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

        :root {
            --bg: #f5f4f1;
            --surface: #ffffff;
            --surface-2: #f9f8f6;
            --border: rgba(0,0,0,0.07);
            --border-strong: rgba(0,0,0,0.12);
            --text-1: #1a1917;
            --text-2: #6b6a67;
            --text-3: #a09f9c;
            --accent: #1a1917;
            --accent-fg: #ffffff;
            --green: #2d6a4f;
            --green-bg: #d8f3dc;
            --red: #9b2226;
            --red-bg: #ffe8e8;
            --blue: #1d4e89;
            --blue-bg: #dbe9f9;
            --amber: #7d4e00;
            --amber-bg: #fff3cd;
            --radius-sm: 8px;
            --radius: 12px;
            --radius-lg: 16px;
            --radius-xl: 20px;
            --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
            --shadow-md: 0 4px 12px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.04);
            --font: 'DM Sans', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
            --mono: 'DM Mono', 'Courier New', monospace;
            --transition: 0.18s ease;
        }

        body {
            font-family: var(--font);
            background: var(--bg);
            color: var(--text-1);
            min-height: 100vh;
            padding: 32px 20px 64px;
            line-height: 1.5;
            -webkit-font-smoothing: antialiased;
        }

        .page-wrap {
            max-width: 920px;
            margin: 0 auto;
        }

        .browser-tabs {
            display: flex;
            gap: 8px;
            margin-bottom: 14px;
            overflow-x: auto;
            padding-bottom: 4px;
        }

        .browser-tab {
            border: 1px solid var(--border-strong);
            background: var(--surface);
            color: var(--text-2);
            border-radius: 14px 14px 0 0;
            padding: 10px 16px;
            cursor: pointer;
            white-space: nowrap;
            font-size: 13px;
            transition: all var(--transition);
            text-decoration: none;
            font-family: inherit;
            display: inline-flex;
            align-items: center;
            gap: 6px;
        }

        .browser-tab.active {
            background: var(--text-1);
            color: var(--accent-fg);
            border-color: var(--text-1);
            box-shadow: var(--shadow-md);
        }

        .tab-panel { display: none; }
        .tab-panel.active { display: block; }

        /* ── Header ── */
        .site-header {
            display: flex;
            align-items: center;
            gap: 14px;
            margin-bottom: 28px;
        }

        .logo-mark {
            width: 42px;
            height: 42px;
            background: var(--text-1);
            border-radius: var(--radius);
            display: flex;
            align-items: center;
            justify-content: center;
            color: #fff;
            font-size: 18px;
            flex-shrink: 0;
        }

        .site-header h1 {
            font-size: 20px;
            font-weight: 500;
            letter-spacing: -0.3px;
        }

        .site-header p {
            font-size: 13px;
            color: var(--text-2);
            margin-top: 1px;
        }

        /* ── Card ── */
        .card {
            background: var(--surface);
            border: 1px solid var(--border);
            border-radius: var(--radius-xl);
            padding: 22px 24px;
            margin-bottom: 12px;
            box-shadow: var(--shadow);
        }

        .card-header {
            display: flex;
            align-items: center;
            justify-content: space-between;
            margin-bottom: 18px;
        }

        .card-title {
            display: flex;
            align-items: center;
            gap: 8px;
            font-size: 13px;
            font-weight: 500;
            color: var(--text-2);
            letter-spacing: 0.02em;
        }

        .card-title i {
            font-size: 12px;
            opacity: 0.6;
        }

        .card-actions {
            display: flex;
            gap: 6px;
        }

        /* ── Form elements ── */
        .field {
            margin-bottom: 14px;
        }

        .field:last-child {
            margin-bottom: 0;
        }

        .field label {
            display: block;
            font-size: 12px;
            font-weight: 500;
            color: var(--text-2);
            margin-bottom: 6px;
        }

        .input-wrap {
            position: relative;
        }

        .input-icon {
            position: absolute;
            left: 12px;
            top: 50%;
            transform: translateY(-50%);
            color: var(--text-3);
            font-size: 13px;
            pointer-events: none;
        }

        input[type="text"],
        input[type="email"],
        input[type="number"],
        input[type="password"],
        select {
            width: 100%;
            height: 40px;
            padding: 0 12px;
            border: 1px solid var(--border-strong);
            border-radius: var(--radius-sm);
            background: var(--surface-2);
            font-family: var(--font);
            font-size: 14px;
            color: var(--text-1);
            outline: none;
            transition: border-color var(--transition), background var(--transition), box-shadow var(--transition);
            -webkit-appearance: none;
        }

        input[type="text"].with-icon,
        input[type="email"].with-icon,
        input[type="number"].with-icon,
        input[type="password"].with-icon {
            padding-left: 36px;
        }

        input:focus, select:focus {
            border-color: var(--text-1);
            background: var(--surface);
            box-shadow: 0 0 0 3px rgba(26,25,23,0.06);
        }

        input::placeholder {
            color: var(--text-3);
        }

        select {
            cursor: pointer;
            background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%236b6a67' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
            background-repeat: no-repeat;
            background-position: right 12px center;
            padding-right: 32px;
        }

