/* 爱思助手官方原创版 - CSS 样式 */
:root {
    --i4-blue: #0084FF;
    --i4-blue-deep: #0066CC;
    --i4-blue-light: #F0F7FF;
    --i4-text-main: #1D1D1F;
    --i4-text-sub: #86868B;
    --i4-bg-light: #F5F5F3;
    --i4-border: #E5E5E7;
    --i4-white: #FBFBF9;
    --i4-green: #28CD41;
    --i4-orange: #FF9F0A;
    --i4-purple: #AF52DE;
    --font-main: 'Inter', 'Noto Sans SC', sans-serif;
}

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

html { scroll-behavior: smooth; }

body {
    font-family: var(--font-main);
    color: var(--i4-text-main);
    background-color: var(--i4-white);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Navigation */
.i4-nav {
    height: 72px;
    background: rgba(249, 247, 242, 0.8);
    backdrop-filter: blur(20px);
    position: fixed;
    top: 0; width: 100%;
    z-index: 1000;
    border-bottom: 1px solid var(--i4-bg-light);
}

.nav-inner {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.i4-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 22px;
    font-weight: 800;
    color: var(--i4-blue);
    letter-spacing: -0.5px;
}

.logo-icon { width: 36px; height: 36px; }
.logo-icon.small { width: 28px; height: 28px; }

.nav-links { display: flex; gap: 40px; }
.nav-item {
    text-decoration: none;
    color: var(--i4-text-main);
    font-size: 15px;
    font-weight: 500;
    transition: 0.2s;
}
.nav-item:hover, .nav-item.active { color: var(--i4-blue); }

.btn-i4-nav {
    text-decoration: none;
    background: var(--i4-blue);
    color: white;
    padding: 8px 24px;
    border-radius: 50px;
    font-size: 14px;
    font-weight: 700;
    transition: 0.3s;
}
.btn-i4-nav:hover { background: var(--i4-blue-deep); transform: translateY(-1px); }

/* Hero Section */
.i4-hero {
    padding: 160px 0 100px;
    background: linear-gradient(180deg, #FDFDFB 0%, #FBFBF9 100%);
    overflow: hidden;
}

.hero-content {
    display: flex;
    align-items: center;
    gap: 80px;
}

.hero-text { flex: 1; }
.hero-h1 {
    font-size: 56px;
    font-weight: 900;
    line-height: 1.1;
    margin-bottom: 24px;
    letter-spacing: -1.5px;
}

.hero-h1 .highlight { color: var(--i4-blue); }

.hero-p {
    font-size: 20px;
    color: var(--i4-text-sub);
    margin-bottom: 48px;
    max-width: 520px;
}

.hero-btns {
    display: flex;
    gap: 20px;
    margin-bottom: 32px;
}

.btn-i4-main {
    text-decoration: none;
    background: var(--i4-blue);
    color: white;
    padding: 18px 36px;
    border-radius: 12px;
    font-size: 18px;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 12px;
    transition: 0.3s;
    box-shadow: 0 10px 20px rgba(0, 132, 255, 0.2);
}
.btn-i4-main:hover { transform: translateY(-3px); box-shadow: 0 15px 30px rgba(0, 132, 255, 0.3); }

.btn-i4-outline {
    text-decoration: none;
    border: 2px solid var(--i4-border);
    color: var(--i4-text-main);
    padding: 18px 36px;
    border-radius: 12px;
    font-size: 18px;
    font-weight: 700;
    transition: 0.3s;
}
.btn-i4-outline:hover { background: var(--i4-bg-light); border-color: var(--i4-text-main); }

.hero-meta {
    font-size: 14px;
    color: var(--i4-text-sub);
    display: flex;
    align-items: center;
    gap: 12px;
}
.hero-meta .divider { opacity: 0.3; }

/* Hero Window Mockup */
.hero-preview { flex: 1.2; position: relative; }
.i4-window {
    background: white;
    border-radius: 16px;
    box-shadow: 0 50px 100px rgba(0,0,0,0.1);
    border: 1px solid var(--i4-border);
    overflow: hidden;
    animation: windowFloat 6s infinite ease-in-out;
}

@keyframes windowFloat { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-20px); } }

