:root {
    --primary-100: #00B0FF;
    --primary-glow: rgba(0, 176, 255, 0.4);
    --highlight: #FF8C42;
    --highlight-glow: rgba(255, 140, 66, 0.4);
    --text-100: #FFFFFF;
    --text-200: #e0e0e0;
    --bg-100: #05090F;
    --bg-150: #0E1522;
    --bg-200: #161F2E;
    --bg-300: #242F42;
    
    --text80: rgba(255,255,255,0.8);
    --text60: rgba(255,255,255,0.6);
    --text40: rgba(255,255,255,0.3);

    --font-main: 'Noto Sans SC', sans-serif;
    --font-en: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    background-color: var(--bg-100);
    color: var(--text-100);
    font-family: var(--font-main);
    overflow-x: hidden;
    min-height: 100vh;
    background-image: linear-gradient(to right, var(--bg-100) 0%, rgba(5, 9, 15, 0.97) 40%, rgba(5, 9, 15, 0.85) 100%), 
                        url('/front-page-banner/T2-G3S.png');
    background-size: cover;
    background-position: center center;
    background-attachment: fixed;
    perspective: 1000px;

    /* 确保背景扩展到整个body */
    background-origin: border-box;
}

.container {
    width: 100%;
    max-width: 1600px;
    margin: 0 auto;
    padding: 0 5rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* --- Navbar (保持原样) --- */
nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 3rem 0;
}

.logo {
    display: flex;
    align-items: center;
    cursor: pointer;
    text-decoration: none;
    color: inherit;
}

.logo-box {
    width: 40px;
    height: 40px;
    /* background-color: var(--primary-100); */
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: 0.75rem;
    border-radius: 4px;
    /* box-shadow: 0 0 15px var(--primary-glow); */
}

.logo-box span {
    font-family: var(--font-en);
    font-weight: 900;
    color: var(--bg-100);
    font-size: 1.5rem;
}

.logo-text h1 {
    font-family: var(--font-main);
    font-size: 1.25rem;
    font-weight: 900;
    letter-spacing: -0.05em;
    line-height: 1;
}

.logo-text p {
    font-family: var(--font-en);
    font-size: 10px;
    letter-spacing: 0.1em;
    color: var(--text40);
    text-transform: uppercase;
    margin-top: 0.25rem;
}

.login-btn {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255,255,255,0.15);
    padding: 0.7rem 2.5rem;
    color: var(--text-100);
    font-family: var(--font-en);
    font-size: 11px;
    letter-spacing: 0.15em;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.3s ease;
    border-radius: 4px;
    backdrop-filter: blur(5px);
}

.login-btn:hover {
    border-color: var(--primary-100);
    color: var(--primary-100);
    background: rgba(0, 176, 255, 0.05);
    box-shadow: 0 0 20px rgba(0, 176, 255, 0.1);
}

/* --- Main Content --- */
main {
    flex-grow: 1;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 5rem 0;
    gap: 4rem;
}

.hero {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: flex-start;
}

.tag {
    background: rgba(255,255,255,0.05);
    border: 1px solid rgba(255,255,255,0.1);
    color: var(--primary-100);
    font-family: var(--font-en);
    font-size: 11px;
    padding: 0.25rem 0.75rem;
    letter-spacing: 0.1em;
    margin-bottom: 2rem;
    border-radius: 4px;
}

.hero h2 {
    font-size: 6rem;
    font-weight: 900;
    letter-spacing: -0.05em;
    line-height: 0.9;
    margin-bottom: 0.5rem;
}

.hero h2 span {
    color: var(--primary-100);
    text-shadow: 0 0 30px var(--primary-glow);
}

.hero .en-title {
    font-family: var(--font-en);
    font-size: 1.25rem;
    font-weight: 700;
    letter-spacing: 0.4em;
    color: var(--text40);
    margin-top: 1rem;
    margin-bottom: 2.5rem;
    text-transform: uppercase;
}

.hero p {
    font-size: 1.85rem;
    font-weight: 700;
    color: var(--text80);
    line-height: 1.3;
    max-width: 550px;
}

.hero p .highlight {
    color: var(--highlight);
}

/* --- Entrances (重点优化部分) --- */
.entrances {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 3rem;
    transform-style: preserve-3d;
}

.card {
    width: 100%;
    max-width: 560px;
    background: linear-gradient(135deg, #0e1525 0%, #05080f 100%);
    border: 2px solid rgba(255, 255, 255, 0.05);
    padding: 3rem;
    cursor: pointer;
    transition: all 0.6s cubic-bezier(0.23, 1, 0.32, 1);
    position: relative;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    text-decoration: none;
    color: inherit;
    border-radius: 8px;
    box-shadow: 20px 20px 60px rgba(0,0,0,0.5), 
                inset 1px 1px 0px rgba(255,255,255,0.05);
    transform-style: preserve-3d;
}

/* 背景图片层：Hover时浮现 */
.card-image-layer {
    position: absolute;
    top: 0;
    right: 0;
    width: 70%;
    height: 100%;
    z-index: 1;
    opacity: 0;
    transition: all 1.2s cubic-bezier(0.23, 1, 0.32, 1);
    pointer-events: none;
    background-size: cover;
    background-position: center;
    /* 图片左侧淡出效果 */
    mask-image: linear-gradient(to left, rgba(0,0,0,1) 0%, rgba(0,0,0,0) 100%);
    -webkit-mask-image: linear-gradient(to left, rgba(0,0,0,1) 0%, rgba(0,0,0,0) 100%);
    transform: translateX(40px) scale(1.1);
}

