/* ===================================
   91助手电脑版 - 专业软件风格
   深蓝+橙色配色，科技感十足
   =================================== */

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

:root {
    --primary: #1e3a8a;
    --primary-light: #3b82f6;
    --accent: #f97316;
    --accent-dark: #ea580c;
    --dark: #0f172a;
    --gray-900: #1e293b;
    --gray-700: #334155;
    --gray-500: #64748b;
    --gray-300: #cbd5e1;
    --gray-100: #f1f5f9;
    --white: #ffffff;
    --gradient: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
}

html { scroll-behavior: smooth; font-size: 16px; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Noto Sans SC", sans-serif;
    line-height: 1.7;
    color: var(--dark);
    background: var(--white);
}

a { text-decoration: none; color: inherit; transition: 0.3s; }
img { max-width: 100%; height: auto; }

.container { max-width: 1140px; margin: 0 auto; padding: 0 20px; }

/* Header */
header {
    background: var(--white);
    box-shadow: 0 2px 10px rgba(0,0,0,0.08);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

nav { display: flex; justify-content: space-between; align-items: center; padding: 15px 0; }

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links { display: flex; gap: 30px; list-style: none; }

.nav-links a {
    color: var(--gray-700);
    font-weight: 500;
    padding: 8px 0;
    position: relative;
}

.nav-links a:hover, .nav-links a.active { color: var(--primary); }

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent);
    transition: 0.3s;
}

.nav-links a:hover::after { width: 100%; }

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
}

/* Hero */
.hero {
    background: var(--gradient);
    color: var(--white);
    padding: 160px 0 100px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 600px;
    height: 600px;
    background: rgba(255,255,255,0.05);
    border-radius: 50%;
}

.hero h1 {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    letter-spacing: -1px;
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: 2.5rem;
    opacity: 0.95;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.btn {
    display: inline-block;
    padding: 14px 35px;
    border-radius: 8px;
    font-weight: 600;
    font-size: 1rem;
    transition: 0.3s;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--accent);
    color: var(--white);
}

.btn-primary:hover { background: var(--accent-dark); transform: translateY(-2px); }

.btn-outline {
    background: transparent;
    color: var(--white);
    border: 2px solid var(--white);
    margin-left: 15px;
}

.btn-outline:hover { background: var(--white); color: var(--primary); }

/* Sections */
section { padding: 80px 0; }
.section-alt { background: var(--gray-100); }

.section-title {
    text-align: center;
    margin-bottom: 60px;
}

.section-title h2 {
    font-size: 2.5rem;
    color: var(--dark);
    margin-bottom: 15px;
}

.section-title p {
    color: var(--gray-500);
    font-size: 1.125rem;
}

/* Feature Cards */
.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.feature-card {
    background: var(--white);
    padding: 40px 30px;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.06);
    transition: 0.3s;
    border-top: 3px solid transparent;
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 35px rgba(0,0,0,0.12);
    border-top-color: var(--accent);
}

.feature-icon {
    width: 70px;
    height: 70px;
    background: var(--gradient);
    border-radius: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 25px;
    font-size: 2rem;
}

.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: 15px;
    color: var(--dark);
}

.feature-card p { color: var(--gray-500); }

/* Content Layout */
.content-split {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.content-text h2 {
    font-size: 2.25rem;
    margin-bottom: 20px;
    color: var(--dark);
}

.content-text p {
    color: var(--gray-500);
    margin-bottom: 15px;
    font-size: 1.0625rem;
}

.content-image {
    background: var(--gradient);
    border-radius: 15px;
    padding: 60px;
    min-height: 350px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--white);
    font-size: 1.25rem;
    box-shadow: 0 20px 60px rgba(30,58,138,0.3);
}

/* Stats */
.stats-bar {
    background: var(--dark);
    color: var(--white);
    padding: 60px 0;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
    text-align: center;
}

.stat-number {
    font-size: 3rem;
    font-weight: 700;
    color: var(--accent);
    margin-bottom: 10px;
}

.stat-label {
    color: var(--gray-300);
    font-size: 0.9375rem;
}

/* Download Section */
.download-section {
    background: var(--gradient);
    color: var(--white);
    padding: 100px 0;
    text-align: center;
}

.download-section h2 {
    font-size: 2.75rem;
    margin-bottom: 1.5rem;
}

.download-section p {
    font-size: 1.25rem;
    margin-bottom: 3rem;
    opacity: 0.95;
}

.download-buttons { display: flex; gap: 20px; justify-content: center; flex-wrap: wrap; }

.download-btn {
    background: var(--white);
    color: var(--primary);
    padding: 18px 40px;
    border-radius: 10px;
    font-weight: 600;
    font-size: 1.125rem;
    transition: 0.3s;
    display: inline-flex;
    align-items: center;
    gap: 10px;
}

.download-btn:hover { transform: scale(1.05); box-shadow: 0 10px 30px rgba(0,0,0,0.2); }

/* Footer */
footer {
    background: var(--dark);
    color: var(--gray-300);
    padding: 60px 0 30px;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h4 {
    color: var(--white);
    font-size: 1.125rem;
    margin-bottom: 20px;
}

.footer-section ul li { margin-bottom: 12px; }

.footer-section a:hover { color: var(--accent); }

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid var(--gray-900);
    color: var(--gray-500);
}

/* Breadcrumb */
.breadcrumb {
    background: var(--gray-100);
    padding: 20px 0;
    margin-top: 70px;
}

.breadcrumb nav { font-size: 0.875rem; color: var(--gray-500); }
.breadcrumb a { color: var(--primary); }

/* Page Header */
.page-header {
    background: var(--gradient);
    color: var(--white);
    padding: 180px 0 100px;
    text-align: center;
    margin-top: 70px;
}

.page-header h1 { font-size: 3rem; margin-bottom: 1rem; }
.page-header p { font-size: 1.25rem; opacity: 0.95; }

/* Responsive */
@media (max-width: 968px) {
    .features-grid { grid-template-columns: repeat(2, 1fr); }
    .content-split { grid-template-columns: 1fr; }
    .stats-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
    .hero h1 { font-size: 2.25rem; }
    section { padding: 60px 0; }
    
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--white);
        flex-direction: column;
        padding: 20px;
        gap: 15px;
        box-shadow: 0 10px 20px rgba(0,0,0,0.1);
    }
    
    .nav-links.active { display: flex; }
    .mobile-menu-btn { display: block; }
    .features-grid { grid-template-columns: 1fr; }
    .footer-content { grid-template-columns: 1fr; }
    .page-header h1 { font-size: 2rem; }
}