.window-header {
    height: 40px;
    background: var(--i4-bg-light);
    display: flex;
    align-items: center;
    padding: 0 16px;
    position: relative;
}
.window-header .dots { display: flex; gap: 6px; }
.window-header .dots span { width: 10px; height: 10px; border-radius: 50%; }
.window-header .dots .r { background: #FF5F57; }
.window-header .dots .y { background: #FFBD2E; }
.window-header .dots .g { background: #28C840; }
.window-header .title {
    position: absolute; width: 100%; text-align: center; left: 0;
    font-size: 12px; color: var(--i4-text-sub); font-weight: 600;
}

.window-body { height: 380px; display: flex; }
.sidebar-mock { width: 140px; background: #F9FAFB; border-right: 1px solid #F0F0F2; padding: 24px 0; }
.side-item { 
    padding: 8px 24px; font-size: 12px; color: #4B5563; cursor: default;
    transition: 0.2s; font-weight: 500;
}
.side-item.active { background: #F3F4F6; color: var(--i4-blue); font-weight: 700; }

.content-mock { flex: 1; padding: 40px; display: flex; align-items: center; gap: 48px; background: white; }
.iphone-mock { 
    width: 110px; height: 220px; background: #F3F4F6; border-radius: 20px; 
    border: 1px solid #E5E7EB; position: relative;
}
.screen-content { 
    position: absolute; top: 8px; left: 8px; right: 8px; bottom: 8px;
    background: #fff; border-radius: 14px; border: 1px solid #F3F4F6;
}

.info-list-mock { flex: 1; }
.info-row { 
    display: flex; align-items: center; justify-content: space-between; 
    padding: 12px 0; border-bottom: 1px dotted #F0F0F2; font-size: 13px; 
}
.info-row:last-child { border-bottom: none; }
.info-row span { color: #9CA3AF; }
.info-row strong { color: #1F2937; font-weight: 600; }
.info-row strong.green { color: #10B981; }
.info-row strong.blue { color: var(--i4-blue); }

/* Features Grid */
.i4-features { padding: 120px 0; background: var(--i4-white); }
.sec-title-center { text-align: center; margin-bottom: 80px; }
.sec-title-center h2 { font-size: 40px; font-weight: 800; margin-bottom: 16px; }
.sec-title-center p { font-size: 18px; color: var(--i4-text-sub); }

.features-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.f-card {
    padding: 48px 32px;
    border-radius: 24px;
    background: var(--i4-bg-light);
    transition: 0.3s;
    text-align: center;
}
.f-card:hover { background: var(--i4-white); transform: translateY(-10px); box-shadow: 0 20px 40px rgba(0,0,0,0.05); }

.f-icon {
    width: 64px; height: 64px;
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 24px;
    color: white;
}
.f-icon svg { width: 32px; height: 32px; }
.f-icon.blue { background: var(--i4-blue); }
.f-icon.green { background: var(--i4-green); }
.f-icon.orange { background: var(--i4-orange); }
.f-icon.purple { background: var(--i4-purple); }

.f-card h3 { font-size: 20px; font-weight: 700; margin-bottom: 12px; }
.f-card p { font-size: 15px; color: var(--i4-text-sub); }

/* Showcase Section */
.i4-showcase { padding: 120px 0; background: #FAFAFB; }
.showcase-inner { display: flex; align-items: center; gap: 100px; }
.showcase-visual { flex: 1; display: flex; justify-content: center; }

.flashing-anim {
    width: 320px; height: 320px;
    background: white; border-radius: 50%;
    box-shadow: 0 20px 60px rgba(0,0,0,0.05);
    display: flex; flex-direction: column; align-items: center; justify-content: center;
    position: relative;
}
.progress-ring {
    width: 200px; height: 200px;
    border: 8px solid var(--i4-bg-light);
    border-top-color: var(--i4-blue);
    border-radius: 50%;
    animation: spin 2s linear infinite;
}
@keyframes spin { 100% { transform: rotate(360deg); } }
.status-txt { margin-top: 24px; font-size: 14px; font-weight: 600; color: var(--i4-blue); }