        .field-row {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 12px;
        }

        /* ── Buttons ── */
        .btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: 6px;
            height: 32px;
            padding: 0 14px;
            border: 1px solid var(--border-strong);
            border-radius: var(--radius-sm);
            background: var(--surface);
            font-family: var(--font);
            font-size: 12px;
            font-weight: 500;
            color: var(--text-1);
            cursor: pointer;
            transition: background var(--transition), border-color var(--transition), transform var(--transition);
            white-space: nowrap;
            text-decoration: none;
        }

        .btn:hover {
            background: var(--surface-2);
        }

        .btn:active {
            transform: scale(0.97);
        }

        .btn i {
            font-size: 11px;
        }

        .btn-primary {
            width: 100%;
            height: 44px;
            background: var(--text-1);
            color: #fff;
            border-color: var(--text-1);
            border-radius: var(--radius);
            font-size: 14px;
            font-weight: 500;
            margin-top: 6px;
        }

        .btn-primary:hover {
            background: #333;
            border-color: #333;
        }

        .btn-primary:disabled {
            opacity: 0.5;
            cursor: not-allowed;
        }

        .btn-danger {
            color: var(--red);
            border-color: rgba(155,34,38,0.2);
        }

        .btn-danger:hover {
            background: var(--red-bg);
        }

        .btn-ghost {
            border-color: transparent;
            background: transparent;
        }

        .btn-ghost:hover {
            background: var(--surface-2);
            border-color: var(--border);
        }

        /* ── Toggle ── */
        .toggle-row {
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .toggle-row span {
            font-size: 13px;
            color: var(--text-1);
        }

        .toggle-switch {
            position: relative;
            width: 38px;
            height: 22px;
            flex-shrink: 0;
        }

        .toggle-switch input {
            opacity: 0;
            width: 0;
            height: 0;
            position: absolute;
        }

        .toggle-track {
            position: absolute;
            inset: 0;
            background: var(--border-strong);
            border-radius: 11px;
            transition: background var(--transition);
            cursor: pointer;
        }

        .toggle-thumb {
            position: absolute;
            width: 18px;
            height: 18px;
            border-radius: 50%;
            background: #fff;
            top: 2px;
            left: 2px;
            transition: left var(--transition);
            box-shadow: 0 1px 3px rgba(0,0,0,0.2);
            pointer-events: none;
        }

        .toggle-switch input:checked ~ .toggle-track {
            background: var(--green);
        }

        .toggle-switch input:checked ~ .toggle-thumb {
            left: 18px;
        }

        /* ── Status indicator ── */
        .status-pill {
            display: inline-flex;
            align-items: center;
            gap: 6px;
            padding: 4px 10px;
            border-radius: 999px;
            font-size: 12px;
            font-weight: 500;
        }

        .status-pill.active {
            background: var(--green-bg);
            color: var(--green);
        }

        .status-pill .dot {
            width: 6px;
            height: 6px;
            border-radius: 50%;
            background: currentColor;
        }

        /* ── Info bar ── */
        .info-bar {
            display: flex;
            align-items: flex-start;
            gap: 10px;
            padding: 12px 14px;
            border-radius: var(--radius-sm);
            font-size: 13px;
            line-height: 1.5;
        }

        .info-bar i {
            margin-top: 1px;
            flex-shrink: 0;
            font-size: 13px;
        }

        .info-bar.tip {
            background: var(--blue-bg);
            color: var(--blue);
        }

        .info-bar.warn {
            background: var(--amber-bg);
            color: var(--amber);
        }

        .info-bar a {
            color: inherit;
            font-weight: 500;
            text-decoration: underline;
            text-underline-offset: 2px;
            cursor: pointer;
        }

        /* ── Divider ── */
        .divider {
            height: 1px;
            background: var(--border);
            margin: 18px 0;
        }

        /* ── Alerts ── */
        .alert {
            display: none;
            align-items: center;
            gap: 10px;
            padding: 12px 16px;
            border-radius: var(--radius);
            font-size: 13px;
            margin-bottom: 12px;
            animation: fadeIn 0.2s ease;
        }