.card.library .card-image-layer {
    background-image: url('/front-page-banner/LIB-PIC-S.png');
}

.card.study .card-image-layer {
    background-image: url('/front-page-banner/STUDY-PIC-S.png');
}

.card:hover .card-image-layer {
    opacity: 0.3;
    transform: translateX(0) scale(1);
}

/* 移除卡片扫描线(card-scanner)相关代码 */

/* 卡片装饰边框 */
.card::before {
    content: '';
    position: absolute;
    top: -2px; left: -2px; right: -2px; bottom: -2px;
    background: linear-gradient(45deg, transparent 40%, rgba(255,255,255,0.1), transparent 60%);
    z-index: -1;
    border-radius: 10px;
    opacity: 0.5;
}

/* 内部发光追踪 */
.card-glow {
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    pointer-events: none;
    background: radial-gradient(circle at var(--mouse-x) var(--mouse-y), rgba(255,255,255,0.1) 0%, transparent 50%);
    border-radius: 8px;
    z-index: 5;
}

.card:hover {
    transform: translateZ(50px) rotateX(2deg) rotateY(-2deg);
    border-color: rgba(255,255,255,0.2);
}

.card.library:hover { 
    box-shadow: -20px 40px 80px rgba(0, 176, 255, 0.15); 
    border-color: var(--primary-100);
}
.card.study:hover { 
    box-shadow: -20px 40px 80px rgba(255, 140, 66, 0.15); 
    border-color: var(--highlight);
}

.card-inner {
    transform: translateZ(30px);
    position: relative;
    z-index: 10;
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 2rem;
}

.card-id {
    font-family: var(--font-en);
    font-size: 10px;
    color: var(--text40);
    letter-spacing: 0.3em;
    text-transform: uppercase;
    border: 1px solid rgba(255,255,255,0.1);
    padding: 2px 8px;
    border-radius: 2px;
    background: rgba(0,0,0,0.3);
}

.card-icon-box {
    width: 60px;
    height: 60px;
    background: rgba(255,255,255,0.02);
    border: 1px solid rgba(255,255,255,0.05);
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 4px;
    box-shadow: inset 0 0 10px rgba(0,0,0,0.5);
    transition: all 0.4s ease;
}

.card:hover .card-icon-box {
    transform: scale(1.1) translateZ(20px);
    background: rgba(255,255,255,0.05);
    border-color: currentColor;
}

.card-icon {
    width: 32px;
    height: 32px;
    transition: all 0.4s ease;
}

.card.library .card-icon { color: var(--primary-100); filter: drop-shadow(0 0 8px var(--primary-glow)); }
.card.study .card-icon { color: var(--highlight); filter: drop-shadow(0 0 8px var(--highlight-glow)); }

.card h3 {
    font-size: 3.5rem;
    font-weight: 900;
    margin-bottom: 1rem;
    transition: all 0.4s ease;
    letter-spacing: -0.02em;
    color: var(--text-200);
    text-shadow: 2px 2px 0px rgba(0,0,0,1);
}

.card:hover h3 {
    color: #fff;
    transform: translateZ(10px);
    text-shadow: 0 0 20px currentColor;
}

.card.library:hover h3 { color: var(--primary-100); }
.card.study:hover h3 { color: var(--highlight); }

.card p {
    color: var(--text60);
    font-size: 1.2rem;
    line-height: 1.6;
    max-width: 400px;
    transition: all 0.4s ease;
}

.card:hover p {
    color: var(--text-100);
    transform: translateZ(5px);
}

/* --- Footer (保持原样) --- */
footer {
    padding: 4rem 0;
    border-top: 1px solid rgba(255,255,255,0.05);
    display: flex;
    justify-content: flex-start;
    align-items: flex-end;
    gap: 4rem;
}

.footer-link {
    background: none;
    border: none;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    text-align: left;
    text-decoration: none;
    color: inherit;
}

.link-code {
    color: var(--primary-100);
    font-family: var(--font-en);
    font-size: 10px;
    letter-spacing: 0.1em;
    opacity: 0.5;
    margin-bottom: 0.25rem;
    text-transform: uppercase;
}

.link-text {
    color: var(--text40);
    font-size: 1.125rem;
    font-weight: 500;
    transition: all 0.3s ease;
}

.footer-link:hover .link-text {
    color: var(--text-100);
    transform: translateY(-2px);
}

.copyright {
    margin-left: auto;
    font-family: var(--font-en);
    font-size: 11px;
    color: var(--text40);
    letter-spacing: 0.2em;
    text-transform: lowercase;
    padding-bottom: 0.5rem;
}

@media (max-width: 1024px) {
    .container { padding: 0 2rem; }
    main { flex-direction: column; align-items: flex-start; }
    .entrances { align-items: flex-start; width: 100%; }
    .card { max-width: 100%; }
    .hero h2 { font-size: 4rem; }
    footer { flex-wrap: wrap; gap: 2rem; }
    .copyright { margin-left: 0; width: 100%; margin-top: 2rem; }
}