:root {
        --tech-bg: #f4f7fb;
        --tech-panel: #ffffff;
        --tech-panel-2: #f8fafc;
        --tech-line: #e2e8f0;
        --tech-text: #0f172a;
        --tech-text-2: #64748b;
        --tech-accent: #0ea5e9;
        --tech-accent-2: #6366f1;
        --tech-accent-strong: #0284c7;
    }

    [v-cloak] {
        display: none;
    }

    .sq-app {
        min-height: 70vh;
        padding: 32px 0 56px;
        box-sizing: border-box;
        color: var(--tech-text);
        background-color: var(--tech-bg);
        background-image:
            radial-gradient(900px 420px at 12% -8%, rgba(14, 165, 233, .12), transparent 60%),
            radial-gradient(760px 420px at 88% 0%, rgba(99, 102, 241, .12), transparent 62%),
            linear-gradient(rgba(15, 23, 42, .045) 1px, transparent 1px),
            linear-gradient(90deg, rgba(15, 23, 42, .045) 1px, transparent 1px);
        background-size: auto, auto, 32px 32px, 32px 32px;
        /* 覆盖 Element Plus 主色，使 el-radio-button / el-pagination 融入主题 */
        --el-color-primary: var(--tech-accent);
        --el-color-primary-light-3: #7cc4fa;
        --el-color-primary-light-5: #b3dbfc;
        --el-color-primary-light-7: #d9ecfd;
        --el-color-primary-light-8: #ecf5ff;
        --el-color-primary-dark-2: #0284c7;
    }

    .sq-header {
        margin-bottom: 24px;
    }

    .sq-title {
        margin: 0;
        font-size: 26px;
        font-weight: 700;
        color: var(--tech-text);
        letter-spacing: .2px;
        display: flex;
        align-items: center;
        gap: 12px;
    }

    .sq-title::before {
        content: '';
        display: inline-block;
        width: 5px;
        height: 26px;
        border-radius: 3px;
        background: linear-gradient(180deg, var(--tech-accent) 0%, var(--tech-accent-2) 100%);
    }

    .filter-panel {
        background: var(--tech-panel);
        border: 1px solid var(--tech-line);
        border-radius: 16px;
        box-shadow: 0 12px 32px rgba(15, 23, 42, .08);
        padding: 20px 22px;
        margin-bottom: 24px;
    }

    .filter-row {
        display: flex;
        align-items: center;
        flex-wrap: wrap;
        gap: 12px;
    }

    .filter-row+.filter-row {
        margin-top: 14px;
    }

    .filter-label {
        width: 76px;
        flex-shrink: 0;
        font-size: 14px;
        font-weight: 600;
        color: var(--tech-text-2);
    }

    .filter-options {
        flex: 1;
        min-width: 0;
    }

    .filter-options .el-radio-group {
        flex-wrap: wrap;
    }

    .list-wrap {
        position: relative;
        min-height: 240px;
    }

    .paper-grid {
        display: grid;
        grid-template-columns: repeat(4, 1fr);
        gap: 20px;
    }

    .paper-card {
        background: var(--tech-panel);
        border: 1px solid var(--tech-line);
        border-radius: 16px;
        box-shadow: 0 2px 12px rgba(15, 23, 42, .04);
        padding: 20px;
        display: flex;
        flex-direction: column;
        gap: 12px;
        cursor: pointer;
        transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease;
    }

    .paper-card:hover {
        transform: translateY(-4px);
        box-shadow: 0 16px 32px rgba(15, 23, 42, .10);
        border-color: rgba(14, 165, 233, .40);
    }

    .paper-card-header {
        display: flex;
        align-items: flex-start;
        justify-content: space-between;
        gap: 10px;
    }

    .paper-title {
        margin: 0;
        flex: 1;
        min-width: 0;
        font-size: 16px;
        font-weight: 700;
        color: var(--tech-text);
        line-height: 1.5;
        word-break: break-all;
        display: -webkit-box;
        -webkit-box-orient: vertical;
        -webkit-line-clamp: 2;
        overflow: hidden;
    }

    .level-badge {
        flex-shrink: 0;
        white-space: nowrap;
        font-size: 12px;
        font-weight: 500;
    }

    .level-vip {
        padding: 4px 12px;
        color: #0369a1;
        background: rgba(14, 165, 233, .10);
        border: 1px solid rgba(14, 165, 233, .35);
        border-radius: 999px;
    }

