:root {
    --primary-color: rgb(78, 84, 200);
    --secondary-color: rgb(143, 148, 251);
    --text-color: #333;
    --text-light: #666;
    --bg-light: #f8f9fa;
    --white: #ffffff;
    --glass-bg: rgba(255, 255, 255, 0.85);
    --glass-border: rgba(255, 255, 255, 0.3);
    --shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.15);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'KaiTi', 'STKaiti', serif; /* Use requested KaiTi font */
    color: var(--text-color);
    line-height: 1.6;
    background-color: var(--bg-light);
    overflow-x: hidden;
    font-size: 18px; /* Slightly larger base font for better readability with KaiTi */
}

a {
    text-decoration: none;
    color: var(--primary-color);
    transition: var(--transition);
}

ul {
    list-style: none;
}

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

.section-padding {
    padding: 80px 0;
}

.text-center {
    text-align: center;
}

/* Background Gradients & Effects */
.bg-gradient {
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
    color: var(--white);
}

.bg-glass {
    background-color: #f3f4fa;
    position: relative;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    margin-bottom: 15px;
    font-weight: 700;
    line-height: 1.3;
}

.section-title {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 10px;
}

.section-subtitle {
    font-size: 1.2rem;
    color: var(--text-light);
    margin-bottom: 40px;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 28px;
    border-radius: 30px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    outline: none;
    text-align: center;
}

.btn-large {
    padding: 15px 35px;
    font-size: 1.2rem;
}

.btn-full {
    width: 100%;
}

.btn-primary {
    background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
    color: var(--white);
    box-shadow: 0 4px 15px rgba(78, 84, 200, 0.4);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(78, 84, 200, 0.6);
    color: var(--white);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.2);
    color: var(--white);
    border: 1px solid var(--white);
    backdrop-filter: blur(5px);
}

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

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

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

/* Animations */
.pulse {
    animation: pulse-animation 2s infinite;
}

@keyframes pulse-animation {
    0% { box-shadow: 0 0 0 0 rgba(78, 84, 200, 0.7); }
    70% { box-shadow: 0 0 0 15px rgba(78, 84, 200, 0); }
    100% { box-shadow: 0 0 0 0 rgba(78, 84, 200, 0); }
}

.shine {
    position: relative;
    overflow: hidden;
}

.shine::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 50%;
    height: 100%;
    background: linear-gradient(to right, rgba(255,255,255,0) 0%, rgba(255,255,255,0.3) 50%, rgba(255,255,255,0) 100%);
    transform: skewX(-25deg);
    animation: shine-animation 3s infinite;
}

@keyframes shine-animation {
    0% { left: -100%; }
    20% { left: 200%; }
    100% { left: 200%; }
}

.fade-in-up {
    animation: fadeInUp 0.8s ease forwards;
}

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

.slide-in-right {
    animation: slideInRight 0.8s ease forwards;
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(50px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.tilt-effect {
    transition: transform 0.3s ease;
}

.tilt-effect:hover {
    transform: translateY(-10px) rotateX(5deg) rotateY(5deg);
}

/* Header & Nav */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    transition: var(--transition);
    background: transparent;
    padding: 20px 0;
}

.header.scrolled {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    padding: 10px 0;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 2rem;
    font-weight: bold;
    color: var(--white);
    transition: var(--transition);
}

.logo span {
    color: var(--white);
}

.header.scrolled .logo {
    color: var(--primary-color);
}

.nav-list {
    display: flex;
    gap: 30px;
    align-items: center;
}

.nav-list a {
    color: var(--white);
    font-weight: 600;
    font-size: 1.1rem;
}

.header.scrolled .nav-list a {
    color: var(--text-color);
}

.nav-list a:hover {
    color: var(--white);
}

.header.scrolled .nav-list a:hover {
    color: var(--primary-color);
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 5px;
}

.mobile-menu-toggle span {
    width: 30px;
    height: 3px;
    background-color: var(--white);
    transition: var(--transition);
}

.header.scrolled .mobile-menu-toggle span {
    background-color: var(--primary-color);
}

/* Hero Section */
.hero {
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
    color: var(--white);
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
    padding-top: 80px;
}

.hero::after {
    content: '';
    position: absolute;
    bottom: -50px;
    left: 0;
    width: 100%;
    height: 100px;
    background: var(--bg-light);
    transform: skewY(-2deg);
}

