:root {
    --primary-color: #235d9b;
    --secondary-color: #41aee3;
    --background-color: #f5f9fc;
    --white-color: #ffffff;
    --text-color: #263238;
    --muted-color: #657786;
    --border-color: #d8e8f5;
    --shadow-color: rgba(35, 93, 155, 0.15);
}

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

html {
    scroll-behavior: smooth;
}

body {
    min-height: 100vh;
    font-family: Arial, Helvetica, sans-serif;
    color: var(--text-color);
    background: linear-gradient(
        180deg,
        var(--white-color) 0%,
        var(--background-color) 100%
    );
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

button {
    font: inherit;
}

.page-header {
    width: 100%;
    padding: 18px 24px;
    background-color: var(--white-color);
    border-bottom: 1px solid var(--border-color);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.04);
}

.header-content {
    width: min(1200px, 100%);
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: center;
}

.logo {
    width: 220px;
    max-width: 65%;
}

main {
    width: min(1200px, calc(100% - 32px));
    margin: 0 auto;
    padding: 55px 0 70px;
}

.introduction {
    max-width: 850px;
    margin: 0 auto;
    text-align: center;
}

.badge,
.pdf-badge {
    display: inline-block;
    margin-bottom: 16px;
    padding: 8px 16px;
    color: var(--primary-color);
    background-color: rgba(65, 174, 227, 0.12);
    border: 1px solid rgba(65, 174, 227, 0.25);
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

h1 {
    margin-bottom: 14px;
    color: var(--primary-color);
    font-size: clamp(2rem, 5vw, 3.4rem);
    line-height: 1.1;
}

.subtitle {
    color: var(--muted-color);
    font-size: clamp(1rem, 2vw, 1.2rem);
    line-height: 1.7;
}

.arrow-container {
    display: flex;
    justify-content: center;
    margin-top: 25px;
}

.arrow {
    width: 55px;
    color: var(--secondary-color);
    font-size: 45px;
    line-height: 1;
    animation: bounce 1.8s infinite ease-in-out;
}

.network-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 25px;
    margin-top: 45px;
}

.network-card {
    position: relative;
    min-height: 270px;
    padding: 32px 24px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    background-color: var(--white-color);
    border: 1px solid var(--border-color);
    border-radius: 18px;
    box-shadow: 0 8px 25px var(--shadow-color);
    overflow: hidden;
    cursor: pointer;
    transition:
        transform 0.25s ease,
        box-shadow 0.25s ease,
        border-color 0.25s ease;
}

.network-card::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 6px;
    background: linear-gradient(
        90deg,
        var(--primary-color),
        var(--secondary-color)
    );
}

.network-card:hover,
.network-card:focus-visible {
    transform: translateY(-8px);
    border-color: var(--secondary-color);
    box-shadow: 0 16px 35px rgba(35, 93, 155, 0.22);
}

.network-card:focus-visible {
    outline: 3px solid rgba(65, 174, 227, 0.35);
    outline-offset: 4px;
}

.card-icon {
    width: 92px;
    margin-bottom: 22px;
    transition: transform 0.25s ease;
}

.network-card:hover .card-icon {
    transform: scale(1.07);
}

.card-title {
    color: var(--primary-color);
    font-size: 1.05rem;
    font-weight: 700;
    line-height: 1.5;
}

.card-action {
    margin-top: 18px;
    color: var(--secondary-color);
    font-size: 0.9rem;
    font-weight: 700;
}

.information {
    max-width: 850px;
    margin: 45px auto 0;
    padding: 18px 22px;
    text-align: center;
    color: var(--muted-color);
    background-color: rgba(255, 255, 255, 0.8);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    line-height: 1.6;
}

.pdf-section {
    margin-top: 55px;
    padding: 22px;
    background: #eef5fa;
    border: 1px solid var(--border-color);
    border-radius: 18px;
    box-shadow: 0 10px 30px var(--shadow-color);
}

.pdf-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
    margin-bottom: 20px;
}

.pdf-header h2 {
    color: var(--primary-color);
    font-size: clamp(1.2rem, 3vw, 1.7rem);
    line-height: 1.3;
}

.pdf-badge {
    margin-bottom: 8px;
    font-size: 0.72rem;
}

.close-button {
    flex: 0 0 auto;
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 10px 15px;
    background: var(--white-color);
    color: var(--primary-color);
    font-weight: 700;
    cursor: pointer;
}

.close-button:hover {
    border-color: var(--secondary-color);
}

.pdf-loading,
.pdf-error {
    padding: 30px;
    text-align: center;
    background: var(--white-color);
    border-radius: 12px;
    color: var(--muted-color);
}

.pdf-error {
    color: #a33;
}

.pdf-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 18px;
}

.pdf-page {
    width: 100%;
    display: flex;
    justify-content: center;
    padding: 12px;
    background: #dfe9f1;
    border-radius: 8px;
    overflow-x: auto;
}

.pdf-page canvas {
    display: block;
    max-width: 100%;
    height: auto;
    background: white;
    box-shadow: 0 4px 16px rgba(0,0,0,.15);
}

footer {
    padding: 24px 16px;
    text-align: center;
    color: var(--muted-color);
    background-color: var(--white-color);
    border-top: 1px solid var(--border-color);
    font-size: 0.9rem;
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(8px); }
}

@media (max-width: 900px) {
    .network-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 620px) {
    .page-header { padding: 15px; }

    main {
        width: min(100% - 24px, 1200px);
        padding: 38px 0 50px;
    }

    .network-grid {
        grid-template-columns: 1fr;
        gap: 18px;
        margin-top: 35px;
    }

    .network-card {
        min-height: 230px;
        padding: 28px 20px;
    }

    .card-icon { width: 80px; }

    .information {
        margin-top: 30px;
        font-size: 0.92rem;
    }

    .pdf-section {
        padding: 14px;
    }

    .pdf-header {
        align-items: flex-start;
        flex-direction: column;
    }

    .close-button {
        width: 100%;
    }
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        scroll-behavior: auto !important;
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}