    .paper-tags {
        display: flex;
        flex-wrap: wrap;
        gap: 6px;
        min-height: 24px;
    }

    .paper-meta {
        display: flex;
        align-items: center;
        flex-wrap: wrap;
        gap: 8px;
        font-size: 13px;
        color: var(--tech-text-2);
    }

    .paper-meta span+span::before {
        content: '|';
        margin-right: 8px;
        color: #cbd5e1;
    }

    .price-line {
        font-size: 16px;
        font-weight: 700;
    }

    .price-paid {
        color: #f56c6c;
    }

    .price-member {
        color: var(--tech-accent-strong);
    }

    .price-free {
        color: #67c23a;
    }

    .access-tip {
        font-size: 12px;
        color: var(--tech-text-2);
    }

    .paper-footer {
        margin-top: auto;
        display: flex;
        gap: 10px;
    }

    .paper-footer .btn-secondary,
    .paper-footer .btn-primary {
        flex: 1;
        padding: 10px 8px;
        font-size: 14px;
        font-weight: 600;
        border-radius: 10px;
    }

    .btn-primary,
    .btn-secondary {
        display: inline-flex;
        align-items: center;
        justify-content: center;
        cursor: pointer;
        font-family: inherit;
        transition: transform .2s ease, box-shadow .2s ease, color .2s ease, background .2s ease;
    }

    .btn-primary {
        color: #ffffff;
        background: linear-gradient(135deg, var(--tech-accent) 0%, var(--tech-accent-2) 100%);
        border: none;
        border-radius: 12px;
        box-shadow: 0 8px 18px rgba(14, 165, 233, .28);
    }

    .btn-primary:hover:not(:disabled) {
        transform: translateY(-2px);
        box-shadow: 0 12px 24px rgba(14, 165, 233, .34);
    }

    .btn-primary:disabled {
        opacity: .6;
        cursor: not-allowed;
        box-shadow: none;
        transform: none;
    }

    .btn-secondary {
        color: var(--tech-text-2);
        background: #fff;
        border: 1px solid var(--tech-line);
        border-radius: 12px;
    }

    .btn-secondary:hover:not(:disabled) {
        color: var(--tech-text);
        background: var(--tech-panel-2);
    }

    .btn-secondary:disabled {
        opacity: .6;
        cursor: not-allowed;
    }

    .paper-empty {
        padding: 60px 0;
        text-align: center;
        font-size: 14px;
        color: var(--tech-text-2);
        background: var(--tech-panel);
        border: 1px solid var(--tech-line);
        border-radius: 16px;
        box-shadow: 0 12px 32px rgba(15, 23, 42, .08);
    }

    .paper-pagination {
        margin-top: 28px;
        display: flex;
        justify-content: center;
    }

    /* ===== 开始答题确认弹窗（自定义科技风 modal） ===== */
    .confirm-mask {
        position: fixed;
        inset: 0;
        z-index: 2000;
        display: flex;
        align-items: center;
        justify-content: center;
        padding: 24px;
        background: rgba(15, 23, 42, .55);
        -webkit-backdrop-filter: blur(3px);
        backdrop-filter: blur(3px);
        overflow-y: auto;
    }

    .confirm-card {
        position: relative;
        width: 100%;
        max-width: 460px;
        margin: auto;
        background: var(--tech-panel);
        border-radius: 18px;
        box-shadow: 0 24px 60px rgba(15, 23, 42, .30);
        overflow: hidden;
        padding: 26px 24px 24px;
    }

    .confirm-card::before {
        content: "";
        position: absolute;
        top: 0;
        left: 0;
        right: 0;
        height: 4px;
        background: linear-gradient(90deg, var(--tech-accent) 0%, var(--tech-accent-2) 100%);
    }

    .confirm-title {
        font-size: 19px;
        font-weight: 700;
        color: var(--tech-text);
        text-align: center;
    }

    .confirm-paper-title {
        margin-top: 14px;
        padding: 12px 14px;
        font-size: 14px;
        font-weight: 600;
        color: var(--tech-text);
        background: var(--tech-panel-2);
        border: 1px solid var(--tech-line);
        border-radius: 10px;
        word-break: break-all;
    }

    .confirm-summary {
        margin-top: 14px;
        display: grid;
        grid-template-columns: repeat(2, minmax(0, 1fr));
        gap: 10px;
    }

