/* =========================================================
   科技风全局样式（升级版 Tech 3.0）
========================================================= */

body {
    margin: 0;
    background: #030611;
    color: #bfe8ff;
    font-family: "Microsoft YaHei", Arial;
    overflow-x: hidden;
}

/* 页面切换淡入 */
body {
    animation: fadeIn 0.7s ease;
}
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* 顶部导航 */
nav {
    display: flex;
    justify-content: center;
    gap: 50px;
    padding: 18px;
    background: rgba(10,20,40,0.8);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid rgba(0,200,255,0.2);
}
nav a {
    color: #7cd8ff;
    text-decoration: none;
    font-size: 18px;
    transition: 0.3s;
    position: relative;
}
nav a:hover {
    color: #00eaff;
    text-shadow: 0 0 12px #00eaff;
}

/* 流光滑过效果 */
nav a::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: -4px;
    width: 0%;
    height: 2px;
    background: #00eaff;
    box-shadow: 0 0 12px #00eaff;
    transition: 0.4s;
}
nav a:hover::after {
    width: 100%;
}

/* 大容器 */
.container {
    width: 90%;
    max-width: 900px;
    margin: 40px auto;
}

/* 赛博朋克霓虹卡片 */
.card {
    background: rgba(10,30,60,0.5);
    padding: 25px;
    margin: 25px 0;
    border-radius: 12px;
    border: 1px solid rgba(0,200,255,0.4);
    box-shadow: 0 0 25px rgba(0,200,255,0.3);
    position: relative;
    overflow: hidden;
}

/* 动态流光边框 */
.card::before {
    content: "";
    position: absolute;
    top: 0; left: 0;
    width: 100%; height: 100%;
    border-radius: inherit;
    border: 2px solid transparent;
    animation: neonBorder 3s linear infinite;
}
@keyframes neonBorder {
    0% { box-shadow: 0 0 15px #00d0ff; }
    50% { box-shadow: 0 0 30px #00eaff; }
    100% { box-shadow: 0 0 15px #00d0ff; }
}

/* 流动光按钮 */
.btn {
    padding: 12px 28px;
    display: inline-block;
    color: #00eaff;
    border: 1px solid #00eaff;
    border-radius: 8px;
    text-decoration: none;
    position: relative;
    overflow: hidden;
    margin-right: 8px;
    transition: 0.3s;
}
.btn:hover {
    background: #00eaff;
    color: #00141f;
    box-shadow: 0 0 20px #00eaff;
}
.btn::before {
    content: "";
    position: absolute;
    top: 0; left: -100%;
    width: 100%; height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.7), transparent);
    animation: shine 1.8s infinite;
}
@keyframes shine {
    0% { left: -100%; }
    100% { left: 100%; }
}

/* 数字人展示（发光头像 + 呼吸动画） */
.ai-avatar {
    width: 160px;
    border-radius: 50%;
    margin: 20px auto;
    display: block;
    border: 3px solid #00eaff;
    box-shadow: 0 0 25px #00eaff;
    animation: breathing 3s infinite ease-in-out;
}
@keyframes breathing {
    0% { box-shadow: 0 0 15px #00eaff; }
    50% { box-shadow: 0 0 35px #00eaff; }
    100% { box-shadow: 0 0 15px #00eaff; }
}

/* 科技 HUD */
.hud {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 18px;
}
.hud-box {
    background: rgba(10,30,50,0.6);
    padding: 20px;
    border-radius: 8px;
    border: 1px solid #00d0ff;
    text-align: center;
    font-size: 20px;
    box-shadow: 0 0 20px rgba(0,200,255,0.3);
}