/* ======================================================
   SENTINEL BIKE AI 2027
   Site officiel
   Feuille de style principale
====================================================== */

:root{
    --background:#0b0f14;
    --surface:#151b22;
    --surface-light:#1d2630;
    --primary:#00c8ff;
    --primary-light:#7fdfff;
    --accent:#00ff99;
    --text:#ffffff;
    --text-muted:#c7d0d9;
    --border:rgba(0,200,255,.35);
    --shadow:0 16px 40px rgba(0,0,0,.28);
}

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

html{
    scroll-behavior:smooth;
}

body{
    min-height:100vh;
    font-family:Arial,Helvetica,sans-serif;
    background:
        radial-gradient(circle at top,rgba(0,200,255,.08),transparent 35rem),
        var(--background);
    color:var(--text);
    line-height:1.65;
}

a{
    color:inherit;
}

/* ================= HEADER ================= */

header{
    position:sticky;
    top:0;
    z-index:999;
    background:rgba(21,27,34,.96);
    border-bottom:3px solid var(--primary);
    box-shadow:0 8px 24px rgba(0,0,0,.24);
}

/* ================= NAVIGATION ================= */

nav{
    width:min(1400px,100%);
    margin:0 auto;
    display:flex;
    justify-content:space-between;
    align-items:center;
    gap:24px;
    padding:16px 24px;
}

.logo{
    flex-shrink:0;
    color:var(--primary);
    font-size:clamp(1.35rem,2.5vw,1.9rem);
    font-weight:800;
    line-height:1.15;
    text-decoration:none;
}

.nav-links{
    display:flex;
    justify-content:flex-end;
    align-items:center;
    flex-wrap:wrap;
    gap:6px;
}

nav a{
    color:var(--text);
    text-decoration:none;
    padding:10px 13px;
    border-radius:8px;
    font-weight:700;
    transition:background-color .25s,color .25s,transform .25s;
}

nav a:hover,
nav a:focus-visible,
nav a[aria-current="page"]{
    background:var(--primary);
    color:#001118;
}

nav a:hover{
    transform:translateY(-2px);
}

/* ================= HERO ================= */

.hero{
    min-height:650px;
    display:flex;
    flex-direction:column;
    justify-content:center;
    align-items:center;
    padding:100px 30px;
    text-align:center;
}

.eyebrow{
    width:fit-content;
    margin:0 auto 18px;
    padding:7px 16px;
    border:1px solid var(--border);
    border-radius:999px;
    color:var(--accent);
    background:rgba(0,255,153,.06);
    font-size:.95rem;
    font-weight:800;
    letter-spacing:.06em;
    text-transform:uppercase;
}

.hero h1{
    max-width:1050px;
    color:var(--primary);
    font-size:clamp(2.6rem,7vw,4.7rem);
    line-height:1.08;
    margin-bottom:20px;
    text-shadow:0 0 28px rgba(0,200,255,.22);
}

.slogan{
    color:var(--primary-light);
    font-size:clamp(1.25rem,3vw,1.75rem);
    font-weight:700;
    margin-bottom:25px;
}

.hero p{
    max-width:900px;
    margin-left:auto;
    margin-right:auto;
    color:var(--text-muted);
    font-size:clamp(1.05rem,2vw,1.25rem);
}

.hero-actions{
    display:flex;
    justify-content:center;
    flex-wrap:wrap;
    gap:16px;
    margin-top:40px;
}

/* ================= BOUTONS ================= */

.btn{
    display:inline-flex;
    justify-content:center;
    align-items:center;
    min-height:56px;
    padding:14px 30px;
    border:2px solid var(--primary);
    border-radius:12px;
    background:var(--primary);
    color:#001118;
    text-decoration:none;
    font-weight:800;
    box-shadow:0 10px 28px rgba(0,200,255,.18);
    transition:background-color .3s,border-color .3s,transform .3s;
}

.btn:hover,
.btn:focus-visible{
    background:var(--accent);
    border-color:var(--accent);
    transform:translateY(-3px);
}

.btn-secondary{
    background:transparent;
    color:var(--primary-light);
    box-shadow:none;
}

.btn-secondary:hover,
.btn-secondary:focus-visible{
    color:#001118;
}

/* ================= SECTIONS ================= */

main section{
    width:min(1200px,calc(100% - 40px));
    margin:0 auto;
    padding:80px 20px;
}

main section + section{
    border-top:1px solid var(--border);
}

section h2{
    color:var(--primary);
    text-align:center;
    font-size:clamp(2rem,4vw,2.7rem);
    line-height:1.2;
    margin-bottom:34px;
}

section p{
    max-width:1000px;
    margin-left:auto;
    margin-right:auto;
    color:var(--text-muted);
    font-size:1.12rem;
}

.project-intro{
    text-align:center;
}

/* ================= CARTES ================= */

.feature-grid{
    display:grid;
    grid-template-columns:repeat(3,minmax(0,1fr));
    gap:22px;
}

.feature-card{
    height:100%;
    padding:28px;
    border:1px solid var(--border);
    border-radius:16px;
    background:linear-gradient(145deg,var(--surface-light),var(--surface));
    box-shadow:var(--shadow);
    transition:transform .3s,border-color .3s;
}

.feature-card:hover{
    transform:translateY(-7px);
    border-color:var(--primary);
}

.feature-card h3{
    color:var(--primary-light);
    font-size:1.25rem;
    margin-bottom:12px;
}