    .confirm-summary-item {
        padding: 10px 12px;
        background: var(--tech-panel-2);
        border: 1px solid var(--tech-line);
        border-radius: 10px;
    }

    .confirm-summary-item .label {
        display: block;
        font-size: 12px;
        color: var(--tech-text-2);
        margin-bottom: 4px;
    }

    .confirm-summary-item .value {
        font-size: 14px;
        font-weight: 600;
        color: var(--tech-text);
    }

    .confirm-footer {
        margin-top: 20px;
        display: flex;
        gap: 12px;
    }

    .confirm-footer .btn-secondary,
    .confirm-footer .btn-primary {
        flex: 1;
        padding: 12px 18px;
        font-size: 15px;
        font-weight: 600;
        border-radius: 11px;
    }

    .spinner {
        display: inline-block;
        width: 14px;
        height: 14px;
        margin-right: 6px;
        vertical-align: middle;
        border: 2px solid rgba(255, 255, 255, .35);
        border-top-color: #fff;
        border-radius: 50%;
        animation: sq-spin .7s linear infinite;
    }

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

    .confirm-fade-enter-active,
    .confirm-fade-leave-active {
        transition: opacity .22s ease;
    }

    .confirm-fade-enter-from,
    .confirm-fade-leave-to {
        opacity: 0;
    }

    .confirm-fade-enter-active .confirm-card,
    .confirm-fade-leave-active .confirm-card {
        transition: transform .24s ease;
    }

    .confirm-fade-enter-from .confirm-card,
    .confirm-fade-leave-to .confirm-card {
        transform: translateY(14px) scale(.97);
    }

    /* ===== 402 付费墙弹窗（复用 show-pjax 结构） ===== */
    .paywall-mask {
        position: fixed;
        inset: 0;
        z-index: 2000;
        display: flex;
        align-items: center;
        justify-content: center;
        padding: 24px;
        background: rgba(15, 23, 42, .55);
        -webkit-backdrop-filter: blur(3px);
        backdrop-filter: blur(3px);
        overflow-y: auto;
    }

    .paywall-card {
        position: relative;
        width: 100%;
        max-width: 480px;
        margin: auto;
        background: var(--tech-panel);
        border-radius: 18px;
        box-shadow: 0 24px 60px rgba(15, 23, 42, .30);
        overflow: hidden;
    }

    .paywall-card::before {
        content: "";
        position: absolute;
        top: 0;
        left: 0;
        right: 0;
        height: 4px;
        background: linear-gradient(90deg, var(--tech-accent) 0%, var(--tech-accent-2) 100%);
    }

    .paywall-header {
        padding: 26px 24px 0;
        text-align: center;
    }

    .paywall-icon {
        width: 54px;
        height: 54px;
        margin: 0 auto 12px;
        display: flex;
        align-items: center;
        justify-content: center;
        font-size: 26px;
        border-radius: 50%;
        background: linear-gradient(135deg, rgba(14, 165, 233, .16), rgba(99, 102, 241, .16));
        border: 1px solid rgba(14, 165, 233, .28);
    }

    .paywall-title {
        font-size: 19px;
        font-weight: 700;
        color: var(--tech-text);
        line-height: 1.5;
    }

    .paywall-desc {
        padding: 10px 24px 0;
        text-align: center;
        font-size: 13.5px;
        color: var(--tech-text-2);
        line-height: 1.7;
    }

    .paywall-packs {
        margin: 16px 24px 0;
    }

    .paywall-packs-title {
        font-size: 13.5px;
        font-weight: 600;
        color: var(--tech-text);
        margin-bottom: 10px;
        padding-left: 9px;
        border-left: 3px solid var(--tech-accent);
        line-height: 1.2;
    }

    .paywall-pack {
        display: flex;
        align-items: center;
        gap: 12px;
        padding: 12px 14px;
        background: #ffffff;
        border: 1px solid var(--tech-line);
        border-radius: 12px;
        transition: border-color .2s ease, box-shadow .2s ease;
    }

    .paywall-pack+.paywall-pack {
        margin-top: 10px;
    }

    .paywall-pack:hover {
        border-color: rgba(14, 165, 233, .45);
        box-shadow: 0 6px 16px rgba(15, 23, 42, .06);
    }

    .paywall-pack-main {
        flex: 1;
        min-width: 0;
    }

    .paywall-pack-name {
        font-size: 14px;
        font-weight: 600;
        color: var(--tech-text);
        margin-bottom: 4px;
        overflow: hidden;
        text-overflow: ellipsis;
        white-space: nowrap;
    }

