/* ====== 高级加载界面 ====== */
#preloader {
    position: fixed;
    inset: 0;
    z-index: 9999;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #0c0e1a 0%, #1a1e3a 30%, #0f1923 60%, #0c0e1a 100%);
    overflow: hidden;
    transition: opacity 0.8s ease, visibility 0.8s ease;
}

#preloader.hidden { opacity: 0; visibility: hidden; pointer-events: none; }

/* 背景网格 */
.preloader-grid {
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(rgba(6,182,212,0.05) 1px, transparent 1px),
        linear-gradient(90deg, rgba(6,182,212,0.05) 1px, transparent 1px);
    background-size: 60px 60px;
    animation: gridMove 8s linear infinite;
    opacity: 0.6;
}

@keyframes gridMove {
    0% { transform: translate(0,0); }
    100% { transform: translate(60px,60px); }
}

/* 背景光晕 */
#preloader::before {
    content: '';
    position: absolute;
    width: 600px;
    height: 600px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(6,182,212,0.12), transparent 70%);
    animation: glowPulse 4s ease-in-out infinite;
    pointer-events: none;
}

#preloader::after {
    content: '';
    position: absolute;
    width: 500px;
    height: 500px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(139,92,246,0.08), transparent 70%);
    animation: glowPulse 4s ease-in-out infinite 2s;
    pointer-events: none;
}

@keyframes glowPulse {
    0%, 100% { transform: scale(1); opacity: 0.5; }
    50% { transform: scale(1.3); opacity: 1; }
}

/* 内部容器 */
.preloader-inner {
    position: relative;
    z-index: 1;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.75rem;
    padding: 2rem 1rem;
}

.preloader-logo { margin-bottom: 0.5rem; animation: logoFloat 3s ease-in-out infinite; }
.preloader-logo-img { height: 72px; filter: drop-shadow(0 0 20px rgba(6,182,212,0.4)); }

@keyframes logoFloat {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-8px); }
}

.preloader-title {
    font-size: 1.8rem;
    font-weight: 800;
    background: linear-gradient(135deg, #06b6d4, #3b82f6, #8b5cf6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: 2px;
    margin: 0;
    line-height: 1.3;
}

.preloader-subtitle {
    font-size: 0.85rem;
    color: rgba(148,163,184,0.7);
    letter-spacing: 4px;
    text-transform: uppercase;
    margin: 0;
}

.preloader-icon { margin: 0.5rem 0; font-size: 2rem; color: #06b6d4; animation: cubeSpin 2s ease-in-out infinite; }

@keyframes cubeSpin {
    0% { transform: rotateY(0deg) scale(1); opacity: 0.6; }
    50% { transform: rotateY(180deg) scale(1.2); opacity: 1; }
    100% { transform: rotateY(360deg) scale(1); opacity: 0.6; }
}

.preloader-bar-wrapper {
    width: 280px;
    height: 3px;
    background: rgba(255,255,255,0.08);
    border-radius: 4px;
    overflow: hidden;
    margin: 0.75rem 0 0.25rem;
    box-shadow: 0 0 10px rgba(6,182,212,0.15);
}

.preloader-bar {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, #06b6d4, #3b82f6, #8b5cf6, #06b6d4);
    background-size: 300% 100%;
    border-radius: 4px;
    animation: barGradient 2s linear infinite;
    transition: width 0.5s ease;
}

@keyframes barGradient {
    0% { background-position: 0% 50%; }
    100% { background-position: 300% 50%; }
}

.preloader-tip {
    font-size: 0.8rem;
    color: rgba(148,163,184,0.6);
    margin: 0.25rem 0 0;
    animation: tipFade 2s ease-in-out infinite;
    min-height: 1.2rem;
}

@keyframes tipFade {
    0%, 100% { opacity: 0.4; }
    50% { opacity: 1; }
}

.preloader-version {
    margin-top: 0.75rem;
    font-size: 0.7rem;
    color: rgba(148,163,184,0.25);
    letter-spacing: 1px;
    white-space: nowrap;
}

@media (max-width: 640px) {
    .preloader-title { font-size: 1.3rem; }
    .preloader-logo-img { height: 56px; }
    .preloader-bar-wrapper { width: 220px; }
    .preloader-icon { font-size: 1.6rem; }
    .preloader-inner { gap: 0.5rem; padding: 1.5rem 0.5rem; }
    #preloader::before { width: 300px; height: 300px; }
    #preloader::after { width: 250px; height: 250px; }
}