.feature-card p{
    font-size:1rem;
}

/* ================= APERÇU TECHNIQUE ================= */

.technical-overview ul{
    max-width:850px;
    margin:30px auto;
    padding:28px 28px 28px 54px;
    border:1px solid var(--border);
    border-radius:16px;
    background:var(--surface);
}

.technical-overview li{
    margin:12px 0;
    color:var(--text-muted);
    font-size:1.08rem;
}

.technical-overview li::marker{
    color:var(--accent);
}

.notice{
    padding:22px 24px;
    border-left:5px solid var(--accent);
    border-radius:0 12px 12px 0;
    background:rgba(0,255,153,.07);
}

.notice strong{
    color:var(--accent);
}

/* ================= ÉTAPES DU PROTOTYPE ================= */

.roadmap-list{
    max-width:920px;
    margin:0 auto;
    list-style:none;
    counter-reset:prototype-step;
}

.roadmap-list li{
    position:relative;
    margin:0 0 18px 36px;
    padding:22px 24px 22px 54px;
    counter-increment:prototype-step;
    border:1px solid var(--border);
    border-radius:14px;
    background:var(--surface);
}

.roadmap-list li::before{
    content:counter(prototype-step);
    position:absolute;
    top:50%;
    left:-36px;
    width:58px;
    height:58px;
    display:grid;
    place-items:center;
    transform:translateY(-50%);
    border:4px solid var(--background);
    border-radius:50%;
    background:var(--primary);
    color:#001118;
    font-size:1.25rem;
    font-weight:900;
}

.roadmap-list strong{
    display:block;
    margin-bottom:5px;
    color:var(--primary-light);
    font-size:1.15rem;
}

.roadmap-list span{
    display:block;
    color:var(--text-muted);
    font-size:1rem;
}

/* ================= LIENS DU PROJET ================= */

.link-grid{
    display:grid;
    grid-template-columns:repeat(4,minmax(0,1fr));
    gap:18px;
}

.project-link{
    display:flex;
    justify-content:center;
    align-items:center;
    min-height:110px;
    padding:20px;
    border:1px solid var(--border);
    border-radius:14px;
    background:var(--surface);
    color:var(--primary-light);
    text-align:center;
    text-decoration:none;
    font-size:1.08rem;
    font-weight:800;
    transition:background-color .3s,color .3s,transform .3s;
}

.project-link:hover,
.project-link:focus-visible{
    background:var(--primary);
    color:#001118;
    transform:translateY(-5px);
}

/* ================= GALERIE ================= */

.gallery{
    display:grid;
    grid-template-columns:repeat(auto-fit,minmax(280px,1fr));
    gap:30px;
}

.gallery figure{
    padding:20px;
    border:1px solid var(--border);
    border-radius:14px;
    background:var(--surface);
    text-align:center;
    box-shadow:var(--shadow);
    transition:transform .3s;
}

.gallery figure:hover{
    transform:translateY(-8px);
}

.gallery img{
    display:block;
    width:100%;
    height:auto;
    border-radius:10px;
}

.gallery figcaption{
    margin-top:15px;
    color:var(--primary-light);
    font-weight:700;
}

.image-gallery figure{
    overflow:hidden;
}

.image-gallery figure > a{
    display:block;
    overflow:hidden;
    border-radius:10px;
    background:#090d11;
}

.image-gallery img{
    aspect-ratio:16 / 10;
    object-fit:contain;
    transition:transform .35s;
}

.image-gallery figure:hover img{
    transform:scale(1.035);
}

.document-gallery figure{
    display:flex;
    min-height:190px;
    flex-direction:column;
    justify-content:space-between;
    align-items:center;
}

.document-gallery figcaption{
    font-size:1.08rem;
}

.document-gallery .btn{
    width:100%;
    margin-top:24px;
}

/* ================= ACCESSIBILITÉ ================= */

a:focus-visible{
    outline:3px solid var(--accent);
    outline-offset:3px;
}

/* ================= FOOTER ================= */

footer{
    padding:35px 24px;
    border-top:3px solid var(--primary);
    background:var(--surface);
    color:var(--text-muted);
    text-align:center;
}

/* ================= RESPONSIVE ================= */

@media(max-width:1050px){
    nav{
        flex-direction:column;
    }

    .logo{
        width:100%;
        text-align:center;
    }

    .nav-links{
        justify-content:center;
    }

    .feature-grid{
        grid-template-columns:repeat(2,minmax(0,1fr));
    }

    .link-grid{
        grid-template-columns:repeat(2,minmax(0,1fr));
    }
}

@media(max-width:700px){
    header{
        position:relative;
    }

    nav{
        padding:16px;
    }

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

    nav a{
        width:100%;
        text-align:center;
    }

    .hero{
        min-height:auto;
        padding:70px 22px;
    }

    main section{
        width:min(100% - 24px,1200px);
        padding:58px 12px;
    }

    .feature-grid,
    .link-grid{
        grid-template-columns:1fr;
    }

    .hero-actions{
        width:100%;
        flex-direction:column;
    }

    .roadmap-list li{
        margin-left:25px;
        padding:22px 18px 22px 44px;
    }

    .roadmap-list li::before{
        left:-29px;
        width:50px;
        height:50px;
    }

    .btn{
        width:100%;
    }
}

@media(prefers-reduced-motion:reduce){
    html{
        scroll-behavior:auto;
    }

    *,
    *::before,
    *::after{
        transition:none !important;
    }
}