    .paywall-pack-meta {
        display: flex;
        flex-wrap: wrap;
        gap: 6px 14px;
        font-size: 12px;
        color: var(--tech-text-2);
    }

    .paywall-pack-side {
        flex-shrink: 0;
        text-align: right;
    }

    .paywall-pack-price {
        display: flex;
        align-items: baseline;
        justify-content: flex-end;
        gap: 6px;
        margin-bottom: 6px;
    }

    .paywall-pack-price .now {
        font-size: 16px;
        font-weight: 700;
        color: var(--tech-accent-strong);
        font-variant-numeric: tabular-nums;
    }

    .paywall-pack-price .was {
        font-size: 12px;
        color: #94a3b8;
        text-decoration: line-through;
    }

    .paywall-pack-btn {
        padding: 6px 14px;
        font-size: 12.5px;
        font-weight: 600;
        color: var(--tech-accent-strong);
        background: rgba(14, 165, 233, .10);
        border: 1px solid rgba(14, 165, 233, .40);
        border-radius: 8px;
        cursor: pointer;
        transition: background .2s ease, color .2s ease, border-color .2s ease;
    }

    .paywall-pack-btn:hover {
        color: #ffffff;
        background: linear-gradient(135deg, var(--tech-accent) 0%, var(--tech-accent-2) 100%);
        border-color: transparent;
    }

    .paywall-footer {
        display: flex;
        gap: 12px;
        padding: 20px 24px 24px;
    }

    .paywall-btn {
        flex: 1;
        padding: 12px 18px;
        font-size: 15px;
        font-weight: 600;
        border-radius: 11px;
        cursor: pointer;
        transition: transform .2s ease, box-shadow .2s ease, background .2s ease;
    }

    .paywall-btn.secondary {
        color: var(--tech-text-2);
        background: #ffffff;
        border: 1px solid var(--tech-line);
    }

    .paywall-btn.secondary:hover {
        color: var(--tech-text);
        background: var(--tech-panel-2);
    }

    .paywall-btn.primary {
        color: #ffffff;
        background: linear-gradient(135deg, var(--tech-accent) 0%, var(--tech-accent-2) 100%);
        border: none;
        box-shadow: 0 8px 18px rgba(14, 165, 233, .28);
    }

    .paywall-btn.primary:hover {
        transform: translateY(-2px);
        box-shadow: 0 12px 24px rgba(14, 165, 233, .34);
    }

    .paywall-fade-enter-active,
    .paywall-fade-leave-active {
        transition: opacity .22s ease;
    }

    .paywall-fade-enter-from,
    .paywall-fade-leave-to {
        opacity: 0;
    }

    .paywall-fade-enter-active .paywall-card,
    .paywall-fade-leave-active .paywall-card {
        transition: transform .24s ease;
    }

    .paywall-fade-enter-from .paywall-card,
    .paywall-fade-leave-to .paywall-card {
        transform: translateY(14px) scale(.97);
    }

    /* ===== 自适应 ===== */
    @media (max-width: 1024px) {
        .paper-grid {
            grid-template-columns: repeat(2, 1fr);
        }
    }

    @media (max-width: 640px) {
        .sq-app {
            padding: 20px 12px 40px;
        }

        .sq-title {
            font-size: 21px;
        }

        .filter-panel {
            padding: 14px 12px;
        }

        .paper-card {
            padding: 16px;
        }

        .confirm-mask,
        .paywall-mask {
            padding: 14px;
        }

        .confirm-card,
        .paywall-card {
            max-width: 100%;
            border-radius: 16px;
        }

        .confirm-card {
            padding: 22px 18px 18px;
        }

        .confirm-summary {
            grid-template-columns: 1fr;
        }

        .paywall-header {
            padding: 22px 18px 0;
        }

        .paywall-desc {
            padding: 10px 18px 0;
        }

        .paywall-packs {
            margin-left: 18px;
            margin-right: 18px;
        }

        .paywall-pack {
            flex-direction: column;
            align-items: stretch;
        }

        .paywall-pack-side {
            text-align: left;
        }

        .paywall-pack-price {
            justify-content: flex-start;
        }

        .paywall-pack-btn {
            width: 100%;
        }

        .paywall-footer {
            flex-direction: column;
            padding: 18px 18px 20px;
        }

        .paywall-btn {
            width: 100%;
        }
    }