:root {
    --primary: #2980b9;
    --primary-dark: #1c5980;
    --bg: #f4f6f9;
    --text: #2c3e50;
    --white: #fff;
}

body {
    font-family: 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg);
    color: var(--text);
    padding: 1rem;
    transition: background-color 0.4s, color 0.4s;
}

.container {
    max-width: 900px;
    margin: auto;
    background-color: var(--white);
    padding: 2rem;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.06);
    border-radius: 12px;
}

h2 {
    text-align: center;
    margin-bottom: 2rem;
}

/* Form stylé */
form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

input, textarea, select {
    padding: 0.75rem;
    border: 1px solid #ccc;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s;
}

input:focus, textarea:focus {
    border-color: var(--primary);
    outline: none;
}

button {
    background-color: var(--primary);
    color: white;
    border: none;
    padding: 0.75rem;
    font-weight: bold;
    border-radius: 8px;
    transition: background-color 0.3s;
    cursor: pointer;
}

button:hover {
    background-color: var(--primary-dark);
}

/* Navigation */
nav {
    text-align: center;
    margin-bottom: 2rem;
}
nav a {
    margin: 0 10px;
    text-decoration: none;
    color: var(--primary);
    font-weight: bold;
}
nav a:hover {
    text-decoration: underline;
}

/* Loader animé */
.loader {
    border: 5px solid #f3f3f3;
    border-top: 5px solid var(--primary);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: auto;
    display: none;
}
@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Dark mode */
body.dark {
    --bg: #1e1e1e;
    --text: #f1f1f1;
    --white: #2c2c2c;
    --primary: #3498db;
    --primary-dark: #217dbb;
}

.dark nav a {
    color: #66c2ff;
}

/* Toggle button */
.toggle-darkmode {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: var(--primary);
    color: white;
    border: none;
    padding: 0.6rem 1rem;
    border-radius: 8px;
    cursor: pointer;
}

/* Logo */
.logo {
    display: block;
    margin: 0 auto 2rem;
    max-width: 160px;
}

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }
    nav {
        display: flex;
        flex-direction: column;
        gap: 0.5rem;
    }
}