:root {
            --font: 'Inter', system-ui, sans-serif;
            --text: #1e293b;
            --text-light: #64748b;
            --text-muted: #94a3b8;
            --border: #e2e8f0;
            --radius: 14px;
            --indigo: #6366f1;
            --sky: #0ea5e9;
            --emerald: #10b981;
            --amber: #f59e0b;
            --violet: #8b5cf6;
            --rose: #f43f5e;
        }

        * { margin: 0; padding: 0; box-sizing: border-box; }
        html { scroll-behavior: smooth; }

        body {
            font-family: var(--font);
            min-height: 100vh;
            color: var(--text);
            line-height: 1.6;
            /* Dégradé linéaire subtil qui change selon l'étape via JS */
            background: linear-gradient(160deg, #f0f4ff 0%, #fff0f5 35%, #f0fff4 70%, #fffbeb 100%);
            background-attachment: fixed;
            transition: background 0.8s ease;
        }

        /* ═══════════════════════════════════════════
           PROGRESS STEPPER
        ═══════════════════════════════════════════ */
        .stepper-wrap {
            position: fixed;
            top: 0; left: 0; right: 0;
            z-index: 100;
            background: rgba(255,255,255,0.75);
            backdrop-filter: blur(10px);
            border-bottom: 1px solid rgba(226,232,240,0.5);
            padding: 16px 16px 12px;
        }
        .stepper {
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 0;
            max-width: 560px;
            margin: 0 auto;
        }
        .step-dot {
            width: 32px; height: 32px;
            border-radius: 50%;
            display: flex; align-items: center; justify-content: center;
            font-size: 0.78rem;
            font-weight: 700;
            flex-shrink: 0;
            transition: all 0.35s ease;
            border: 2px solid var(--border);
            background: #fff;
            color: var(--text-muted);
        }
        .step-dot.active {
            border-color: var(--indigo);
            background: var(--indigo);
            color: #fff;
            box-shadow: 0 0 0 4px rgba(99,102,241,0.15);
        }
        .step-dot.done {
            border-color: var(--emerald);
            background: var(--emerald);
            color: #fff;
        }
        .step-line {
            flex: 1;
            height: 2px;
            background: var(--border);
            margin: 0 4px;
            transition: background 0.4s ease;
            max-width: 60px;
        }
        .step-line.done {
            background: var(--emerald);
        }
        .step-labels {
            display: flex;
            justify-content: space-between;
            max-width: 560px;
            margin: 6px auto 0;
            padding: 0 4px;
        }
        .step-label {
            font-size: 0.65rem;
            font-weight: 500;
            color: var(--text-muted);
            text-align: center;
            width: 60px;
            line-height: 1.2;
            transition: color 0.3s;
        }
        .step-label.active { color: var(--indigo); font-weight: 600; }

        @media (max-width: 480px) {
            .step-label { font-size: 0.6rem; width: 48px; }
            .step-dot { width: 28px; height: 28px; font-size: 0.7rem; }
        }

        /* ═══════════════════════════════════════════
           LAYOUT
        ═══════════════════════════════════════════ */
        .container {
            max-width: 640px;
            margin: 0 auto;
            padding: 110px 16px 40px;
            min-height: 100vh;
            display: flex;
            flex-direction: column;
        }

        /* ═══════════════════════════════════════════
           CARD
        ═══════════════════════════════════════════ */
        .card {
            background: rgba(255,255,255,0.92);
            border-radius: var(--radius);
            border: 1px solid rgba(226,232,240,0.6);
            box-shadow: 0 4px 24px rgba(0,0,0,0.04);
            padding: 28px;
            flex: 1;
            display: none;
            animation: fadeIn 0.45s ease both;
        }
        .card.visible { display: block; }

        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(12px); }
            to   { opacity: 1; transform: translateY(0); }
        }

