.sf-qbank {
    --sf-blue: #255884;
    --sf-blue-dark: #1d4568;
    --sf-green: #93C63D;
    --sf-green-dark: #79A72F;
    --sf-heading: #1f1f1f;
    --sf-text: #5f6368;
    --sf-muted: #7b858d;
    --sf-border: #dfe6ea;
    --sf-soft: #f5f8fa;
    --sf-free: #eef7df;

    width: min(1260px, calc(100% - 32px));
    margin: 0 auto;
    padding: 36px 0 60px;
}

.sf-qbank *,
.sf-qbank *::before,
.sf-qbank *::after {
    box-sizing: border-box;
}

.sf-qbank__hero {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    gap: 28px;
    padding: 30px;
    margin-bottom: 22px;
    border: 1px solid var(--sf-border);
    border-radius: 18px;
    background: linear-gradient(135deg, #fff, #f1f6fa);
}

.sf-qbank__eyebrow {
    display: block;
    margin-bottom: 7px;
    color: var(--sf-blue);
    font-size: 11px;
    font-weight: 800;
    letter-spacing: .08em;
    text-transform: uppercase;
}

.sf-qbank__hero h1 {
    margin: 0 0 8px;
    color: var(--sf-heading);
    font-size: clamp(30px, 4vw, 44px);
    line-height: 1.12;
}

.sf-qbank__hero p {
    max-width: 720px;
    margin: 0;
    color: var(--sf-text);
    line-height: 1.65;
}

.sf-qbank__summary {
    display: grid;
    grid-template-columns: repeat(3, minmax(82px, 1fr));
    gap: 8px;
    min-width: 300px;
}

.sf-qbank__summary span {
    padding: 12px 10px;
    border: 1px solid var(--sf-border);
    border-radius: 10px;
    background: #fff;
    color: var(--sf-muted);
    text-align: center;
    font-size: 11px;
}

.sf-qbank__summary strong {
    display: block;
    margin-bottom: 2px;
    color: var(--sf-heading);
    font-size: 19px;
}

.sf-qbank__layout {
    display: grid;
    grid-template-columns: 285px minmax(0, 1fr);
    gap: 22px;
    align-items: start;
}

.sf-qbank__sidebar,
.sf-qbank__practice {
    border: 1px solid var(--sf-border);
    border-radius: 16px;
    background: #fff;
    box-shadow: 0 8px 25px rgba(15, 23, 42, .05);
}

.sf-qbank__sidebar {
    position: sticky;
    top: 24px;
    padding: 18px;
}

.sf-qbank__sidebar-head {
    display: flex;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 14px;
}

.sf-qbank__sidebar-head span {
    color: var(--sf-muted);
    font-size: 12px;
}

.sf-qbank__question-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 7px;
    max-height: 390px;
    overflow-y: auto;
    padding-right: 4px;
}

.sf-qbank__question-number {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 0;
    height: 39px;
    border: 1px solid var(--sf-border);
    border-radius: 8px;
    background: #fff;
    color: var(--sf-heading);
    text-decoration: none !important;
    font-size: 12px;
    font-weight: 800;
}

.sf-qbank__question-number.is-free {
    background: var(--sf-free);
}

.sf-qbank__question-number.is-active {
    border-color: var(--sf-blue);
    background: var(--sf-blue);
    color: #fff;
}

.sf-qbank__question-number.is-locked {
    background: #f4f5f6;
    color: #9aa1a7;
    cursor: not-allowed;
}

.sf-qbank__question-number small {
    position: absolute;
    right: 2px;
    bottom: 1px;
    font-size: 8px;
}

.sf-qbank__upgrade-box {
    margin-top: 18px;
    padding: 15px;
    border-radius: 11px;
    background: #f2f7ea;
}

.sf-qbank__upgrade-box strong {
    color: var(--sf-heading);
    font-size: 13px;
}

.sf-qbank__upgrade-box p {
    margin: 5px 0 11px;
    color: var(--sf-text);
    font-size: 11px;
    line-height: 1.5;
}

.sf-qbank__upgrade-box a,
.sf-qbank__locked-panel a {
    display: inline-flex;
    justify-content: center;
    align-items: center;
    min-height: 40px;
    padding: 9px 14px;
    border-radius: 8px;
    background: var(--sf-green);
    color: #fff !important;
    text-decoration: none !important;
    font-size: 12px;
    font-weight: 800;
}

.sf-qbank__practice {
    min-height: 540px;
    padding: 28px;
}

.sf-qbank-question__topline {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding-bottom: 18px;
    margin-bottom: 22px;
    border-bottom: 1px solid var(--sf-border);
    color: var(--sf-muted);
    font-size: 12px;
    font-weight: 700;
}

