:root {
    --bg-dark: #0f0a1c;
    --bg-light: #1c1433;
    --matte-silver: #dcdce6;
    --silver-dark: #8c8c99;
    --accent-blue: #4a6bff;
    --accent-purple: #9d4edd;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

body, html {
    width: 100%;
    background-color: var(--bg-dark);
    font-family: 'Noto Serif SC', serif;
    color: var(--matte-silver);
    overflow-x: hidden;
    overscroll-behavior-y: none; /* 阻止 iOS 回弹，提升沉浸感 */
}

/* 进度条 */
.progress-bar-container {
    position: fixed;
    top: 0; left: 0; width: 100%; height: 3px;
    background: rgba(255,255,255,0.05);
    z-index: 999;
}
.progress-bar {
    height: 100%; width: 0%;
    background: linear-gradient(90deg, var(--accent-blue), var(--accent-purple), var(--matte-silver));
    box-shadow: 0 0 10px var(--accent-purple);
}

/* WebGL 背景层 */
#webgl-container {
    position: fixed;
    top: 0; left: 0; width: 100vw; height: 100dvh;
    z-index: 0;
    pointer-events: none;
}

/* 启动屏 (工业极简风) */
#entry-screen {
    position: fixed;
    top: 0; left: 0; width: 100vw; height: 100dvh;
    background: radial-gradient(circle at center, var(--bg-light) 0%, var(--bg-dark) 100%);
    z-index: 100;
    display: flex;
    justify-content: center; align-items: center;
    transition: opacity 1.2s ease, visibility 1.2s;
}
.entry-content {
    text-align: center;
    display: flex; flex-direction: column; align-items: center;
}
.silver-border-icon {
    margin-bottom: 30px;
    animation: rotateSlow 10s linear infinite;
}
@keyframes rotateSlow { 100% { transform: rotate(360deg); } }

.matte-title {
    font-size: 1.8rem; font-weight: 500;
    letter-spacing: 4px; margin-bottom: 15px;
    color: var(--matte-silver);
}
.matte-subtitle {
    font-size: 0.85rem; color: var(--silver-dark);
    letter-spacing: 2px; margin-bottom: 40px;
}

/* 拉丝金属质感按钮 */
.brushed-metal-btn {
    padding: 15px 35px;
    font-family: inherit; font-size: 1rem; letter-spacing: 2px;
    color: #111;
    background: linear-gradient(135deg, #f0f0f5 0%, #a0a0ab 50%, #dcdce6 100%);
    border: 1px solid rgba(255,255,255,0.8);
    border-radius: 50px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.5), inset 0 2px 5px rgba(255,255,255,0.8);
    transition: transform 0.2s, box-shadow 0.2s;
}
.brushed-metal-btn:active {
    transform: scale(0.95);
    box-shadow: 0 5px 15px rgba(0,0,0,0.5), inset 0 4px 10px rgba(0,0,0,0.3);
}

/* 滚动内容区 */
#scroll-container {
    position: relative;
    z-index: 10;
    opacity: 0;
    padding: 0 20px;
}
.spacer-vh { height: 85dvh; }
.spacer-vh-half { height: 40dvh; }

.card-section {
    min-height: auto;
    display: flex;
    justify-content: flex-start;
    margin-bottom: 60px;
}
.card-section.right-align { justify-content: flex-end; }

/* 哑光银玻璃态卡片 */
.glass-metal-card {
    width: 90%; max-width: 400px;
    background: rgba(28, 20, 51, 0.4);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(220, 220, 230, 0.15);
    border-top: 1px solid rgba(220, 220, 230, 0.3);
    border-radius: 16px;
    padding: 30px 25px;
    position: relative;
    box-shadow: 0 20px 40px rgba(0,0,0,0.4);
}

.card-header {
    display: flex; align-items: center; margin-bottom: 20px;
}
.chapter-num {
    font-size: 0.9rem; color: var(--accent-blue);
    font-weight: 700; letter-spacing: 1px;
}
.chapter-line {
    flex: 1; height: 1px; background: rgba(220, 220, 230, 0.2); margin-left: 15px;
}

.glass-metal-card p {
    font-size: 1rem; line-height: 2;
    margin-bottom: 1.2rem; font-weight: 300;
    color: rgba(220, 220, 230, 0.9); text-align: justify;
}
.glass-metal-card p:last-child { margin-bottom: 0; }

.full-focus {
    width: 100%; max-width: 100%;
    border-color: rgba(157, 78, 221, 0.4);
    text-align: center; padding: 40px 20px;
}
.highlight-silver {
    font-size: 1.1rem; font-weight: 500;
    color: #fff !important; text-shadow: 0 0 10px rgba(157, 78, 221, 0.5);
}

.end-card {
    width: 100%; max-width: 100%; text-align: center;
    padding: 60px 20px; background: rgba(15, 10, 28, 0.7);
    border: 1px solid rgba(220, 220, 230, 0.3); overflow: hidden;
}
.bg-mandala {
    position: absolute; top: 50%; left: 50%;
    transform: translate(-50%, -50%); width: 300px; height: 300px;
    pointer-events: none; opacity: 0.5; z-index: -1;
    animation: rotateSlow 20s linear infinite;
}
.silver-gradient-text {
    font-size: 1.6rem; margin-bottom: 20px; font-weight: 600;
    background: linear-gradient(135deg, #fff, var(--matte-silver), var(--accent-purple));
    -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.end-card h3 {
    font-size: 1.1rem; font-weight: 400; color: var(--matte-silver);
    margin-bottom: 30px; letter-spacing: 1px;
}