/* ==========================================================================
   Mathalab — feuille de style principale
   ========================================================================== */

/* ---------- Variables ---------- */
:root {
    /* Couleurs */
    --color-text: #ffffff;
    --color-text-inverse: #000000;
    --color-surface: #3d3d3d;
    --color-border: #e2e8f0;
    --color-btn-bg: transparent;
    --color-btn-bg-hover: #ffffff;
    --color-input-bg: transparent;
    --color-error: #db4040;

    /* Typographie */
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;

    /* Mise en page */
    --max-width: 1200px;
    --max-width-narrow: 800px;
    --radius: 8px;
    --radius-sm: 6px;

    /* Ombres */
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
    --shadow-hover: 0 10px 15px -3px rgba(0, 0, 0, 0.05);
}

/* ---------- Base ---------- */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: var(--font-sans);
}

body {
    background-image: url("../img/bgtexture.png");
    background-repeat: repeat;
    color: var(--color-text);
    line-height: 1.6;
}

/* ---------- En-tête & navigation ---------- */
header {
    background-color: var(--color-surface);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 1.2rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--color-text);
    letter-spacing: -0.05em;
    cursor: pointer;
}

nav ul {
    display: flex;
    list-style: none;
    gap: 2rem;
}

nav a {
    text-decoration: none;
    color: var(--color-text);
    font-weight: 500;
    transition: color 0.2s;
    cursor: pointer;
}

nav a:hover,
nav a.active {
    text-decoration: underline;
}

/* ---------- Accueil (hero) ---------- */
.hero {
    color: var(--color-text);
    padding: 2rem 1rem;
    text-align: center;
    border-bottom: none;
}

.hero-content {
    max-width: var(--max-width-narrow);
    margin: 0 auto;
}

.hero-logo {
    text-align: center;
}

.hero-logo img {
    width: 50%;
}

.hero h1 {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
    letter-spacing: -0.02em;
}

.hero p {
    font-size: 1.25rem;
    color: var(--color-text);
    margin-bottom: 2.5rem;
}

/* ---------- Boutons ---------- */
.btn {
    display: inline-block;
    background-color: var(--color-btn-bg);
    color: var(--color-text);
    padding: 0.85rem 2rem;
    border-radius: var(--radius-sm);
    text-decoration: none;
    font-weight: 600;
    transition: background-color 0.2s, transform 0.1s;
    border: 2px solid var(--color-text);
    cursor: pointer;
}

.btn:hover {
    background-color: var(--color-btn-bg-hover);
    color: var(--color-text-inverse);
    transform: translateY(-1px);
}

.btn-block {
    width: 100%;
}

.btn:disabled {
    cursor: wait;
    opacity: 0.6;
}

/* ---------- Mise en page ---------- */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 5rem 2rem;
}

section {
    border-bottom: 1px solid var(--color-border);
    padding: 4rem 0;
}

section:last-of-type {
    border-bottom: none;
}

h2 {
    font-size: 2.25rem;
    color: var(--color-text);
    margin-bottom: 3rem;
    text-align: center;
    font-weight: 700;
}

.grid-2 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.mb-2 {
    margin-bottom: 2rem;
}

.mt-2 {
    margin-top: 2rem;
}

/* ---------- Cartes ---------- */
.card {
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-hover);
}

.card h3 {
    color: var(--color-text);
    font-size: 1.25rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

.card p {
    color: var(--color-text);
    font-size: 0.95rem;
}

/* ---------- Encadrés contact & pages légales ---------- */
.contact-box,
.legal-box {
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 3rem;
    max-width: var(--max-width-narrow);
    margin: 0 auto;
}

.contact-intro {
    text-align: center;
    margin-bottom: 2rem;
    color: var(--color-text);
}

.contact-location {
    text-align: center;
}

.legal-box h3 {
    color: var(--color-text);
    font-size: 1.25rem;
    margin-top: 1.5rem;
    margin-bottom: 0.5rem;
}

