:root {
    --bg-color: #FAFAFA;
    --text-main: #111111;
    --text-sub: #666666;
    --brand-purple: #6D28D9;
    --brand-accent: #8B5CF6;
    --brand-gradient: linear-gradient(135deg, #6D28D9 0%, #A78BFA 100%);
    --border-light: rgba(0, 0, 0, 0.08);
    --shadow-float: 0 20px 40px -10px rgba(109, 40, 217, 0.15);
    --ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1);
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    overflow-x: hidden;
    line-height: 1.5;
    background-image: radial-gradient(#e5e7eb 1px, transparent 1px);
    background-size: 32px 32px;
    -webkit-font-smoothing: antialiased;
}

h1, h2, h3 { letter-spacing: -0.03em; font-weight: 800; }
a { text-decoration: none; color: inherit; }

.tech-tag {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--brand-accent);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    background: rgba(139, 92, 246, 0.08);
    padding: 4px 8px;
    border-radius: 4px;
    display: inline-block;
    margin-bottom: 0.8rem;
}

.fade-up {
    opacity: 0; transform: translateY(20px);
    transition: opacity 0.8s var(--ease-out), transform 0.8s var(--ease-out);
}
.fade-up.visible { opacity: 1; transform: translateY(0); }

/* 导航统一样式 */
nav {
    position: fixed; top: 0; left: 0; width: 100%; padding: 1rem 5%;
    display: flex; justify-content: center; align-items: center;
    background: rgba(250, 250, 250, 0.85);
    backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-light); z-index: 999;
}
.nav-container { max-width: 1200px; width: 100%; display: flex; justify-content: space-between; align-items: center; }
.brand { font-size: 1.2rem; font-weight: 900; display: flex; align-items: center; gap: 10px; }
.brand-icon {
    width: 32px; height: 32px;
    border-radius: 8px;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #f3f4f6;
}
.brand-icon img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}
.nav-menu { display: flex; align-items: center; gap: 2rem; list-style: none; }
.nav-menu li { position: relative; }
.nav-menu a { color: var(--text-main); font-size: 0.95rem; font-weight: 500; transition: color 0.3s; white-space: nowrap; position: relative; }
.nav-menu a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--brand-gradient);
    transition: width 0.3s;
}
@media (hover: hover) {
    .nav-menu a:hover { color: var(--brand-purple); }
    .nav-menu a:hover::after { width: 100%; }
}
.nav-menu a.active { color: var(--brand-purple); }
.nav-menu a.active::after { width: 100%; }
.mobile-menu-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: none; cursor: pointer; padding: 5px; }
.mobile-menu-toggle span { width: 24px; height: 2px; background: var(--text-main); transition: all 0.3s; border-radius: 2px; }
.mobile-menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(7px, 7px);
}
.mobile-menu-toggle.active span:nth-child(2) {
    opacity: 0;
}
.mobile-menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -7px);
}

.container { max-width: 1100px; margin: 0 auto; padding: 0 5%; }
.section { padding: 6rem 0; position: relative; }
.text-center { text-align: center; }

.hero { padding: 10rem 0 5rem; text-align: center; }
.hero h1 { font-size: clamp(2.5rem, 5vw, 3.5rem); margin-bottom: 1rem; }
.hero p { max-width: 600px; margin: 0 auto; color: var(--text-sub); font-size: 1.1rem; }

.card-grid {
    display: grid; grid-template-columns: repeat(3, 1fr); gap: 2rem; margin-top: 4rem;
}
.coop-card {
    background: white; border: 1px solid var(--border-light);
    border-radius: 16px; padding: 2rem;
    transition: all 0.3s var(--ease-out); position: relative;
}
@media (hover: hover) {
    .coop-card:hover {
        transform: translateY(-5px);
        border-color: var(--brand-purple);
        box-shadow: var(--shadow-float);
    }
}
.card-icon {
    width: 48px; height: 48px; background: #F3E8FF; border-radius: 10px;
    display: flex; align-items: center; justify-content: center;
    color: var(--brand-purple); margin-bottom: 1.5rem;
}
.coop-card h3 { margin-bottom: 0.8rem; font-size: 1.2rem; }
.coop-card p { font-size: 0.95rem; line-height: 1.6; }