        .alert.show {
            display: flex;
        }

        .alert-error {
            background: var(--red-bg);
            color: var(--red);
            border: 1px solid rgba(155,34,38,0.15);
        }

        .alert-success {
            background: var(--green-bg);
            color: var(--green);
            border: 1px solid rgba(45,106,79,0.15);
        }

        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(-4px); }
            to { opacity: 1; transform: translateY(0); }
        }

        /* ── Loading ── */
        .loading-state {
            display: none;
            align-items: center;
            justify-content: center;
            gap: 12px;
            padding: 24px;
            font-size: 14px;
            color: var(--text-2);
        }

        .loading-state.show {
            display: flex;
        }

        .spinner {
            width: 20px;
            height: 20px;
            border: 2px solid var(--border-strong);
            border-top-color: var(--text-1);
            border-radius: 50%;
            animation: spin 0.8s linear infinite;
            flex-shrink: 0;
        }

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

        /* ── Result ── */
        .result-card {
            display: none;
            background: var(--surface);
            border: 1px solid var(--border);
            border-radius: var(--radius-xl);
            overflow: hidden;
            margin-bottom: 12px;
            box-shadow: var(--shadow);
            animation: fadeIn 0.2s ease;
        }

        .result-card.show {
            display: block;
        }

        .result-header {
            padding: 16px 20px;
            background: var(--surface-2);
            border-bottom: 1px solid var(--border);
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .result-header i {
            color: var(--green);
        }

        .result-header span {
            font-size: 14px;
            font-weight: 500;
        }

        .result-count {
            margin-left: auto;
            display: inline-flex;
            align-items: center;
            height: 20px;
            padding: 0 8px;
            background: var(--green-bg);
            color: var(--green);
            border-radius: 999px;
            font-size: 11px;
            font-weight: 500;
        }

        .result-body {
            padding: 16px 20px;
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: 16px;
        }

        .result-filename {
            font-size: 14px;
            font-weight: 500;
            margin-bottom: 2px;
        }

        .result-meta {
            font-size: 12px;
            color: var(--text-2);
        }

        .result-actions {
            display: flex;
            gap: 8px;
            flex-shrink: 0;
        }

        /* ── Lists ── */
        .list-container {
            border: 1px solid var(--border);
            border-radius: var(--radius);
            overflow: hidden;
        }

        .list-item {
            display: flex;
            align-items: center;
            gap: 12px;
            padding: 14px 16px;
            border-bottom: 1px solid var(--border);
            transition: background var(--transition);
        }

        .list-item:last-child {
            border-bottom: none;
        }

        .list-item:hover {
            background: var(--surface-2);
        }

        .list-icon {
            width: 34px;
            height: 34px;
            border-radius: var(--radius-sm);
            background: var(--surface-2);
            border: 1px solid var(--border);
            display: flex;
            align-items: center;
            justify-content: center;
            flex-shrink: 0;
            font-size: 14px;
            color: var(--text-2);
        }

        .list-info {
            flex: 1;
            min-width: 0;
        }

        .list-name {
            font-size: 13px;
            font-weight: 500;
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
            margin-bottom: 2px;
        }

        .list-meta {
            font-size: 11px;
            color: var(--text-3);
        }

        .list-actions {
            display: flex;
            gap: 6px;
            flex-shrink: 0;
        }

        .empty-state {
            padding: 36px 20px;
            text-align: center;
            color: var(--text-3);
        }

        .empty-state i {
            font-size: 28px;
            margin-bottom: 10px;
            display: block;
            opacity: 0.4;
        }

        .empty-state p {
            font-size: 13px;
        }

        /* ── Code block ── */
        .code-block {
            background: var(--surface-2);
            border: 1px solid var(--border);
            border-radius: var(--radius-sm);
            padding: 12px 14px;
            font-family: var(--mono);
            font-size: 12px;
            color: var(--text-2);
            line-height: 1.7;
            white-space: pre-wrap;
            word-break: break-all;
            margin: 10px 0;
        }

        /* ── Badge ── */
        .badge {
            display: inline-flex;
            align-items: center;
            height: 18px;
            padding: 0 7px;
            border-radius: 999px;
            font-size: 11px;
            font-weight: 500;
            background: var(--surface-2);
            border: 1px solid var(--border);
            color: var(--text-2);
            margin-left: 6px;
        }

        /* ── SMTP grid ── */
        .smtp-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 12px;
        }

        .smtp-actions {
            display: flex;
            gap: 8px;
            margin-top: 14px;
        }

        /* ── Record toggle ── */
        .record-toggle {
            display: flex;
            align-items: center;
            gap: 8px;
        }