.showcase-text { flex: 1; }
.tag {
    display: inline-block; padding: 4px 12px; background: var(--i4-blue-light);
    color: var(--i4-blue); border-radius: 4px; font-size: 12px; font-weight: 700;
    margin-bottom: 16px;
}
.showcase-text h2 { font-size: 40px; font-weight: 800; margin-bottom: 24px; line-height: 1.2; }
.showcase-text p { font-size: 18px; color: var(--i4-text-sub); margin-bottom: 32px; }

.check-list { list-style: none; margin-bottom: 40px; }
.check-list li {
    margin-bottom: 16px; font-size: 16px; font-weight: 600;
    display: flex; align-items: center; gap: 12px;
}
.check-list li::before {
    content: '✓'; color: var(--i4-green); font-weight: 900;
}

.btn-i4-link {
    text-decoration: none; color: var(--i4-blue); font-weight: 700; font-size: 16px;
}
.btn-i4-link:hover { text-decoration: underline; }

/* Device Verification Section */
.i4-verification { padding: 120px 0; background: white; }
.ver-inner { display: flex; align-items: center; gap: 100px; }
.ver-text { flex: 1.2; }
.ver-text h2 { font-size: 40px; font-weight: 800; margin-bottom: 24px; }
.ver-text p { font-size: 18px; color: var(--i4-text-sub); margin-bottom: 40px; }
.tag.green { background: #E8F9EC; color: var(--i4-green); }

.ver-features { display: grid; grid-template-columns: 1fr 1fr; gap: 32px; }
.vf-item strong { display: block; font-size: 18px; color: var(--i4-text-main); margin-bottom: 8px; }
.vf-item p { font-size: 14px; color: var(--i4-text-sub); margin-bottom: 0; }

.ver-visual { flex: 0.8; display: flex; justify-content: center; }
.report-mock {
    width: 100%; max-width: 320px; background: #F8F8F9; border-radius: 24px;
    padding: 32px; border: 1px solid var(--i4-border); position: relative;
}
.report-header { font-size: 16px; font-weight: 700; margin-bottom: 24px; text-align: center; }
.rl-item { display: flex; justify-content: space-between; padding: 12px 0; border-bottom: 1px solid #EDEDF0; font-size: 14px; }
.rl-item:last-child { border-bottom: none; }
.status.ok { color: var(--i4-green); font-weight: 700; }
.report-score {
    position: absolute; top: -20px; right: -20px; width: 80px; height: 80px;
    background: var(--i4-green); color: white; border-radius: 50%;
    display: flex; flex-direction: column; align-items: center; justify-content: center;
    font-size: 28px; font-weight: 900; box-shadow: 0 10px 20px rgba(40, 205, 65, 0.3);
}
.report-score span { font-size: 12px; font-weight: 400; }

/* Multimedia Section */
.i4-multimedia { padding: 120px 0; background: #F5F5F7; }
.multi-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 32px; margin-top: 60px; }
.m-card {
    height: 400px; border-radius: 32px; overflow: hidden; position: relative;
    background-size: cover; background-position: center; transition: 0.4s;
}
.m-card.wallpaper { background-image: url('https://images.unsplash.com/photo-1618005182384-a83a8bd57fbe?auto=format&fit=crop&q=80&w=1000'); }
.m-card.ringtone { background-image: url('https://images.unsplash.com/photo-1511671782779-c97d3d27a1d4?auto=format&fit=crop&q=80&w=1000'); }
.m-card:hover { transform: scale(1.02); }

.m-overlay {
    position: absolute; bottom: 0; left: 0; width: 100%; padding: 48px;
    background: linear-gradient(to top, rgba(0,0,0,0.8), transparent);
    color: white;
}
.m-overlay h3 { font-size: 28px; font-weight: 800; margin-bottom: 12px; }
.m-overlay p { font-size: 16px; opacity: 0.8; margin-bottom: 24px; }
.m-overlay a {
    display: inline-block; padding: 12px 32px; background: white; color: var(--i4-text-main);
    text-decoration: none; border-radius: 50px; font-weight: 700; font-size: 14px;
    transition: 0.3s;
}
.m-overlay a:hover { background: var(--i4-blue); color: white; }