.hero-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 50px;
    position: relative;
    z-index: 10;
}

.hero-content {
    flex: 1;
}

.hero-title {
    font-size: 3.5rem;
    margin-bottom: 20px;
}

.highlight {
    color: var(--white);
}

.hero-subtitle {
    font-size: 1.3rem;
    margin-bottom: 40px;
    opacity: 0.9;
}

.hero-buttons {
    display: flex;
    gap: 20px;
    margin-bottom: 40px;
}

.hero-stats {
    display: flex;
    gap: 40px;
}

.stat-item {
    display: flex;
    flex-direction: column;
}

.stat-number {
    font-size: 2rem;
    font-weight: bold;
    color: var(--white);
}

.stat-label {
    font-size: 1rem;
    opacity: 0.8;
}

.hero-image {
    flex: 1;
    perspective: 1000px;
}

.mockup-card {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    border: 1px solid rgba(255,255,255,0.2);
    box-shadow: 0 20px 50px rgba(0,0,0,0.2);
    padding: 20px;
    transform: rotateY(-10deg) rotateX(5deg);
    transition: transform 0.5s;
}

.mockup-card:hover {
    transform: rotateY(0) rotateX(0);
}

.mockup-header {
    display: flex;
    gap: 8px;
    margin-bottom: 20px;
}

.dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
}

.dot.red { background: #ff5f56; }
.dot.yellow { background: #ffbd2e; }
.dot.green { background: #27c93f; }

.status-bar {
    background: rgba(255,255,255,0.2);
    padding: 15px;
    border-radius: 10px;
    display: flex;
    justify-content: space-between;
    margin-bottom: 30px;
}

.speed-graph {
    display: flex;
    align-items: flex-end;
    gap: 10px;
    height: 150px;
    padding: 10px;
}

.bar {
    flex: 1;
    background: linear-gradient(to top, rgba(255,255,255,0.5), rgba(255,255,255,1));
    border-radius: 5px 5px 0 0;
    animation: bar-grow 2s ease forwards;
    transform-origin: bottom;
}

.h-60 { height: 60%; }
.h-70 { height: 70%; }
.h-80 { height: 80%; }
.h-90 { height: 90%; }
.h-100 { height: 100%; }

@keyframes bar-grow {
    from { transform: scaleY(0); }
    to { transform: scaleY(1); }
}

/* Features Section */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.feature-card {
    background: var(--white);
    padding: 40px 30px;
    border-radius: 20px;
    box-shadow: var(--shadow);
    text-align: center;
    border: 1px solid rgba(0,0,0,0.05);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 20px;
    display: inline-block;
    padding: 15px;
    background: rgba(78, 84, 200, 0.1);
    border-radius: 50%;
    color: var(--primary-color);
}

.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: 15px;
}

/* Pricing Section */
.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    align-items: center;
}

.pricing-card {
    background: var(--white);
    border-radius: 20px;
    padding: 40px;
    box-shadow: var(--shadow);
    position: relative;
    border: 1px solid rgba(0,0,0,0.05);
}

.pricing-card.popular {
    transform: scale(1.05);
    border: 2px solid var(--primary-color);
    background: linear-gradient(to bottom, #ffffff, #f8f9fa);
}

.popular-badge {
    position: absolute;
    top: -15px;
    left: 50%;
    transform: translateX(-50%);
    background: linear-gradient(45deg, #ff416c, #ff4b2b);
    color: white;
    padding: 5px 20px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: bold;
    box-shadow: 0 5px 15px rgba(255, 65, 108, 0.4);
}

.pricing-header {
    text-align: center;
    margin-bottom: 30px;
    border-bottom: 1px solid #eee;
    padding-bottom: 20px;
}

.price {
    font-size: 3rem;
    font-weight: bold;
    color: var(--primary-color);
}

.price span {
    font-size: 1rem;
    color: var(--text-light);
}

.pricing-features {
    margin-bottom: 30px;
}

.pricing-features li {
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    gap: 10px;
}

/* Tutorial Section */
.tutorial-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 25px;
}

.tutorial-card {
    background: var(--white);
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.05);
    transition: var(--transition);
}

.tutorial-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0,0,0,0.1);
}

.tutorial-card h3 {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.3rem;
}

.tutorial-card .icon {
    font-size: 1.5rem;
}

.link-more {
    display: inline-block;
    margin-top: 15px;
    font-weight: bold;
}

