:root {
    --blanc: #ffffff;
    --blanc-casse: #f7f9fc;
    --bleu-fonce: #102a43;
    --bleu-moyen: #1769aa;
    --bleu-pale: #008fe5;
    --texte: #243b53;
    --texte-doux: #52677a;
    --bordure: #d9e2ec;
    --largeur: 1200px;
}

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

html {
    scroll-behavior: smooth;
}

body {
    background: var(--blanc);
    color: var(--texte);
    font-family:
        "Segoe UI",
        Arial,
        sans-serif;
    line-height: 1.6;
}

a {
    color: inherit;
    text-decoration: none;
}

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


/* En-tête */

.site-header {
    position: sticky;
    top: 0;
    z-index: 1000;

    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 30px;

    min-height: 90px;
    padding: 12px max(30px, calc((100% - var(--largeur)) / 2));

    background: var(--blanc);
    border-bottom: 1px solid var(--bordure);
}

.logo img {
    width: 245px;
    max-height: 70px;
    object-fit: contain;
    object-position: left center;

    transform: scale(1.30);
    transform-origin: left center;
}

.navigation {
    display: flex;
    align-items: center;
    gap: 30px;
}

.navigation a {
    color: var(--bleu-fonce);
    font-weight: 600;
    transition:
        color 0.2s ease,
        border-color 0.2s ease;
}

.navigation a:hover {
    color: var(--bleu-pale);
}


/* Section principale */

.hero {
    display: flex;
    align-items: center;

    min-height: 610px;
    padding:
        90px
        max(30px, calc((100% - var(--largeur)) / 2));

    background:
        linear-gradient(
            90deg,
            rgba(255, 255, 255, 1) 0%,
            rgba(247, 249, 252, 1) 58%,
            rgba(0, 143, 229, 0.10) 100%
        );

    border-bottom: 5px solid var(--bleu-pale);
}

.hero-contenu {
    max-width: 760px;
}

.surtitre {
    margin-bottom: 12px;

    color: var(--bleu-pale);
    font-size: 0.9rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

h1,
h2,
h3 {
    color: var(--bleu-fonce);
    line-height: 1.2;
}

h1 {
    max-width: 750px;
    margin-bottom: 25px;
    font-size: clamp(2.5rem, 6vw, 5rem);
}

h2 {
    margin-bottom: 20px;
    font-size: clamp(2rem, 4vw, 3.2rem);
}

h3 {
    margin-bottom: 14px;
    font-size: 1.35rem;
}

.introduction {
    max-width: 680px;
    margin-bottom: 34px;

    color: var(--texte-doux);
    font-size: 1.2rem;
}


/* Boutons */

.bouton {
    display: inline-block;

    padding: 14px 24px;

    background: var(--bleu-fonce);
    color: var(--blanc);

    border: 2px solid var(--bleu-fonce);
    border-radius: 6px;

    font-weight: 700;

    transition:
        background 0.2s ease,
        color 0.2s ease,
        transform 0.2s ease;
}

.bouton:hover {
    background: var(--bleu-pale);
    border-color: var(--bleu-pale);
    transform: translateY(-2px);
}

.bouton-clair {
    background: var(--blanc);
    color: var(--bleu-fonce);
    border-color: var(--blanc);
}

.bouton-clair:hover {
    background: transparent;
    color: var(--blanc);
    border-color: var(--blanc);
}


/* Sections */

.section {
    padding:
        100px
        max(30px, calc((100% - var(--largeur)) / 2));
}

.section-claire {
    background: var(--blanc-casse);
}

.titre-section {
    max-width: 820px;
    margin-bottom: 50px;
}

.contenu-etroit {
    max-width: 800px;
}

.contenu-etroit p:last-child {
    color: var(--texte-doux);
    font-size: 1.15rem;
}


/* Services */

.grille-services {
    display: grid;
    grid-template-columns:
        repeat(2, minmax(0, 1fr));
    gap: 24px;
}

.carte-service {
    position: relative;

    min-height: 230px;
    padding: 32px;

    background: var(--blanc);
    border: 1px solid var(--bordure);
    border-radius: 10px;

    box-shadow:
        0 12px 30px rgba(16, 42, 67, 0.07);
}

.carte-service::before {
    position: absolute;
    top: 0;
    left: 0;

    width: 100%;
    height: 5px;

    background: var(--bleu-pale);

    border-radius: 10px 10px 0 0;

    content: "";
}

.carte-service p {
    color: var(--texte-doux);
}


/* Projet */

.projet {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 40px;

    padding: 40px;

    background: var(--blanc);
    border-left: 6px solid var(--bleu-pale);
    border-radius: 8px;

    box-shadow:
        0 12px 30px rgba(16, 42, 67, 0.07);
}

.projet div {
    max-width: 720px;
}

.etiquette {
    margin-bottom: 10px;

    color: var(--bleu-moyen);
    font-size: 0.85rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.lien-projet {
    flex-shrink: 0;

    color: var(--bleu-fonce);
    font-weight: 700;
    border-bottom: 2px solid var(--bleu-pale);
}


/* Contact */

.contact {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 40px;

    background: var(--bleu-fonce);
    color: var(--blanc);
}

.contact h2 {
    color: var(--blanc);
}

.contact div {
    max-width: 700px;
}


/* Pied de page */

.site-footer {
    padding: 25px 30px;

    background: #091d2e;
    color: #cbd5df;

    text-align: center;
}


/* Tablettes et téléphones */

@media (max-width: 850px) {

    .site-header {
    position: static;
    flex-direction: column;
    align-items: center;
    gap: 18px;
}

.navigation {
    width: 100%;

    display: flex;
    justify-content: center;
    flex-wrap: wrap;

    gap: 10px 18px;
    padding-bottom: 8px;

    overflow: visible;
}

    .hero {
        min-height: auto;
        padding-top: 75px;
        padding-bottom: 75px;
    }

    .grille-services {
        grid-template-columns: 1fr;
    }

    .projet,
    .contact {
        align-items: flex-start;
        flex-direction: column;
    }
}


@media (max-width: 520px) {

    .site-header,
    .hero,
    .section {
        padding-left: 20px;
        padding-right: 20px;
    }

    .logo img {
        width: 210px;
        transform: scale(1.05);
        transform-origin: center;
    }

    .navigation {
        font-size: 0.9rem;
    }

    .carte-service,
    .projet {
        padding: 25px;
    }
    h1 {
    font-size: 2.25rem;
    }

    h2 {
        font-size: 1.85rem;
    }

    .surtitre {
        font-size: 0.78rem;
        letter-spacing: 0.08em;
    }

    .hero {
        padding-top: 55px;
        padding-bottom: 55px;
    }
}