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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background: #f0f4f8;
    transition: background 0.3s, color 0.3s;
}

a {
    color: #1a73e8;
    text-decoration: none;
    transition: color 0.2s;
}

a:hover {
    text-decoration: underline;
    color: #0d47a1;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.sticky-nav {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    transition: box-shadow 0.3s, background 0.3s;
}

.nav-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 20px;
    max-width: 1200px;
    margin: 0 auto;
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: 700;
    color: #1a73e8;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
}

.nav-links {
    display: flex;
    gap: 24px;
    list-style: none;
}

.nav-links a {
    color: #333;
    font-weight: 500;
    position: relative;
    padding-bottom: 4px;
    transition: color 0.2s;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: #1a73e8;
    transition: width 0.3s ease;
}

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

.nav-links a:hover {
    color: #1a73e8;
    text-decoration: none;
}

.menu-toggle {
    display: none;
    cursor: pointer;
    font-size: 1.8rem;
    background: none;
    border: none;
    color: #333;
    transition: color 0.2s;
}

.menu-toggle:hover {
    color: #1a73e8;
}

.search-box {
    display: flex;
    gap: 8px;
}

.search-box input {
    padding: 8px 14px;
    border: 1px solid #d0d5dd;
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    transition: border-color 0.2s, box-shadow 0.2s;
}

.search-box input:focus {
    outline: none;
    border-color: #1a73e8;
    box-shadow: 0 0 0 3px rgba(26, 115, 232, 0.15);
}

.search-box button {
    padding: 8px 18px;
    background: linear-gradient(135deg, #1a73e8, #0d47a1);
    color: #fff;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 500;
    transition: transform 0.2s, box-shadow 0.2s;
}

.search-box button:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(26, 115, 232, 0.3);
}

.hero {
    background: linear-gradient(135deg, #1a73e8, #0d47a1, #1a73e8);
    background-size: 200% 200%;
    animation: gradientShift 8s ease infinite;
    color: #fff;
    padding: 80px 20px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
    animation: float 10s ease-in-out infinite;
}

@keyframes gradientShift {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

@keyframes float {
    0% { transform: translate(0, 0); }
    50% { transform: translate(30px, -30px); }
    100% { transform: translate(0, 0); }
}

.hero h1 {
    font-size: 2.6rem;
    margin-bottom: 16px;
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
    animation: fadeInUp 0.8s ease;
}

.hero p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto 24px;
    opacity: 0.9;
    animation: fadeInUp 0.8s ease 0.2s both;
}

.hero .btn {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    color: #1a73e8;
    padding: 14px 36px;
    border-radius: 12px;
    font-weight: 600;
    display: inline-block;
    transition: transform 0.3s, box-shadow 0.3s;
    animation: fadeInUp 0.8s ease 0.4s both;
}

.hero .btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
    text-decoration: none;
}

@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}

.section {
    padding: 60px 0;
}

.section-title {
    font-size: 2rem;
    margin-bottom: 40px;
    text-align: center;
    color: #1a73e8;
    position: relative;
    display: inline-block;
    left: 50%;
    transform: translateX(-50%);
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, #1a73e8, #0d47a1);
    border-radius: 2px;
}

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

.grid-3 {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 30px;
}

.card {
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-radius: 16px;
    padding: 28px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.06);
    transition: transform 0.3s ease, box-shadow 0.3s ease, background 0.3s;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.card:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 40px rgba(26, 115, 232, 0.12);
    background: rgba(255, 255, 255, 0.95);
}

.card h3 {
    margin-bottom: 12px;
    color: #1a73e8;
}

.card p {
    color: #555;
}

.breadcrumb {
    padding: 12px 0;
    font-size: 0.9rem;
    color: #666;
}

.breadcrumb a {
    color: #1a73e8;
}

.faq-item {
    border-bottom: 1px solid rgba(0, 0, 0, 0.08);
    padding: 18px 0;
    cursor: pointer;
    transition: background 0.2s;
    border-radius: 8px;
    padding-left: 12px;
    padding-right: 12px;
}

.faq-item:hover {
    background: rgba(26, 115, 232, 0.04);
}

.faq-question {
    font-weight: 600;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 1.05rem;
}

.faq-question span {
    font-size: 1.5rem;
    transition: transform 0.3s;
    color: #1a73e8;
}

.faq-item.active .faq-question span {
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.3s;
    padding-top: 0;
    color: #555;
    line-height: 1.7;
}

.faq-item.active .faq-answer {
    max-height: 600px;
    padding-top: 12px;
}

.howto-step {
    margin-bottom: 20px;
    padding-left: 24px;
    border-left: 3px solid #1a73e8;
    transition: border-color 0.3s;
}

.howto-step:hover {
    border-left-color: #0d47a1;
}

.howto-step h4 {
    margin-bottom: 6px;
    color: #1a73e8;
}

.article-list {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

.article-item {
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    padding: 22px;
    border-radius: 14px;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s, box-shadow 0.3s;
    border: 1px solid rgba(255, 255, 255, 0.4);
}

.article-item:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 28px rgba(26, 115, 232, 0.1);
}

.article-item h3 {
    font-size: 1.15rem;
    margin-bottom: 8px;
    color: #222;
}

.article-item .meta {
    font-size: 0.85rem;
    color: #888;
    margin-bottom: 8px;
}

