/**
 * Star Photo Share System
 * Star CSS - 星空背景、流星、银河、星云动画
 * Version 1.0
 * 2026-07-17
 *
 * 功能：动态星空背景（Canvas）、流星动画、银河渐层、星云特效
 */

/* ========================================
   星空背景容器
   ======================================== */
.star-background {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -2;
  background: linear-gradient(
    180deg,
    var(--galaxy-deep) 0%,
    var(--galaxy-blue) 40%,
    var(--galaxy-purple) 70%,
    var(--galaxy-deep) 100%
  );
  overflow: hidden;
}

/* ========================================
   Canvas 星空层
   ======================================== */
#starCanvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  pointer-events: none;
}

/* ========================================
   银河渐层叠加
   ======================================== */
.galaxy-layer {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(ellipse at 30% 20%, rgba(37, 99, 235, 0.08) 0%, transparent 50%),
    radial-gradient(ellipse at 70% 40%, rgba(124, 58, 237, 0.1) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 80%, rgba(6, 182, 212, 0.06) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 60%, rgba(37, 99, 235, 0.05) 0%, transparent 40%),
    radial-gradient(ellipse at 20% 70%, rgba(124, 58, 237, 0.07) 0%, transparent 40%);
  animation: nebulaMove 20s ease-in-out infinite;
}

/* ========================================
   星云（Nebula）
   ======================================== */
.nebula {
  position: fixed;
  border-radius: 50%;
  filter: blur(80px);
  z-index: -1;
  pointer-events: none;
  opacity: 0.15;
}

.nebula--1 {
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, var(--primary), transparent);
  top: 10%;
  left: -10%;
  animation: nebulaMove 25s ease-in-out infinite;
}

.nebula--2 {
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, var(--secondary), transparent);
  top: 40%;
  right: -10%;
  animation: nebulaMove 30s ease-in-out infinite reverse;
}

.nebula--3 {
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, var(--accent), transparent);
  bottom: 10%;
  left: 40%;
  animation: nebulaMove 22s ease-in-out infinite;
}

.nebula--4 {
  width: 350px;
  height: 350px;
  background: radial-gradient(circle, var(--star-yellow), transparent);
  top: 60%;
  left: 20%;
  opacity: 0.08;
  animation: nebulaMove 28s ease-in-out infinite reverse;
}

.nebula--5 {
  width: 450px;
  height: 450px;
  background: radial-gradient(circle, var(--primary-light), transparent);
  bottom: 20%;
  right: 20%;
  opacity: 0.1;
  animation: nebulaMove 24s ease-in-out infinite;
}

/* ========================================
   流星容器
   ======================================== */
.meteor-container {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  pointer-events: none;
  overflow: hidden;
}

/* ========================================
   流星元素
   ======================================== */
.meteor {
  position: absolute;
  width: 2px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 50%;
  animation: meteor 0.8s linear forwards;
  z-index: 0;
}

.meteor::before {
  content: '';
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 150px;
  height: 1px;
  background: linear-gradient(
    90deg,
    rgba(255, 255, 255, 0.8),
    rgba(255, 255, 255, 0.3),
    transparent
  );
}

/* 流星颜色变体 */
.meteor--blue {
  background: var(--primary-light);
}

.meteor--blue::before {
  background: linear-gradient(
    90deg,
    rgba(59, 130, 246, 0.8),
    rgba(59, 130, 246, 0.3),
    transparent
  );
}

.meteor--purple {
  background: var(--secondary-light);
}

.meteor--purple::before {
  background: linear-gradient(
    90deg,
    rgba(139, 92, 246, 0.8),
    rgba(139, 92, 246, 0.3),
    transparent
  );
}

.meteor--cyan {
  background: var(--accent-light);
}

.meteor--cyan::before {
  background: linear-gradient(
    90deg,
    rgba(34, 211, 238, 0.8),
    rgba(34, 211, 238, 0.3),
    transparent
  );
}

/* ========================================
   CSS 星星（备用，主要用 Canvas）
   ======================================== */
.css-star {
  position: absolute;
  width: 3px;
  height: 3px;
  background: var(--text-primary);
  border-radius: 50%;
  pointer-events: none;
}

.css-star--sm {
  width: 1px;
  height: 1px;
}

.css-star--lg {
  width: 4px;
  height: 4px;
  box-shadow: 0 0 6px rgba(255, 255, 255, 0.8);
}

.css-star--twinkle-1 { animation: twinkle 3s ease-in-out infinite; }
.css-star--twinkle-2 { animation: twinkle2 4s ease-in-out infinite; }
.css-star--twinkle-3 { animation: twinkle3 5s ease-in-out infinite; }