html {
    box-sizing: border-box;
}

*,
*::before,
*::after {
    box-sizing: inherit;
}

body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    background: #eef3f8;
    color: #222;
    line-height: 1.6;
}

.back-button {
    position: relative;
    display: inline-block;
    margin: 1.5rem 0;
    padding: 0.75rem 1.5rem;
    color: #1f3c88;
    font-weight: bold;
    text-decoration: none;
    border-radius: 14px;
    background: rgba(255, 255, 255, 0.45);
    backdrop-filter: blur(10px);
    overflow: hidden;
    z-index: 0;
    transition: transform 0.25s ease, color 0.25s ease;
}

.back-button:hover {
    transform: translateY(-2px);
}


.back-button::before {
    content: "";
    position: absolute;
    inset: -2px;
    border-radius: 16px;
    background: conic-gradient(
    from 0deg,
    transparent 0deg,
    transparent 270deg,
    #1f3c88 300deg,
    #4a6cf7 330deg,
    transparent 360deg
);
    opacity: 0;
    animation: spinBorder 2s linear infinite;
    transition: opacity 0.25s ease;
    z-index: -1;
}


.back-button::after {
    content: "";
    position: absolute;
    inset: 2px;
    border-radius: 12px;
    background: rgba(255, 255, 255, 0.72);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    z-index: -1;
}


.back-button:hover::before {
    opacity: 1;
}

@keyframes spinBorder {
    0% {
        transform: rotate(0deg);
    }
    100% {
        transform: rotate(360deg);
    }
}

.wrapper {
    width: min(92%, 950px);
    margin: 2rem auto;
    background: #ffffff;
    border-radius: 16px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.12);
    overflow: hidden;
}

header {
    background: #1f3c88;
    color: white;
    padding: 2rem;
}

header h1 {
    margin-top: 0;
    margin-bottom: 0.75rem;
}

.intro {
    margin: 0;
}

main {
    padding: 2rem;
}

section {
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid #d9e2ec;
}

section:last-child {
    border-bottom: none;
}

h2 {
    color: #1f3c88;
    margin-top: 0;
}

code {
    background: #f4f4f4;
    padding: 0.15rem 0.35rem;
    border-radius: 4px;
    font-family: Consolas, Monaco, monospace;
    color: #b30000;
}

footer {
    background: #f7f9fc;
    text-align: center;
    padding: 1rem;
    border-top: 1px solid #d9e2ec;
}