/* FAQ Accordion */
.accordion {
    max-width: 800px;
    margin: 0 auto;
}

.accordion-item {
    margin-bottom: 15px;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0,0,0,0.05);
    background: var(--white);
}

.accordion-header {
    width: 100%;
    padding: 20px;
    text-align: left;
    background: var(--white);
    border: none;
    font-size: 1.2rem;
    font-weight: bold;
    color: var(--text-color);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition);
    font-family: 'KaiTi', 'STKaiti', serif;
}

.accordion-header:hover {
    color: var(--primary-color);
}

.accordion-header::after {
    content: '+';
    font-size: 1.5rem;
    color: var(--primary-color);
    transition: var(--transition);
}

.accordion-header.active::after {
    content: '-';
    transform: rotate(180deg);
}

.accordion-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
    background: #fafafa;
}

.accordion-content p {
    padding: 20px;
}

/* Articles Section */
.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
}

.article-card {
    background: var(--white);
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.05);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.article-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(78, 84, 200, 0.15);
}

.article-card h4 {
    color: var(--text-color);
    font-size: 1.2rem;
    margin-bottom: 15px;
}

.article-card:hover h4 {
    color: var(--primary-color);
}

.read-more {
    font-weight: bold;
    color: var(--primary-color);
    font-size: 0.9rem;
    align-self: flex-start;
}

/* Footer */
.footer {
    background: #1a1a2e;
    color: #fff;
    padding: 60px 0 20px;
}

.footer-content {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-brand .logo {
    margin-bottom: 15px;
}

.footer-brand p {
    opacity: 0.7;
    max-width: 300px;
}

.footer h3 {
    margin-bottom: 20px;
    font-size: 1.2rem;
}

.footer ul li {
    margin-bottom: 10px;
}

.footer ul a {
    color: rgba(255,255,255,0.7);
}

.footer ul a:hover {
    color: var(--white);
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid rgba(255,255,255,0.1);
    opacity: 0.6;
    font-size: 0.9rem;
}

/* Responsive */
@media (max-width: 992px) {
    .hero-container {
        flex-direction: column;
        text-align: center;
    }
    
    .hero-stats {
        justify-content: center;
    }
    
    .hero-buttons {
        justify-content: center;
    }

    .pricing-card.popular {
        transform: scale(1);
    }
}

@media (max-width: 768px) {
    .nav-list {
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: var(--glass-bg);
        backdrop-filter: blur(15px);
        flex-direction: column;
        align-items: center;
        padding: 20px 0;
        box-shadow: 0 10px 20px rgba(0,0,0,0.1);
        display: none;
    }

    .nav-list.active {
        display: flex;
    }
    
    .nav-list a {
        color: var(--text-color);
    }

    .nav-actions {
        display: none;
    }

    .mobile-menu-toggle {
        display: flex;
    }

    .header.scrolled .mobile-menu-toggle span, .mobile-menu-toggle span {
        background-color: var(--white);
    }
    .header.scrolled .mobile-menu-toggle span {
        background-color: var(--primary-color);
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
}

/* Specific Article Page Styles */
.article-header {
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
    color: var(--white);
    padding: 120px 0 60px;
    text-align: center;
}

.article-title {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.article-meta {
    font-size: 1rem;
    opacity: 0.8;
}

.article-content {
    background: var(--white);
    border-radius: 10px;
    padding: 40px;
    margin-top: -30px;
    box-shadow: var(--shadow);
    position: relative;
    z-index: 10;
    margin-bottom: 60px;
}

.article-content h2 {
    color: var(--primary-color);
    margin-top: 30px;
    margin-bottom: 15px;
    border-bottom: 2px solid #eee;
    padding-bottom: 10px;
}

.article-content h3 {
    margin-top: 25px;
    margin-bottom: 15px;
    color: #444;
}

.article-content p {
    margin-bottom: 20px;
    font-size: 1.1rem;
}

.article-content ul, .article-content ol {
    margin-bottom: 20px;
    padding-left: 20px;
}

.article-content li {
    margin-bottom: 10px;
}

.article-faq {
    margin-top: 50px;
    padding-top: 30px;
    border-top: 2px dashed #eee;
}

.article-nav {
    display: flex;
    justify-content: space-between;
    margin-top: 40px;
    border-top: 1px solid #eee;
    padding-top: 20px;
}