/* RESET & BASE */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Segoe UI', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f9f9f9;
    font-size: 16px;
}

a {
    color: #0056b3;
    text-decoration: none;
    transition: color 0.2s;
}

a:hover {
    color: #003d80;
    text-decoration: underline;
}

ul {
    list-style-type: none;
    padding-left: 0;
}

/* LAYOUT */
.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 20px;
    background-color: #fff;
    min-height: 100vh;
    box-shadow: 0 0 10px rgba(0,0,0,0.05);
}

/* HEADER */
header.main-header {
    margin-bottom: 40px;
    border-bottom: 2px solid #eee;
    padding-bottom: 20px;
}

.breadcrumbs {
    font-size: 0.9em;
    color: #666;
    margin-bottom: 10px;
}

.breadcrumbs a {
    color: #555;
}

.breadcrumbs .current {
    font-weight: bold;
    color: #333;
}

/* TYPOGRAPHY */
h1, h2, h3 {
    color: #2c3e50;
    margin-top: 1.5em;
    margin-bottom: 0.5em;
}

h1 {
    font-size: 2.2em;
    margin-top: 0;
    border-bottom: 3px solid #0056b3;
    padding-bottom: 10px;
    display: inline-block;
}

h2 {
    font-size: 1.6em;
    border-left: 5px solid #0056b3;
    padding-left: 10px;
}

h3 {
    font-size: 1.3em;
    color: #444;
}

p {
    margin-bottom: 1em;
    text-align: justify;
}

/* COMPONENTS */
.level-tag {
    display: inline-block;
    padding: 5px 12px;
    border-radius: 4px;
    font-weight: bold;
    font-size: 0.8em;
    text-transform: uppercase;
    color: #fff;
    margin-bottom: 20px;
    vertical-align: middle;
}

.level-debutant { background-color: #28a745; }
.level-intermediaire { background-color: #17a2b8; }
.level-avance { background-color: #fd7e14; }
.level-expert { background-color: #dc3545; }

.card {
    border: 1px solid #ddd;
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 20px;
    transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.card h3 {
    margin-top: 0;
}

/* NAVIGATION LINKS */
.nav-links {
    margin-top: 40px;
    padding-top: 20px;
    border-top: 1px solid #eee;
    display: flex;
    justify-content: space-between;
}

.nav-prev::before { content: "← "; }
.nav-next::after { content: " →"; }

/* REFERENCES SECTION */
.references {
    margin-top: 60px;
    padding: 20px;
    background-color: #f8f9fa;
    border-radius: 8px;
    border-left: 5px solid #6c757d;
}

.references h3 {
    margin-top: 0;
    font-size: 1.2em;
}

.references ul li {
    margin-bottom: 8px;
    padding-left: 20px;
    position: relative;
}

.references ul li::before {
    content: "•";
    position: absolute;
    left: 0;
    color: #6c757d;
}

/* HOME PAGE SPECIFIC */
.portal-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    margin-top: 30px;
}

.welcome-message {
    font-size: 1.2em;
    color: #555;
    margin-bottom: 40px;
}