        .card-header {
            margin-bottom: 24px;
            padding-bottom: 16px;
            border-bottom: 1px solid var(--border);
        }
        .card-number {
            display: inline-block;
            font-size: 0.7rem;
            font-weight: 700;
            letter-spacing: 0.08em;
            text-transform: uppercase;
            color: var(--indigo);
            background: rgba(99,102,241,0.08);
            padding: 4px 10px;
            border-radius: 6px;
            margin-bottom: 8px;
        }
        .card-title {
            font-size: 1.25rem;
            font-weight: 700;
            letter-spacing: -0.01em;
            margin-bottom: 4px;
        }
        .card-desc {
            font-size: 0.9rem;
            color: var(--text-light);
            font-weight: 400;
        }

        /* ═══════════════════════════════════════════
           FIELDS
        ═══════════════════════════════════════════ */
        .field { margin-bottom: 22px; }
        .field:last-child { margin-bottom: 0; }

        label {
            display: block;
            font-size: 0.9rem;
            font-weight: 600;
            color: var(--text);
            margin-bottom: 6px;
        }
        .hint {
            display: block;
            font-size: 0.82rem;
            font-weight: 400;
            color: var(--text-muted);
            margin-top: 2px;
            margin-bottom: 8px;
            line-height: 1.5;
        }
        .required { color: var(--rose); margin-left: 2px; }

        input[type="text"],
        input[type="email"],
        input[type="number"],
        select,
        textarea {
            width: 100%;
            padding: 12px 14px;
            font-family: var(--font);
            font-size: 0.95rem;
            color: var(--text);
            background: #fff;
            border: 1.5px solid var(--border);
            border-radius: 10px;
            outline: none;
            transition: all 0.2s ease;
        }
        input:focus, select:focus, textarea:focus {
            border-color: #94a3b8;
            box-shadow: 0 0 0 3px rgba(99,102,241,0.08);
        }
        input.error, select.error, textarea.error {
            border-color: var(--rose);
            box-shadow: 0 0 0 3px rgba(244,63,94,0.08);
        }
        textarea { resize: vertical; min-height: 90px; }
        select {
            cursor: pointer;
            appearance: none;
            background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
            background-repeat: no-repeat;
            background-position: right 12px center;
            padding-right: 36px;
        }

        .grid-2 {
            display: grid;
            grid-template-columns: 1fr;
            gap: 16px;
        }
        @media (min-width: 560px) {
            .grid-2 { grid-template-columns: 1fr 1fr; }
        }

        /* Radio group */
        .radio-group {
            display: flex;
            flex-wrap: wrap;
            gap: 8px;
        }
        .radio-pill {
            position: relative;
        }
        .radio-pill input {
            position: absolute;
            opacity: 0;
            width: 0; height: 0;
        }
        .radio-pill label {
            display: inline-flex;
            align-items: center;
            gap: 6px;
            padding: 10px 18px;
            background: #fff;
            border: 1.5px solid var(--border);
            border-radius: 10px;
            font-size: 0.9rem;
            font-weight: 500;
            cursor: pointer;
            transition: all 0.2s ease;
            margin-bottom: 0;
        }
        .radio-pill input:checked + label {
            background: #eef2ff;
            border-color: var(--indigo);
            color: #4338ca;
        }
        .radio-pill label:hover {
            background: #f8fafc;
        }

        /* Conditional */
        .conditional {
            max-height: 0;
            overflow: hidden;
            opacity: 0;
            transition: all 0.35s ease;
        }
        .conditional.open {
            max-height: 300px;
            opacity: 1;
            margin-top: 12px;
        }

