/**
 * Brand Chapter CSS — What is LunarStar
 * Phase 2 · Chapter 2
 *
 * 静谧 Nebula 空间：品牌文案逐句 Reveal + 四个漂浮 Orb
 * 不使用矩形 Card，纯圆形光球 + radial-gradient
 */

.brand-section {
    position: absolute;
    inset: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 4rem 2rem;
    /* Semi-transparent deep space overlay */
    background: transparent;
    overflow: hidden;
    pointer-events: none;
    z-index: 5;
}

/* Semi-transparent dark backdrop for content readability */
.brand-section::before {
    content: '';
    position: absolute;
    inset: 0;
    background: rgba(9, 13, 24, 0.55);
    z-index: -1;
    pointer-events: none;
}

/* 品牌文案 - 逐句 Reveal */
.brand-copy {
    text-align: center;
    margin-bottom: 4rem;
    pointer-events: auto;
}

.brand-line {
    font-family: 'Noto Serif SC', serif;
    font-size: clamp(1.2rem, 2.5vw, 1.8rem);
    font-weight: 300;
    color: rgba(200, 210, 240, 0.8);
    line-height: 1.8;
    margin: 0;
    opacity: 0;
    transform: translateY(20px);
}

/* Orb 布局 */
.brand-orbs {
    display: flex;
    gap: clamp(2rem, 6vw, 5rem);
    flex-wrap: wrap;
    justify-content: center;
    pointer-events: auto;
}

/* Orb 容器 */
.orb-container {
    position: relative;
    width: 140px;
    height: 140px;
    cursor: pointer;
    opacity: 0;
    transform: translateY(30px) scale(0.9);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

/* Orb 光晕 */
.orb-glow {
    position: absolute;
    inset: -20px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(100,140,220,0.15) 0%, transparent 70%);
    transition: background 0.6s ease, transform 0.6s ease;
}

.orb-container:hover .orb-glow {
    background: radial-gradient(circle, rgba(140,180,255,0.3) 0%, rgba(100,140,220,0.1) 50%, transparent 70%);
    transform: scale(1.2);
}

/* Orb 核心 */
.orb-core {
    position: absolute;
    inset: 0;
    border-radius: 50%;
    background: radial-gradient(circle at 35% 35%, rgba(160,190,240,0.4) 0%, rgba(80,110,180,0.2) 40%, rgba(30,50,90,0.3) 100%);
    border: 1px solid rgba(140,180,240,0.2);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    transition: border-color 0.6s, box-shadow 0.6s, transform 0.6s;
}

.orb-container:hover .orb-core {
    border-color: rgba(180,210,255,0.5);
    box-shadow: 0 0 40px rgba(100,160,240,0.2), 0 0 80px rgba(80,130,200,0.1);
    transform: scale(1.05);
}

/* Orb 标签 */
.orb-label {
    font-family: 'Inter', -apple-system, sans-serif;
    font-size: 0.85rem;
    font-weight: 500;
    letter-spacing: 0.25em;
    color: rgba(180,200,240,0.85);
    text-transform: uppercase;
    transition: opacity 0.3s;
}

.orb-container:hover .orb-label {
    opacity: 0;
}

/* Orb 展开内容 */
.orb-detail {
    position: absolute;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    opacity: 0;
    transform: scale(0.8);
    transition: opacity 0.3s, transform 0.3s;
    pointer-events: none;
}

.orb-container:hover .orb-detail {
    opacity: 1;
    transform: scale(1);
    pointer-events: auto;
}

.orb-detail span {
    font-family: 'Inter', -apple-system, sans-serif;
    font-size: 0.75rem;
    font-weight: 400;
    color: rgba(200,220,255,0.8);
    letter-spacing: 0.1em;
}