.legal-box p,
.legal-box ul {
    margin-bottom: 1rem;
    color: var(--color-text);
}

.legal-box ul {
    padding-left: 1.5rem;
}

.text-link {
    text-decoration: underline;
    color: var(--color-text);
}

/* ---------- Formulaire ---------- */
.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--color-text);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    background-color: var(--color-input-bg);
    color: var(--color-text);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--color-text);
    opacity: 0.5;
}

.form-group textarea {
    resize: vertical;
    height: 150px;
}

/* Case à cocher « Recevoir une copie » */
.form-check {
    display: flex;
    align-items: flex-start;
    gap: 0.6rem;
    margin-bottom: 1.5rem;
}

.form-check input {
    flex-shrink: 0;
    width: 1.1rem;
    height: 1.1rem;
    margin-top: 0.2rem;
    accent-color: var(--color-text);
    cursor: pointer;
}

.form-check label {
    font-size: 0.95rem;
    cursor: pointer;
}

.form-success-copy {
    margin-top: 1rem;
    font-size: 0.9rem;
    opacity: 0.85;
}

/* Champ piège : invisible pour les humains, présent pour les robots */
.form-hp {
    position: absolute;
    left: -10000px;
    width: 1px;
    height: 1px;
    overflow: hidden;
}

.field-hint {
    margin-top: 0.5rem;
    font-size: 0.9rem;
}

.field-hint:empty {
    display: none;
}

.field-hint button {
    background: none;
    border: none;
    color: var(--color-text);
    font: inherit;
    text-decoration: underline;
    cursor: pointer;
    padding: 0;
}

/* Fichiers joints : liste des fichiers sélectionnés */
.file-list:empty,
.file-total:empty {
    display: none;
}

.form-group input[type="file"]:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.file-list {
    list-style: none;
    margin-top: 1rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
}

.file-list li {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0.6rem 0.75rem;
}

.file-list li + li {
    border-top: 1px solid var(--color-border);
}

.file-name {
    flex: 1;
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.file-size {
    font-size: 0.85rem;
    white-space: nowrap;
}

.file-remove {
    background: none;
    border: 1px solid var(--color-text);
    border-radius: var(--radius-sm);
    color: var(--color-text);
    font: inherit;
    font-size: 0.85rem;
    padding: 0.2rem 0.75rem;
    cursor: pointer;
    transition: background-color 0.2s;
}

.file-remove:hover {
    background-color: var(--color-btn-bg-hover);
    color: var(--color-text-inverse);
}

.file-total {
    margin-top: 0.5rem;
    font-size: 0.85rem;
}

.form-success {
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    padding: 2.5rem 2rem;
    margin-bottom: 1.5rem;
    text-align: center;
    color: var(--color-text);
}

.form-success:focus {
    outline: none;
}

.form-success h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
}

.form-success[hidden],
.contact-intro[hidden],
form[hidden] {
    display: none;
}

.form-status {
    margin-top: 1rem;
    text-align: center;
    color: var(--color-error);
}

.form-status:empty {
    display: none;
}

/* ---------- Pied de page ---------- */
footer {
    background-color: var(--color-surface);
    color: var(--color-text);
    padding: 3rem 2rem 2rem 2rem;
    font-size: 0.9rem;
}

.footer-content {
    max-width: var(--max-width);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 2rem;
    margin-bottom: 2rem;
    padding-bottom: 2rem;
}

.footer-links {
    margin-left: 0;
}

.footer-col h4 {
    color: var(--color-text);
    font-size: 1rem;
    margin-bottom: 1rem;
    display: flex;
}

.footer-col ul {
    list-style: none;
}

.footer-col ul li {
    margin-bottom: 0.5rem;
}

.footer-col ul li a {
    color: var(--color-text);
    text-decoration: none;
    cursor: pointer;
    transition: color 0.2s;
}

.footer-bottom {
    text-align: center;
    max-width: var(--max-width);
    margin: 0 auto;
}

/* ---------- Responsive ---------- */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.25rem;
    }

    nav ul {
        display: none;
    }
}