
}

/* 🔮 粒子專屬：科技蔚藍光 Logo */
#theme-host[data-theme="bg-particles"] ~ main #indexTittle img {
    filter: drop-shadow(0 0 15px rgba(59, 130, 246, 0.85)) 
            drop-shadow(0 0 35px rgba(37, 99, 235, 0.55)) 
            drop-shadow(0 0 65px rgba(96, 165, 250, 0.25)) !important;
}

#theme-host[data-theme="bg-particles"] ~ main #indexTittle img:hover {
    filter: drop-shadow(0 0 20px rgba(59, 130, 246, 1)) 
            drop-shadow(0 0 50px rgba(37, 99, 235, 0.85)) 
            drop-shadow(0 0 85px rgba(96, 165, 250, 0.5)) !important;
}



/* RWD：小螢幕降低密度（JS 會讀取畫面大小自動調整，這裡只保留樣式） */
@media (prefers-reduced-motion: reduce) {
	#bg-particles-canvas { opacity: 0.45; }
}