:root { --bg-color: #ffffff; --text-color: #000000; --font-stack: "Helvetica Neue", Helvetica, Arial, sans-serif; --padding-x: 40px; --padding-y: 30px; --grid-gap: 20px; --align-guide: clamp(50%, calc(136.5vw - 886px), 75%); }
* { margin: 0; padding: 0; box-sizing: border-box; }
body { background-color: var(--bg-color); color: var(--text-color); font-family: var(--font-stack); -webkit-font-smoothing: antialiased; min-height: 100vh; padding-bottom: 0; overflow-x: hidden; }
a { text-decoration: none; color: inherit; }

header { padding: var(--padding-y) var(--padding-x); position: relative; display: flex; justify-content: space-between; align-items: flex-start; margin-bottom: 40px; height: 100px; }
.logo { display: block; cursor: pointer; position: relative; z-index: 10; }
.logo img { height: clamp(30px, 3.8vw, 55px); width: auto; display: block; }

.nav-group-right { position: absolute; left: var(--align-guide); top: var(--padding-y); z-index: 10; display: flex; gap: 40px; }
.nav-btn { font-size: clamp(1.9rem, 3.3vw, 4rem); font-weight: 400; line-height: 1; cursor: pointer; }
.nav-btn:hover { opacity: 0.6; }

main { padding: 0 var(--padding-x); margin-bottom: 20px; }
.portfolio-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: var(--grid-gap); align-items: start; }

.item { display: flex; justify-content: center; align-items: center; cursor: pointer; position: relative; z-index: 1; aspect-ratio: 1 / 1; overflow: hidden; background-color: #f9f9f9; opacity: 0; transform: translateY(100px); transition: opacity 0.2s ease, transform 0.2s ease; will-change: transform, opacity; }
.item.visible { opacity: 1; transform: translateY(0); transition: opacity 1.2s ease-out, transform 1.2s cubic-bezier(0.22, 1, 0.36, 1); }
.item img { width: 100%; height: 100%; object-fit: cover; display: block; }

footer { position: fixed; bottom: 0; left: 0; width: 100%; padding: 20px var(--padding-x); font-size: 0.75rem; font-weight: 700; text-transform: uppercase; z-index: 999; color: #333333; pointer-events: none; display: flex; justify-content: space-between; align-items: baseline; }
footer div { pointer-events: auto; }
.icp a { color: #333333; }

@media (max-width: 1200px) { .portfolio-grid { grid-template-columns: repeat(3, 1fr); } }
@media (max-width: 768px) {
    :root { --padding-x: 15px; --grid-gap: 10px; }
    .portfolio-grid { grid-template-columns: repeat(2, 1fr); }
    header { justify-content: space-between; height: auto; padding-top: 25px; }
   
    .nav-group-right { position: static; gap: 20px; }
    .nav-btn { font-size: 2rem; }
    footer { position: static; margin-top: 60px; display: flex; flex-direction: column; gap: 5px; padding-bottom: 40px; }
}

/* 视频封面（静音循环，无控件）填充方式同图片 */
.item video { width: 100%; height: 100%; object-fit: cover; display: block; }