:root {
            --bg: #0a0a0a;
            --bg-card: #111;
            --bg-card2: #161616;
            --border: #222;
            --border-hover: #333;
            --text: #e8e8e8;
            --text-muted: #888;
            --text-dim: #555;
            --accent: #d4a84a;
            --accent-dim: rgba(212, 168, 74, 0.12);
            --accent-border: rgba(212, 168, 74, 0.3);
            --danger: #ff4d4f;
            --success: #22c55e;
            --radius: 10px;
            --radius-sm: 6px;
        }

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

        body {
            font-family: 'Inter', 'Noto Sans JP', -apple-system, sans-serif;
            background: var(--bg);
            color: var(--text);
            min-height: 100vh;
        }

        /* Navbar */
        .navbar {
            display: flex;
            align-items: center;
            justify-content: space-between;
            padding: 16px 24px;
            background: rgba(10, 10, 10, 0.95);
            border-bottom: 1px solid var(--border);
            position: sticky;
            top: 0;
            z-index: 100;
            backdrop-filter: blur(12px);
            -webkit-backdrop-filter: blur(12px);
        }

        .nav-brand {
            font-family: 'Space Grotesk', sans-serif;
            font-weight: 700;
            font-size: 16px;
            letter-spacing: 1px;
            color: var(--accent);
            text-decoration: none;
        }

        .nav-back {
            font-size: 13px;
            color: var(--text-muted);
            text-decoration: none;
            display: flex;
            align-items: center;
            gap: 4px;
            transition: color 0.2s;
        }

        .nav-back:hover {
            color: var(--accent);
        }

        /* Main Container */
        .auth-container {
            max-width: 560px;
            margin: 40px auto;
            padding: 0 20px 60px;
        }

        .auth-title {
            font-size: 24px;
            font-weight: 800;
            text-align: center;
            margin-bottom: 8px;
        }

        .auth-subtitle {
            font-size: 13px;
            color: var(--text-muted);
            text-align: center;
            margin-bottom: 32px;
        }

        /* Auth Buttons */
        .auth-buttons {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 12px;
            margin-bottom: 24px;
        }

        .auth-btn {
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 10px;
            padding: 14px 16px;
            border-radius: var(--radius);
            font-size: 14px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.2s;
            border: 1px solid var(--border);
            background: var(--bg-card);
            color: var(--text);
        }

        .auth-btn:hover {
            border-color: var(--border-hover);
            background: var(--bg-card2);
        }

        .auth-btn.active {
            border-color: var(--accent);
            background: var(--accent-dim);
        }

        .auth-btn svg {
            width: 20px;
            height: 20px;
            flex-shrink: 0;
        }

        /* Divider */
        .divider {
            display: flex;
            align-items: center;
            gap: 12px;
            margin: 20px 0;
            font-size: 12px;
            color: var(--text-dim);
        }

        .divider::before,
        .divider::after {
            content: '';
            flex: 1;
            height: 1px;
            background: var(--border);
        }

        /* Email Auth Form */
        .email-auth-form {
            display: block;
            background: var(--bg-card);
            border: 1px solid var(--border);
            border-radius: var(--radius);
            padding: 24px;
            margin-bottom: 24px;
            animation: slideDown 0.3s ease;
        }

        .email-auth-form.show {
            display: block;
        }

        @keyframes slideDown {
            from {
                opacity: 0;
                transform: translateY(-8px);
            }

            to {
                opacity: 1;
                transform: translateY(0);
            }
        }





        /* Form Styles */
        .form-group {
            margin-bottom: 16px;
        }

        .form-label {
            display: block;
            font-size: 12px;
            font-weight: 600;
            color: var(--text-muted);
            margin-bottom: 6px;
        }

        .form-label .required {
            color: var(--danger);
            margin-left: 4px;
        }

        .form-input {
            width: 100%;
            padding: 12px 14px;
            background: var(--bg);
            border: 1px solid var(--border);
            border-radius: var(--radius-sm);
            color: var(--text);
            font-size: 14px;
            font-family: inherit;
            transition: border-color 0.2s;
        }

        .form-input:focus {
            outline: none;
            border-color: var(--accent);
        }

        .form-input.error {
            border-color: var(--danger);
        }

        .field-error {
            font-size: 11px;
            color: var(--danger);
            margin-top: 4px;
            display: none;
        }

        /* Step Sections */
        .step-section {
            display: none;
            animation: fadeIn 0.3s ease;
        }

        .step-section.active {
            display: block;
        }

        @keyframes fadeIn {
            from {
                opacity: 0;
            }

            to {
                opacity: 1;
            }
        }

        .section-label {
            font-size: 14px;
            font-weight: 700;
            color: var(--accent);
            margin-bottom: 16px;
            padding-bottom: 8px;
            border-bottom: 1px solid var(--border);
        }

        /* Category Grid */
        .category-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
            gap: 8px;
            margin-bottom: 24px;
        }

        .category-option {
            padding: 14px 8px;
            text-align: center;
            font-size: 13px;
            font-weight: 600;
            border: 1px solid var(--border);
            border-radius: var(--radius-sm);
            cursor: pointer;
            transition: all 0.2s;
            background: var(--bg-card);
            color: var(--text-muted);
        }

        .category-option:hover {
            border-color: var(--border-hover);
            color: var(--text);
        }

        .category-option.selected {
            border-color: var(--accent);
            background: var(--accent-dim);
            color: var(--accent);
        }

        /* Survey Styles */
        .survey-section {
            display: none;
            margin-top: 16px;
        }

        .survey-section.active {
            display: block;
        }

        .survey-question {
            margin-bottom: 20px;
        }

        .survey-question-label {
            font-size: 13px;
            font-weight: 600;
            margin-bottom: 8px;
            color: var(--text);
        }