        /* ═══════════════════════════════════════════
           NAV BUTTONS
        ═══════════════════════════════════════════ */
        .nav-bar {
            display: flex;
            gap: 12px;
            margin-top: 28px;
            padding-top: 20px;
            border-top: 1px solid var(--border);
        }
        .btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: 8px;
            padding: 12px 24px;
            font-family: var(--font);
            font-size: 0.95rem;
            font-weight: 600;
            border-radius: 10px;
            cursor: pointer;
            transition: all 0.2s ease;
            border: none;
            outline: none;
        }
        .btn-primary {
            background: linear-gradient(135deg, var(--indigo), #818cf8);
            color: #fff;
            box-shadow: 0 4px 12px rgba(99,102,241,0.3);
            flex: 1;
        }
        .btn-primary:hover {
            transform: translateY(-1px);
            box-shadow: 0 6px 18px rgba(99,102,241,0.4);
        }
        .btn-primary:active { transform: translateY(0); }
        .btn-primary:disabled {
            opacity: 0.6;
            cursor: not-allowed;
            transform: none;
        }
        .btn-secondary {
            background: #fff;
            color: var(--text);
            border: 1.5px solid var(--border);
        }
        .btn-secondary:hover {
            background: #f8fafc;
            border-color: #cbd5e1;
        }

        .spinner {
            width: 16px; height: 16px;
            border: 2px solid rgba(255,255,255,0.4);
            border-top-color: #fff;
            border-radius: 50%;
            animation: spin 0.7s linear infinite;
            display: none;
        }
        .btn.loading .spinner { display: block; }

        @keyframes spin { to { transform: rotate(360deg); } }

        /* ═══════════════════════════════════════════
           STEP 6 — MERCI
        ═══════════════════════════════════════════ */
        .merci {
            text-align: center;
            padding: 40px 20px;
        }
        .merci-icon {
            width: 72px; height: 72px;
            margin: 0 auto 20px;
            background: linear-gradient(135deg, var(--emerald), #34d399);
            border-radius: 50%;
            display: flex; align-items: center; justify-content: center;
            box-shadow: 0 8px 24px rgba(16,185,129,0.25);
            animation: popIn 0.5s cubic-bezier(0.34,1.56,0.64,1) both 0.2s;
        }
        .merci-icon svg {
            width: 32px; height: 32px;
            stroke: #fff;
            stroke-width: 3;
            fill: none;
            stroke-linecap: round;
            stroke-linejoin: round;
        }
        .merci h2 {
            font-size: 1.5rem;
            font-weight: 700;
            margin-bottom: 8px;
            animation: fadeInUp 0.5s ease both 0.35s;
        }
        .merci p {
            color: var(--text-light);
            font-size: 0.95rem;
            max-width: 360px;
            margin: 0 auto 24px;
            animation: fadeInUp 0.5s ease both 0.45s;
        }
        .merci .btn-primary {
            animation: fadeInUp 0.5s ease both 0.55s;
            max-width: 240px;
            margin: 0 auto;
        }

        @keyframes popIn {
            from { opacity: 0; transform: scale(0.5); }
            to   { opacity: 1; transform: scale(1); }
        }
        @keyframes fadeInUp {
            from { opacity: 0; transform: translateY(16px); }
            to   { opacity: 1; transform: translateY(0); }
        }

        /* ═══════════════════════════════════════════
           TOAST
        ═══════════════════════════════════════════ */
        .toast {
            position: fixed;
            bottom: 20px;
            left: 50%;
            transform: translateX(-50%) translateY(120%);
            padding: 14px 22px;
            border-radius: 10px;
            font-size: 0.9rem;
            font-weight: 500;
            color: #fff;
            box-shadow: 0 8px 24px rgba(0,0,0,0.12);
            opacity: 0;
            transition: all 0.4s cubic-bezier(0.34,1.56,0.64,1);
            z-index: 200;
            white-space: nowrap;
        }
        .toast.show { transform: translateX(-50%) translateY(0); opacity: 1; }
        .toast.error { background: linear-gradient(135deg, var(--rose), #e11d48); }

        /* Honeypot */
        .hp { position: absolute; left: -9999px; }

        @media (max-width: 480px) {
            .card { padding: 20px; }
            .card-title { font-size: 1.1rem; }
            .nav-bar { flex-direction: column-reverse; }
            .btn { width: 100%; }
        }