:root {
    --primary-gradient: linear-gradient(135deg, #7c9cc7 0%, #5a7ca8 100%);
    --secondary-gradient: linear-gradient(135deg, #8bb9d9 0%, #6ba3d6 100%);
    --tech-gradient: linear-gradient(135deg, #10b981 0%, #059669 100%);
    --dark-bg: #0f172a;
    --card-bg: rgba(255, 255, 255, 0.05);
    --text-primary: #f8fafc;
    --text-secondary: rgba(248, 250, 252, 0.85);
    --text-muted: rgba(248, 250, 252, 0.65);
    --border-color: rgba(255, 255, 255, 0.1);
    --accent-color: #7c9cc7;
    --accent-hover: #5a7ca8;
    --link-blue: #7c9cc7;
    --hover-blue: #5a7ca8;
}

* {
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--dark-bg);
    color: var(--text-primary);
    overflow-x: hidden;
    line-height: 1.6;
    margin: 0;
    padding: 0;
}

.hero-section {
    background: var(--primary-gradient);
    min-height: 80vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
}

.hero-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1000 1000"><defs><radialGradient id="a" cx="50%" cy="50%" r="50%"><stop offset="0%" stop-color="rgba(255,255,255,0.1)"/><stop offset="100%" stop-color="rgba(255,255,255,0)"/></radialGradient></defs><circle cx="200" cy="200" r="100" fill="url(%23a)"/><circle cx="800" cy="300" r="150" fill="url(%23a)"/><circle cx="600" cy="700" r="120" fill="url(%23a)"/></svg>');
    opacity: 0.3;
}

.hero-content {
    position: relative;
    z-index: 2;
}

.hero-title {
    font-size: 4rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
    animation: fadeInUp 1s ease-out;
}

.hero-subtitle {
    font-size: 1.3rem;
    margin-bottom: 2rem;
    opacity: 0.9;
    animation: fadeInUp 1s ease-out 0.3s both;
}

.cta-button {
    background: var(--secondary-gradient);
    border: none;
    padding: 15px 40px;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 50px;
    text-transform: uppercase;
    letter-spacing: 1px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 8px 25px rgba(0,0,0,0.3);
    animation: fadeInUp 1s ease-out 0.6s both;
    color: white;
    text-decoration: none;
    display: inline-block;
    cursor: pointer;
}

.cta-button:hover {
    transform: translateY(-3px);
    box-shadow: 0 12px 35px rgba(0,0,0,0.4);
    color: white;
}

.topics-section {
    padding: 80px 0;
    background: var(--dark-bg);
}

.topic-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 40px 30px;
    text-align: center;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    backdrop-filter: blur(10px);
    height: 100%;
    position: relative;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.topic-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--primary-gradient);
    transform: scaleX(0);
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.topic-card:hover::before {
    transform: scaleX(1);
}

.topic-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0,0,0,0.3);
    background: rgba(255,255,255,0.08);
    border-color: rgba(255,255,255,0.15);
}

.topic-icon {
    font-size: 3rem;
    margin-bottom: 20px;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.topic-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.topic-description {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 20px;
    flex-grow: 1;
    font-size: 1rem;
}

.topic-link {
    color: var(--accent-color);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    margin-top: auto;
    border-bottom: 1px solid transparent;
}

.topic-link:hover {
    color: var(--accent-hover);
    border-bottom-color: var(--accent-hover);
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 60px;
    position: relative;
    color: var(--text-primary);
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: var(--primary-gradient);
    border-radius: 2px;
}

.featured-article {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 40px;
    margin-top: 60px;
    backdrop-filter: blur(10px);
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.featured-article:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0,0,0,0.3);
}

.article-title {
    font-size: 1.8rem;
    font-weight: 600;
    color: var(--accent-color);
    margin-bottom: 10px;
    line-height: 1.4;
}

.article-date {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 25px;
    font-style: italic;
}

.article-content {
    color: var(--text-secondary);
    line-height: 1.8;
    font-size: 1rem;
}

.article-content p {
    margin-bottom: 20px;
}

.article-list {
    padding-left: 20px;
    margin: 25px 0;
}

.article-list li {
    margin-bottom: 8px;
    color: var(--text-secondary);
    position: relative;
    line-height: 1.8;
}

.article-list li::before {
    content: '▸';
    color: var(--accent-color);
    font-weight: bold;
    position: absolute;
    left: -20px;
}

.article-image {
    max-width: 100%;
    height: auto;
    border-radius: 12px;
    margin: 30px 0;
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
}

.article-section-title {
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: 40px 0 20px 0;
    padding-bottom: 10px;
    border-bottom: 2px solid rgba(124, 156, 199, 0.5);
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.article-link {
    color: var(--accent-color);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border-bottom: 1px solid transparent;
}

.article-link:hover {
    color: var(--accent-hover);
    border-bottom-color: var(--accent-hover);
}

.divider {
    border: none;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--border-color), transparent);
    margin: 50px 0;
}

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

.floating-elements {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
}

.floating-element {
    position: absolute;
    opacity: 0.1;
    animation: float 6s ease-in-out infinite;
}

.floating-element:nth-child(1) { top: 20%; left: 10%; animation-delay: 0s; }
.floating-element:nth-child(2) { top: 60%; right: 10%; animation-delay: 2s; }
.floating-element:nth-child(3) { bottom: 20%; left: 20%; animation-delay: 4s; }

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

a:focus,
button:focus {
    outline: 2px solid var(--hover-blue);
    outline-offset: 2px;
    border-radius: 4px;
}

::selection {
    background: rgba(124, 156, 199, 0.3);
    color: var(--text-primary);
}

::-moz-selection {
    background: rgba(124, 156, 199, 0.3);
    color: var(--text-primary);
}

::-webkit-scrollbar {
    width: 12px;
}

::-webkit-scrollbar-track {
    background: var(--dark-bg);
}

::-webkit-scrollbar-thumb {
    background: var(--primary-gradient);
    border-radius: 6px;
    border: 2px solid var(--dark-bg);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--secondary-gradient);
}

@media (max-width: 992px) {
    .hero-title {
        font-size: 3rem;
    }

    .section-title {
        font-size: 2rem;
    }

    .topics-section {
        padding: 60px 0;
    }

    .topic-card {
        margin-bottom: 30px;
    }

    .featured-article {
        padding: 30px;
    }
}

@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        font-size: 1.1rem;
    }

    .section-title {
        font-size: 1.8rem;
        margin-bottom: 40px;
    }

    .topic-card {
        padding: 30px 20px;
    }

    .featured-article {
        padding: 25px;
    }

    .article-title {
        font-size: 1.5rem;
    }
}

@media (max-width: 576px) {
    .topics-section {
        padding: 40px 0;
    }

    .featured-article {
        padding: 20px;
    }

    .article-image {
        margin: 20px 0;
    }
}

@media (prefers-reduced-motion: reduce) {
    * {
        transition: none !important;
        animation: none !important;
        transform: none !important;
    }
}