        .survey-options {
            display: flex;
            flex-wrap: wrap;
            gap: 8px;
        }

        .survey-option {
            padding: 8px 14px;
            font-size: 12px;
            border: 1px solid var(--border);
            border-radius: 20px;
            cursor: pointer;
            transition: all 0.2s;
            background: var(--bg-card);
            color: var(--text-muted);
        }

        .survey-option:hover {
            border-color: var(--border-hover);
        }

        .survey-option.selected {
            border-color: var(--accent);
            background: var(--accent-dim);
            color: var(--accent);
        }

        .survey-radio {
            display: flex;
            flex-direction: column;
            gap: 6px;
        }

        .survey-radio-item {
            padding: 10px 14px;
            font-size: 13px;
            border: 1px solid var(--border);
            border-radius: var(--radius-sm);
            cursor: pointer;
            transition: all 0.2s;
            background: var(--bg-card);
            color: var(--text-muted);
        }

        .survey-radio-item:hover {
            border-color: var(--border-hover);
        }

        .survey-radio-item.selected {
            border-color: var(--accent);
            background: var(--accent-dim);
            color: var(--accent);
        }

        .survey-textarea {
            width: 100%;
            min-height: 60px;
            padding: 10px 12px;
            background: var(--bg);
            border: 1px solid var(--border);
            border-radius: var(--radius-sm);
            color: var(--text);
            font-size: 13px;
            font-family: inherit;
            resize: vertical;
            margin-top: 8px;
        }

        .survey-textarea:focus {
            outline: none;
            border-color: var(--accent);
        }

        .survey-conditional {
            display: none;
        }

        .survey-conditional.show {
            display: block;
        }

        /* Buttons */
        .btn-primary {
            width: 100%;
            padding: 14px;
            font-size: 15px;
            font-weight: 700;
            border: none;
            background: var(--accent);
            color: #000;
            border-radius: var(--radius);
            cursor: pointer;
            transition: all 0.2s;
        }

        .btn-primary:hover {
            opacity: 0.9;
            transform: translateY(-1px);
        }

        .btn-primary:disabled {
            opacity: 0.4;
            cursor: not-allowed;
            transform: none;
        }

        .btn-secondary {
            width: 100%;
            padding: 12px;
            font-size: 14px;
            font-weight: 600;
            border: 1px solid var(--border);
            background: transparent;
            color: var(--text-muted);
            border-radius: var(--radius);
            cursor: pointer;
            transition: all 0.2s;
        }

        .btn-secondary:hover {
            border-color: var(--border-hover);
            color: var(--text);
        }

        .btn-row {
            display: flex;
            gap: 12px;
            margin-top: 24px;
        }

        .btn-row button {
            flex: 1;
        }

        /* Step indicator */
        .step-indicator {
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 8px;
            margin-bottom: 28px;
        }

        .step-dot {
            width: 28px;
            height: 4px;
            border-radius: 2px;
            background: var(--border);
            transition: all 0.3s;
        }

        .step-dot.active {
            background: var(--accent);
            width: 40px;
        }

        .step-dot.done {
            background: var(--success);
        }

        /* Message */
        .msg {
            margin-top: 12px;
            font-size: 13px;
            text-align: center;
            min-height: 20px;
        }

        .msg.error {
            color: var(--danger);
        }

        .msg.success {
            color: var(--success);
        }

        /* Success Screen */
        .success-screen {
            text-align: center;
            padding: 40px 0;
        }

        .success-icon {
            width: 64px;
            height: 64px;
            border-radius: 50%;
            background: rgba(34, 197, 94, 0.15);
            color: var(--success);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 28px;
            margin: 0 auto 20px;
        }

        .success-screen h3 {
            font-size: 20px;
            margin-bottom: 8px;
        }

        .success-screen p {
            font-size: 13px;
            color: var(--text-muted);
            margin-bottom: 24px;
        }

        /* Login link */
        .login-switch {
            text-align: center;
            margin-top: 20px;
            font-size: 13px;
            color: var(--text-muted);
        }

        .login-switch a {
            color: var(--accent);
            text-decoration: none;
            font-weight: 600;
        }

        .login-switch a:hover {
            text-decoration: underline;
        }

        /* Loading spinner */
        .spinner {
            width: 18px;
            height: 18px;
            border: 2px solid transparent;
            border-top-color: #000;
            border-radius: 50%;
            animation: spin 0.6s linear infinite;
            display: inline-block;
            vertical-align: middle;
        }

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

        /* Responsive */
        @media (max-width: 480px) {
            .navbar {
                padding: 12px 14px;
            }

            .nav-brand {
                font-size: 13px;
            }

            .nav-back {
                font-size: 12px;
            }

            .auth-buttons {
                grid-template-columns: 1fr;
            }

            .category-grid {
                grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
            }

            .auth-container {
                padding: 0 16px 40px;
                margin: 24px auto;
            }

            .auth-title {
                font-size: 20px;
            }

            .auth-subtitle {
                font-size: 12px;
                margin-bottom: 24px;
            }

            .form-input {
                font-size: 16px;
                /* Prevent iOS zoom on focus */
                padding: 12px;
            }

            .survey-textarea {
                font-size: 16px;
            }

            .btn-primary {
                padding: 14px;
                font-size: 15px;
            }

            .btn-secondary {
                padding: 12px;
                font-size: 14px;
            }

            .email-auth-form {
                padding: 18px;
            }

            .section-label {
                font-size: 13px;
            }

            .survey-option {
                padding: 7px 12px;
                font-size: 11px;
            }

            .survey-radio-item {
                padding: 10px 12px;
                font-size: 12px;
            }

            .success-screen h3 {
                font-size: 18px;
            }

            .success-screen p {
                font-size: 12px;
            }
        }