/* Basic reset for consistent sizing */
* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    line-height: 1.6;
    color: #1f2933;
    background-color: #f4f7f9;
}

/* Header uses Flexbox on desktop */
header {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 50px 5%;
    text-align: center;
    color: white;
    background: linear-gradient(135deg, #174a6e, #2f7d89);
}

header h1 {
    margin: 0;
    font-size: 50px;
}

header p {
    max-width: 750px;
}

/* Flexible navigation */
nav {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 12px;
    margin-top: 15px;
}

nav a {
    padding: 10px 18px;
    color: white;
    text-decoration: none;
    border: 1px solid white;
    border-radius: 25px;
}

nav a:hover {
    color: #174a6e;
    background-color: white;
}

main {
    width: 92%;
    max-width: 1100px;
    margin: auto;
    padding: 35px 0;
}

.information {
    margin-bottom: 30px;
    padding: 25px;
    background-color: white;
    border-left: 6px solid #2f7d89;
    border-radius: 10px;
}

.information h2 {
    margin-top: 0;
}

/* Desktop Grid: three columns */
.card-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.card {
    overflow: hidden;
    background-color: white;
    border-radius: 15px;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.12);
}

/* Responsive images */
.card img {
    display: block;
    width: 100%;
    height: 220px;
    object-fit: cover;
}

.card-text {
    padding: 20px;
}

.card-text h2 {
    margin-top: 0;
}

/* Flexbox section */
.techniques {
    display: flex;
    justify-content: space-between;
    gap: 30px;
    margin-top: 30px;
    padding: 25px;
    background-color: #dfeff1;
    border-radius: 15px;
}

.techniques div,
.techniques ul {
    flex: 1;
}

.techniques h2 {
    margin-top: 0;
}

footer {
    padding: 20px;
    text-align: center;
    color: white;
    background-color: #17324d;
}

/* Tablet layout: two columns */
@media screen and (max-width: 850px) {
    header h1 {
        font-size: 40px;
    }

    .card-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* Smartphone layout: one column */
@media screen and (max-width: 560px) {
    header {
        padding: 35px 20px;
    }

    header h1 {
        font-size: 32px;
    }

    nav {
        width: 100%;
        flex-direction: column;
    }

    nav a {
        width: 100%;
    }

    .card-grid {
        grid-template-columns: 1fr;
    }

    .card img {
        height: 190px;
    }

    .techniques {
        flex-direction: column;
        gap: 5px;
    }

    .information,
    .techniques {
        padding: 18px;
    }
}