        /* ── Modal ── */
        .modal-bg {
            display: none;
            position: fixed;
            inset: 0;
            background: rgba(0,0,0,0.35);
            backdrop-filter: blur(4px);
            z-index: 9999;
            align-items: center;
            justify-content: center;
            padding: 20px;
        }

        .modal-bg.show {
            display: flex;
        }

        .modal {
            background: var(--surface);
            border-radius: var(--radius-xl);
            width: 100%;
            max-width: 600px;
            max-height: 85vh;
            display: flex;
            flex-direction: column;
            box-shadow: 0 20px 60px rgba(0,0,0,0.15);
            animation: modalIn 0.22s ease;
        }

        @keyframes modalIn {
            from { opacity: 0; transform: translateY(12px) scale(0.97); }
            to { opacity: 1; transform: translateY(0) scale(1); }
        }

        .modal-head {
            display: flex;
            align-items: center;
            justify-content: space-between;
            padding: 18px 22px;
            border-bottom: 1px solid var(--border);
            flex-shrink: 0;
        }

        .modal-head h3 {
            font-size: 16px;
            font-weight: 500;
        }

        .modal-close {
            width: 30px;
            height: 30px;
            border-radius: var(--radius-sm);
            border: 1px solid var(--border);
            background: transparent;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 14px;
            color: var(--text-2);
            transition: background var(--transition);
        }

        .modal-close:hover {
            background: var(--surface-2);
        }

        .modal-body {
            padding: 20px 22px;
            overflow-y: auto;
            flex: 1;
        }

        .modal-foot {
            padding: 16px 22px;
            border-top: 1px solid var(--border);
            display: flex;
            justify-content: flex-end;
            gap: 8px;
            flex-shrink: 0;
        }

        .tips-list {
            list-style: none;
            margin-top: 14px;
        }

        .tips-list li {
            padding: 12px 14px;
            background: var(--surface-2);
            border-radius: var(--radius-sm);
            font-size: 13px;
            line-height: 1.6;
            margin-bottom: 8px;
            border-left: 3px solid var(--border-strong);
        }

        .tips-list li strong {
            display: block;
            margin-bottom: 3px;
            font-size: 12px;
            color: var(--text-2);
            font-weight: 500;
        }

        /* Preview modal content */
        .preview-content {
            background: var(--surface-2);
            border: 1px solid var(--border);
            border-radius: var(--radius-sm);
            padding: 14px;
            font-family: var(--mono);
            font-size: 12px;
            line-height: 1.7;
            white-space: pre-wrap;
            word-break: break-all;
            max-height: 360px;
            overflow-y: auto;
        }

        /* ── Help FAB ── */
        .help-fab {
            position: fixed;
            bottom: 24px;
            right: 24px;
            width: 44px;
            height: 44px;
            border-radius: 50%;
            background: var(--text-1);
            color: #fff;
            border: none;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 16px;
            box-shadow: var(--shadow-md);
            transition: transform var(--transition);
            z-index: 100;
        }

        .help-fab:hover {
            transform: scale(1.08);
        }

        /* ── Cleanup controls ── */
        .cleanup-bar {
            display: flex;
            align-items: center;
            gap: 8px;
            margin-bottom: 12px;
            flex-wrap: wrap;
        }

        .cleanup-bar span {
            font-size: 12px;
            color: var(--text-2);
        }

        .cleanup-bar select {
            height: 32px;
            width: auto;
            font-size: 12px;
            padding: 0 28px 0 10px;
        }

        /* ── History items ── */
        .history-item {
            display: flex;
            align-items: flex-start;
            gap: 12px;
            padding: 10px 14px;
            border-bottom: 1px solid var(--border);
            font-size: 12px;
        }

        .history-item:last-child {
            border-bottom: none;
        }

        .history-item.success { background: #f6fdf8; }
        .history-item.error { background: #fdf6f6; }

        .history-time {
            color: var(--text-3);
            min-width: 130px;
            flex-shrink: 0;
        }

        .history-msg {
            flex: 1;
            color: var(--text-2);
        }

        .history-count {
            color: var(--green);
            font-weight: 500;
        }

        /* ── Responsive ── */
        @media (max-width: 600px) {
            .field-row,
            .smtp-grid {
                grid-template-columns: 1fr;
            }

            .result-body {
                flex-direction: column;
                align-items: flex-start;
            }

            .result-actions {
                width: 100%;
            }

            .list-item {
                flex-wrap: wrap;
            }

            .list-actions {
                width: 100%;
                justify-content: flex-end;
            }

            .card-header {
                flex-wrap: wrap;
                gap: 10px;
            }
        }