/* ===========================
   Global Styles
=========================== */

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

body {
    font-family: Arial, Helvetica, sans-serif;
    background: #f4f7fa;
    color: #333;
    line-height: 1.7;
}

/* ===========================
   Header
=========================== */

header {
    background: #0f172a;
    color: white;
    text-align: center;
    padding: 40px 20px;
}

header h1 {
    font-size: 2.6rem;
    margin-bottom: 10px;
}

.subtitle {
    color: #38bdf8;
    font-size: 1.15rem;
    margin-bottom: 25px;
}

/* ===========================
   Navigation
=========================== */

nav {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 15px;
}

nav a {
    color: white;
    text-decoration: none;
    font-weight: bold;
    padding: 10px 18px;
    border-radius: 6px;
    transition: 0.3s;
}

nav a:hover,
nav a[aria-current="page"] {
    background: #38bdf8;
    color: #0f172a;
}

/* ===========================
   Main Layout
=========================== */

main {
    max-width: 1100px;
    margin: auto;
    padding: 40px 20px;
}

/* ===========================
   Sections
=========================== */

section {
    background: white;
    margin-bottom: 30px;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,.08);
}

section h2 {
    color: #0f172a;
    margin-bottom: 20px;
    border-bottom: 2px solid #38bdf8;
    padding-bottom: 10px;
}

section p {
    margin-bottom: 18px;
}

/* ===========================
   Lists
=========================== */

ul {
    margin-left: 25px;
}

li {
    margin-bottom: 12px;
}

/* ===========================
   Buttons
=========================== */

.button,
button {
    display: inline-block;
    background: #38bdf8;
    color: #0f172a;
    text-decoration: none;
    font-weight: bold;
    padding: 12px 22px;
    border-radius: 8px;
    transition: .3s;
}

.button:hover,
button:hover {
    background: #0ea5e9;
    color: white;
}

/* ===========================
   Cards
=========================== */

.cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px,1fr));
    gap: 25px;
}

.card {
    background: white;
    padding: 25px;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,.08);
}

/* ===========================
   Images
=========================== */

img {
    max-width: 100%;
    border-radius: 10px;
    display: block;
    margin: 20px auto;
}

.image-caption {
    text-align: center;
    color: #666;
    font-style: italic;
    margin-top: -10px;
    margin-bottom: 15px;
}

/* ===========================
   Tables
=========================== */

table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
}

th {
    background: #0f172a;
    color: white;
}

th,
td {
    border: 1px solid #ddd;
    padding: 12px;
    text-align: left;
}

tr:nth-child(even) {
    background: #f7f7f7;
}

/* ===========================
   Footer
=========================== */

footer {
    background: #0f172a;
    color: white;
    text-align: center;
    padding: 25px;
    margin-top: 40px;
}

/* ===========================
   Responsive
=========================== */

@media (max-width: 768px) {

    header h1 {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    section {
        padding: 20px;
    }

    nav {
        flex-direction: column;
        align-items: center;
    }
}