.ability-item {
    display: flex; gap: 1rem; align-items: flex-start;
    padding: 1.5rem; border-bottom: 1px solid var(--border-light);
}
.ability-item:last-child { border-bottom: none; }
.ability-title { font-weight: 700; margin-bottom: 0.5rem; display: block; }

.process-wrapper {
    display: flex; justify-content: space-between; margin-top: 4rem; margin-left: auto; margin-right: auto; position: relative;
    max-width: 900px;
}
.process-wrapper::before {
    content: ''; position: absolute; top: 24px; left: 0; width: 100%; height: 2px;
    background: var(--border-light); z-index: 0;
}
.process-step {
    position: relative; z-index: 1; background: var(--bg-color); width: 22%;
    padding: 0 0.5rem; display: flex; flex-direction: column; align-items: center;
    text-align: center;
}
.step-num {
    font-family: var(--font-mono); font-weight: 700; color: var(--brand-purple);
    background: white; border: 1px solid var(--border-light);
    display: inline-block; padding: 4px 12px; border-radius: 20px;
    margin-bottom: 1rem; font-size: 0.9rem;
}
.process-step h3 { font-size: 1.1rem; margin-bottom: 0.5rem; }
.process-step p { font-size: 0.9rem; color: var(--text-sub); line-height: 1.5; }

.notice-box {
    background: white; border: 1px solid var(--border-light);
    border-left: 4px solid var(--brand-purple);
    border-radius: 8px; padding: 3rem; margin-top: 2rem;
    position: relative;
}
.notice-list { list-style: none; margin-top: 1.5rem; display: grid; grid-template-columns: repeat(3, 1fr); gap: 2rem; }
.notice-item { display: flex; align-items: flex-start; gap: 10px; }
.check-icon { color: var(--brand-accent); flex-shrink: 0; margin-top: 4px; }
.exclude-note {
    margin-top: 2rem; padding-top: 1.5rem; border-top: 1px dashed var(--border-light);
    font-size: 0.9rem; color: var(--text-sub); display: flex; gap: 10px;
}

.contact-section { text-align: center; background: white; border-top: 1px solid var(--border-light); }
.btn-primary {
    display: inline-block; background: var(--text-main); color: white;
    padding: 0.8rem 2.5rem; border-radius: 50px; font-weight: 600;
    transition: 0.3s; margin-top: 2rem;
}
@media (hover: hover) {
    .btn-primary:hover { transform: translateY(-2px); box-shadow: 0 10px 20px rgba(0,0,0,0.15); }
}

@media (max-width: 768px) {
    .nav-menu { display: none; }
    .mobile-menu-toggle { display: flex; }
    .nav-menu a { font-size: 1.1rem; padding: 1.2rem 0; }
    .card-grid { grid-template-columns: 1fr; }
    .process-wrapper { flex-direction: column; gap: 2rem; max-width: 480px; margin-left: auto; margin-right: auto; align-items: center; }
    .process-wrapper::before { 
        width: 2px; height: 100%; left: 50%; transform: translateX(-50%); top: 0; 
    }
    .hero h1 { font-size: 2.8rem; }
    .card { padding: 2rem; }
    .process-step { width: 100%; padding-left: 0; padding-right: 0; text-align: center; }
    .process-step .step-num { position: relative; left: auto; margin-left: auto; margin-right: auto; }
    .step-num { position: absolute; left: 0; top: 0; width: 30px; height: 30px; padding: 0; display: flex; align-items: center; justify-content: center; font-size: 0.8rem; }
    .notice-list { grid-template-columns: 1fr; gap: 1rem; }
}