/* --- 基础设置 --- */
* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    background: radial-gradient(circle at center, #9b9898 0%, #0a0c10 60%, #1d2331 100%);
    font-family: 'Playfair Display', "PingFang SC", serif;
    color: #2c2c2c;
    line-height: 1.6;
}

/* 固定背景层 */
.fixed-background {
    position: fixed; top: 0; left: 0; width: 100%; height: 100vh;
    z-index: -1; pointer-events: none; overflow: hidden;
}

/* 桌面容器 */
.desk-container {
    width: 100%;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    padding: 60px 20px 100px 20px;
}

/* 2D 几何图形 */
.geo-shape {
    position: absolute;
    color: rgba(255, 255, 255, 0.8);
    pointer-events: none;
}

.circle-ring {
    width: 300px; height: 300px;
    border: 1px solid rgba(255, 255, 255, 0.5);
    border-radius: 50%;
    top: 10%; right: -50px;
}

.floating-plus {
    font-size: 100px; font-weight: 100;
    top: 40%; left: 10%;
}

.dash-line {
    width: 200vw; height: 1px;
    border-top: 1px dashed rgba(255, 255, 255, 0.1);
    top: 60%; left: -50%;
    transform: rotate(-15deg);
}

.triangle-outline {
    width: 0; height: 0;
    border-left: 50px solid transparent;
    border-right: 50px solid transparent;
    border-bottom: 80px solid rgba(255, 255, 255, 0.05);
    bottom: 10%; right: 20%;
}

/* --- 长信纸样式 --- */
.letter-paper {
    background-color: #fcfaf7;
    box-shadow: 0 0 50px rgba(0, 0, 0, 0.5), 0 0 20px rgba(255, 255, 255, 0.05);
    width: 100%;
    max-width: 700px;
    min-height: 120vh;
    position: relative;
    padding: 80px 60px;
    box-shadow: 0 10px 40px rgba(0,0,0,0.15);
    background-image: linear-gradient(#e6e6e6 1px, transparent 1px);
    background-size: 100% 40px; 
}

.grain-overlay {
    position: absolute; top: 0; left: 0; width: 100%; height: 100%;
    pointer-events: none; z-index: 0; 
    background: #fcfaf7;
    opacity: 0.92;
}

.grain-overlay::after {
    content: ""; position: absolute; top: 0; left: 0; width: 100%; height: 100%;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.8' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
    opacity: 0.08;
}

/* --- 内容排版 --- */
.hero-section, .section-block, .footer-section, .divider-line, .divider-dashed {
    position: relative; z-index: 10;
}

.hero-section { text-align: center; margin-bottom: 50px; }
.subtitle { font-size: 12px; letter-spacing: 3px; color: #999; margin-bottom: 10px; }
.hero-section h1 { font-size: 3rem; margin-bottom: 15px; }
.intro-text { max-width: 400px; margin: 0 auto; color: #666; font-style: italic; }

.divider-line { border: 0; border-top: 2px solid #333; margin: 40px 0; }
.divider-dashed { border: 0; border-top: 1px dashed #bbb; margin: 40px 0; }

h2 { font-size: 14px; text-transform: uppercase; letter-spacing: 2px; margin-bottom: 30px; color: #888; }

.grid-layout { display: grid; grid-template-columns: 100px 1fr; gap: 30px; }
.left-col h2 { margin: 0; color: #333; font-weight: 700; }
.tags-group { margin-top: 20px; }
.tags-group span {
    display: inline-block; background: #eee; padding: 4px 10px; 
    font-size: 12px; margin-right: 5px; border-radius: 4px; color: #555;
}

.timeline { border-left: 2px solid #eee; padding-left: 30px; }
.timeline-item { margin-bottom: 40px; position: relative; }
.timeline-item::before {
    content: ""; position: absolute; left: -36px; top: 6px;
    width: 10px; height: 10px; background: #333; border-radius: 50%;
}
.timeline-item .year { font-size: 12px; font-family: sans-serif; color: #999; margin-bottom: 5px; }
.timeline-item .role { font-size: 1.2rem; font-weight: 700; }
.timeline-item .company { font-style: italic; color: #666; margin-bottom: 10px; }
.timeline-item .desc { font-size: 0.95rem; color: #444; }

.gallery-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 20px; }
.gallery-item { text-align: center; }
.placeholder-img {
    width: 100%; height: 120px; border-radius: 4px; margin-bottom: 10px;
    border: 1px solid rgba(0,0,0,0.1); transition: transform 0.3s;
}
.gallery-item:hover .placeholder-img { transform: translateY(-5px); }
.caption { font-size: 12px; letter-spacing: 1px; }