/* News & Tutorials Section */
.i4-news { padding: 120px 0; background: white; }
.news-layout { display: grid; grid-template-columns: 1.5fr 1fr; gap: 60px; }
.news-main h2 { font-size: 32px; font-weight: 800; margin-bottom: 40px; }
.news-list { display: flex; flex-direction: column; gap: 24px; }
.news-item { display: flex; gap: 24px; align-items: center; padding-bottom: 24px; border-bottom: 1px solid var(--i4-bg-light); }
.news-item .date { font-family: var(--font-main); font-size: 14px; color: var(--i4-text-sub); min-width: 60px; }
.news-item a { text-decoration: none; color: var(--i4-text-main); font-size: 16px; font-weight: 600; transition: 0.2s; }
.news-item a:hover { color: var(--i4-blue); }

.news-side { display: flex; flex-direction: column; gap: 32px; }
.side-box { padding: 40px; border-radius: 24px; background: #F8F8F9; border: 1px solid var(--i4-bg-light); }
.side-box.tutorial { background: var(--i4-blue-light); border-color: rgba(0, 132, 255, 0.1); }
.side-box h4 { font-size: 20px; font-weight: 700; margin-bottom: 12px; }
.side-box p { font-size: 14px; color: var(--i4-text-sub); margin-bottom: 24px; }
.side-box a { text-decoration: none; color: var(--i4-blue); font-weight: 700; font-size: 14px; }
.side-box a:hover { text-decoration: underline; }

/* Tools Section */
.i4-tools { padding: 120px 0; }
.tools-layout { display: flex; align-items: center; gap: 80px; }
.tools-text { flex: 1; }
.tools-text h2 { font-size: 40px; font-weight: 800; margin-bottom: 24px; }
.tools-text p { font-size: 18px; color: var(--i4-text-sub); }

.tools-grid { flex: 1.5; display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.t-item {
    background: var(--i4-bg-light); padding: 24px; border-radius: 16px;
    text-align: center; font-weight: 700; font-size: 15px; transition: 0.2s;
}
.t-item:hover { background: var(--i4-blue); color: white; transform: scale(1.05); }

/* Stats Section */
.i4-stats { padding: 80px 0; background: var(--i4-blue); color: white; }
.stats-inner { display: flex; justify-content: space-between; text-align: center; }
.stat-item .val { font-size: 48px; font-weight: 900; margin-bottom: 8px; }
.stat-item .lbl { font-size: 16px; opacity: 0.8; font-weight: 500; }

/* Footer */
.i4-footer { padding: 100px 0 40px; background: #F5F5F7; border-top: 1px solid var(--i4-border); }
.ft-top { display: flex; justify-content: space-between; gap: 100px; margin-bottom: 80px; }
.ft-brand { flex: 1.5; }
.ft-brand p { color: var(--i4-text-sub); font-size: 14px; margin-top: 24px; line-height: 1.8; }
.ft-links-grid { flex: 2; display: grid; grid-template-columns: repeat(3, 1fr); gap: 40px; }
.ft-col h4 { font-size: 15px; margin-bottom: 24px; color: var(--i4-text-main); }
.ft-col a { display: block; text-decoration: none; color: var(--i4-text-sub); font-size: 14px; margin-bottom: 12px; }
.ft-col a:hover { color: var(--i4-blue); }

.ft-bottom {
    padding-top: 40px; border-top: 1px solid var(--i4-border);
    display: flex; justify-content: space-between; font-size: 13px; color: var(--i4-text-sub);
}
.socials a { color: var(--i4-text-sub); text-decoration: none; margin-left: 24px; }
.socials a:hover { color: var(--i4-blue); }

/* Responsive */
@media (max-width: 1024px) {
    .hero-content, .showcase-inner, .tools-layout, .ft-top { flex-direction: column; text-align: center; }
    .hero-text { order: 2; }
    .hero-preview { order: 1; margin-bottom: 40px; }
    .hero-btns, .hero-meta { justify-content: center; }
    .features-grid, .tools-grid, .ft-links-grid { grid-template-columns: repeat(2, 1fr); }
    .stats-inner { flex-wrap: wrap; gap: 40px; justify-content: center; }
    .stat-item { flex-basis: 40%; }
}
@media (max-width: 640px) {
    .hero-h1 { font-size: 36px; }
    .features-grid, .tools-grid, .ft-links-grid { grid-template-columns: 1fr; }
    .nav-links { display: none; }
}