.article-item p {
    font-size: 0.95rem;
    color: #555;
}

.article-item .read-more {
    color: #1a73e8;
    font-weight: 500;
    display: inline-block;
    transition: transform 0.2s;
}

.article-item .read-more:hover {
    transform: translateX(4px);
}

.footer {
    background: linear-gradient(135deg, #1a1a2e, #16213e);
    color: #ccc;
    padding: 48px 20px;
    font-size: 0.9rem;
}

.footer a {
    color: #aaa;
    transition: color 0.2s;
}

.footer a:hover {
    color: #fff;
    text-decoration: none;
}

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

.footer h4 {
    color: #fff;
    margin-bottom: 14px;
    font-size: 1.05rem;
}

.footer ul {
    list-style: none;
}

.footer ul li {
    margin-bottom: 8px;
}

.copyright {
    text-align: center;
    padding-top: 24px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    margin-top: 24px;
    color: #999;
}

.dark-mode {
    background: #121212;
    color: #e0e0e0;
}

.dark-mode .card {
    background: rgba(30, 30, 30, 0.85);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    color: #ddd;
    border-color: rgba(255, 255, 255, 0.1);
}

.dark-mode .card:hover {
    background: rgba(40, 40, 40, 0.95);
}

.dark-mode .sticky-nav {
    background: rgba(30, 30, 30, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
}

.dark-mode .nav-links a {
    color: #ccc;
}

.dark-mode .nav-links a:hover {
    color: #1a73e8;
}

.dark-mode .article-item {
    background: rgba(30, 30, 30, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-color: rgba(255, 255, 255, 0.1);
}

.dark-mode .article-item h3 {
    color: #eee;
}

.dark-mode .article-item p {
    color: #bbb;
}

.dark-mode .faq-item {
    border-color: rgba(255, 255, 255, 0.08);
}

.dark-mode .faq-item:hover {
    background: rgba(26, 115, 232, 0.08);
}

.dark-mode .faq-answer {
    color: #bbb;
}

.dark-mode .search-box input {
    background: rgba(255, 255, 255, 0.1);
    border-color: #555;
    color: #eee;
}

.dark-mode .search-box input:focus {
    border-color: #1a73e8;
}

.dark-mode .breadcrumb {
    color: #aaa;
}

.dark-mode .hero {
    background: linear-gradient(135deg, #0d47a1, #1a237e, #0d47a1);
    background-size: 200% 200%;
    animation: gradientShift 8s ease infinite;
}

.dark-mode .howto-step {
    border-left-color: #1a73e8;
}

.dark-mode .footer {
    background: linear-gradient(135deg, #0d0d1a, #1a1a2e);
}

.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: linear-gradient(135deg, #1a73e8, #0d47a1);
    color: #fff;
    width: 52px;
    height: 52px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.6rem;
    cursor: pointer;
    opacity: 0;
    transition: opacity 0.3s, transform 0.3s;
    border: none;
    box-shadow: 0 4px 16px rgba(26, 115, 232, 0.3);
}

.back-to-top:hover {
    transform: scale(1.1);
    box-shadow: 0 6px 24px rgba(26, 115, 232, 0.4);
}

.back-to-top.visible {
    opacity: 1;
}

.banner {
    position: relative;
    overflow: hidden;
    border-radius: 16px;
}

.banner-slide {
    display: none;
    animation: fadeIn 0.6s ease;
}

.banner-slide.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.banner-dots {
    text-align: center;
    margin-top: 12px;
}

.banner-dots span {
    display: inline-block;
    width: 12px;
    height: 12px;
    margin: 0 6px;
    background: #ccc;
    border-radius: 50%;
    cursor: pointer;
    transition: background 0.3s, transform 0.2s;
}

.banner-dots span.active {
    background: #1a73e8;
    transform: scale(1.3);
}

.banner-dots span:hover {
    background: #1a73e8;
}

.animate-number {
    font-size: 2rem;
    font-weight: 700;
    color: #1a73e8;
}

.scroll-animate {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.7s ease, transform 0.7s ease;
}

.scroll-animate.visible {
    opacity: 1;
    transform: translateY(0);
}

img[loading="lazy"] {
    background: #f0f0f0;
    border-radius: 8px;
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
        flex-direction: column;
        gap: 16px;
        background: rgba(255, 255, 255, 0.95);
        backdrop-filter: blur(12px);
        -webkit-backdrop-filter: blur(12px);
        position: absolute;
        top: 60px;
        left: 0;
        right: 0;
        padding: 24px;
        box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
        border-radius: 0 0 16px 16px;
    }

    .dark-mode .nav-links {
        background: rgba(30, 30, 30, 0.95);
    }

    .nav-links.open {
        display: flex;
    }

    .menu-toggle {
        display: block;
    }

    .grid-2,
    .grid-3,
    .article-list {
        grid-template-columns: 1fr;
    }

    .footer .grid-4 {
        grid-template-columns: 1fr 1fr;
    }

    .hero h1 {
        font-size: 1.8rem;
    }

    .hero p {
        font-size: 1rem;
    }

    .section-title {
        font-size: 1.6rem;
    }

    .card {
        padding: 20px;
    }

    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 44px;
        height: 44px;
        font-size: 1.4rem;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: 60px 16px;
    }

    .hero h1 {
        font-size: 1.5rem;
    }

    .nav-inner {
        padding: 10px 16px;
    }

    .section {
        padding: 40px 0;
    }

    .grid-2,
    .grid-3 {
        gap: 20px;
    }
}