.footer-section { text-align: center; margin-top: 60px; }
.signature { font-family: 'Dancing Script', cursive; font-size: 2.5rem; margin: 20px 0; }
.contact-info { font-size: 12px; line-height: 1.8; color: #888; font-family: sans-serif; }

.postage-stamp {
    position: absolute; top: 40px; right: 40px; width: 60px; height: 70px;
    background: #ccc; border: 4px solid #fff; box-shadow: 0 2px 5px rgba(0,0,0,0.2);
    z-index: 10;
}
.postmark {
    position: absolute; top: 50px; left: 40px; font-size: 10px; border: 1px solid #c00;
    color: #c00; padding: 2px 5px; transform: rotate(-10deg); opacity: 0.6; z-index: 10;
}

/* 几何导航轨 - PC端 */
.geo-nav-rail {
    position: fixed;
    left: 40px; top: 50%;
    transform: translateY(-50%);
    width: 40px; height: 80vh;
    display: flex; flex-direction: column; align-items: center;
    z-index: 100; cursor: pointer; user-select: none;
}

.rail-line {
    position: absolute; width: 1px; height: 100%;
    background: linear-gradient(to bottom, transparent, rgba(255, 255, 255, 0.5), transparent);
}

.rail-shapes {
    height: 100%;
    display: flex; flex-direction: column; justify-content: space-between;
    color: #ffffff; font-size: 18px; font-family: monospace; z-index: 2;
}

.r-shape { background: #000000; padding: 10px 0; transition: all 0.5s ease; }

.rail-hint {
    position: absolute; right: 40px; top: 50%;
    transform: rotate(-90deg) translateX(50%);
    transform-origin: right center;
    white-space: nowrap; color: rgba(255, 255, 255, 0.8);
    font-size: 13px; letter-spacing: 2px;
}

.jump-button {
    display: inline-block; margin-top: 50px; padding: 12px 35px;
    color: #333; text-decoration: none; font-size: 0.8rem; letter-spacing: 3px;
    border: 1px solid #333; position: relative; transition: all 0.4s ease;
    background: transparent; z-index: 10;
}

.jump-button:hover {
    color: #fff; background: #333;
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
}

.btn-line {
    position: absolute; bottom: -10px; left: 50%; transform: translateX(-50%);
    width: 0; height: 1px; background: #333; transition: width 0.4s ease;
}

.jump-button:hover .btn-line { width: 100%; }

/* ========================================= */
/*               移动端适配优化               */
/* ========================================= */
@media (max-width: 768px) {
    .desk-container { padding: 20px 15px 90px 15px; }
    
    .letter-paper { padding: 50px 25px 30px 25px; width: 100%; }

    .grid-layout { grid-template-columns: 1fr; gap: 15px; }
    
    .hero-section h1 { font-size: 2.2rem; }

    .postage-stamp { width: 45px; height: 55px; top: 20px; right: 20px; border-width: 3px; }
    .postmark { top: 25px; left: auto; right: 75px; font-size: 8px; opacity: 0.5; }

    .timeline { padding-left: 20px; }
    .timeline-item::before { left: -25px; }
    .timeline-item .role { font-size: 1.1rem; }

    .geo-nav-rail {
        left: 0; top: auto; bottom: 0; width: 100%; height: 60px;
        transform: none; flex-direction: row;
        background: rgba(3, 3, 3, 0.95);
        border-top: 1px solid rgba(255,255,255,0.15);
        padding: 0 30px; justify-content: center;
        box-shadow: 0 -5px 20px rgba(0,0,0,0.5);
    }

    .rail-line {
        width: 100%; height: 1px; top: 50%; left: 0;
        background: linear-gradient(to right, transparent, rgba(255, 255, 255, 0.4), transparent);
    }

    .rail-shapes {
        flex-direction: row; width: 100%; max-width: 300px;
        justify-content: space-between; align-items: center;
    }

    .r-shape { background: transparent; padding: 0 10px; text-shadow: 0 0 8px rgba(0,0,0,1); font-size: 16px; }

    .rail-hint { display: none; }

    .circle-ring { width: 150px; height: 150px; top: 5%; right: -30px; opacity: 0.3; }
    .floating-plus { font-size: 60px; left: 5%; top: 15%; opacity: 0.3; }
}