.sf-qbank-question__free,
.sf-qbank-question__premium {
    padding: 6px 9px;
    border-radius: 999px;
    background: var(--sf-free);
    color: var(--sf-green-dark);
    font-size: 10px;
    font-weight: 800;
}

.sf-qbank-question__premium {
    background: #edf4f9;
    color: var(--sf-blue);
}

.sf-qbank-question__content {
    margin-bottom: 24px;
    color: var(--sf-heading);
    font-size: 17px;
    line-height: 1.65;
}

.sf-qbank-question__options {
    display: grid;
    gap: 11px;
}

.sf-qbank-option {
    display: grid;
    grid-template-columns: 22px 38px minmax(0, 1fr);
    align-items: center;
    gap: 10px;
    padding: 14px;
    border: 1px solid var(--sf-border);
    border-radius: 11px;
    cursor: pointer;
    transition: border-color .15s ease, background .15s ease;
}

.sf-qbank-option:hover {
    border-color: #bccbd5;
    background: #fafcfd;
}

.sf-qbank-option input {
    width: 17px;
    height: 17px;
}

.sf-qbank-option__key {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 34px;
    height: 34px;
    border-radius: 50%;
    background: #edf4f9;
    color: var(--sf-blue);
    font-weight: 800;
}

.sf-qbank-option__text {
    color: var(--sf-heading);
    line-height: 1.55;
}

.sf-qbank-question__check {
    min-width: 155px;
    min-height: 46px;
    margin-top: 18px;
    padding: 10px 18px;
    border: 0;
    border-radius: 9px;
    background: var(--sf-blue);
    color: #fff;
    font: inherit;
    font-size: 13px;
    font-weight: 800;
    cursor: pointer;
}

.sf-qbank-question__check:disabled {
    opacity: .6;
    cursor: wait;
}

.sf-qbank-question__feedback {
    margin-top: 18px;
    padding: 17px;
    border: 1px solid var(--sf-border);
    border-radius: 11px;
    background: var(--sf-soft);
    line-height: 1.55;
}

.sf-qbank-question__feedback[hidden] {
    display: none !important;
}

.sf-qbank-question__feedback.is-correct {
    border-color: #b8d88a;
    background: #f3f9e9;
}

.sf-qbank-question__feedback.is-incorrect,
.sf-qbank-question__feedback.is-error {
    border-color: #efc0c0;
    background: #fff5f5;
}

.sf-qbank-question__feedback > strong {
    display: block;
    margin-bottom: 7px;
    font-size: 15px;
}

.sf-qbank-question__rationale {
    margin-top: 12px;
    padding-top: 12px;
    border-top: 1px solid rgba(0,0,0,.08);
}

.sf-qbank-question__rationale b {
    display: block;
    margin-bottom: 4px;
}

.sf-qbank-question__nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid var(--sf-border);
}

.sf-qbank-question__nav a {
    color: var(--sf-blue);
    text-decoration: none;
    font-size: 13px;
    font-weight: 800;
}

.sf-qbank-question__nav a.is-upgrade {
    color: var(--sf-green-dark);
}

.sf-qbank__locked-panel {
    display: flex;
    min-height: 450px;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    max-width: 580px;
    margin: 0 auto;
    text-align: center;
}

.sf-qbank__lock-icon {
    font-size: 42px;
}

.sf-qbank__locked-panel h2 {
    margin: 12px 0 7px;
    font-size: 29px;
}

.sf-qbank__locked-panel p {
    margin: 0 0 18px;
    color: var(--sf-text);
    line-height: 1.6;
}

.sf-qbank-empty {
    padding: 30px;
    border: 1px solid #dfe6ea;
    border-radius: 12px;
    background: #f5f8fa;
    text-align: center;
}

@media (max-width: 900px) {
    .sf-qbank__hero {
        align-items: flex-start;
        flex-direction: column;
    }

    .sf-qbank__summary {
        width: 100%;
        min-width: 0;
    }

    .sf-qbank__layout {
        grid-template-columns: 1fr;
    }

    .sf-qbank__sidebar {
        position: static;
    }

    .sf-qbank__question-grid {
        grid-template-columns: repeat(10, minmax(38px, 1fr));
        max-height: 180px;
    }
}

@media (max-width: 620px) {
    .sf-qbank {
        width: min(100% - 20px, 1260px);
        padding: 22px 0 40px;
    }

    .sf-qbank__hero,
    .sf-qbank__practice {
        padding: 20px 16px;
    }

    .sf-qbank__summary {
        grid-template-columns: repeat(3, 1fr);
    }

    .sf-qbank__question-grid {
        grid-template-columns: repeat(5, 1fr);
    }

    .sf-qbank-question__content {
        font-size: 15px;
    }

    .sf-qbank-option {
        grid-template-columns: 20px 34px minmax(0, 1fr);
        padding: 12px 10px;
    }
}

/* =========================================================
   VISUAL EXPLANATION IMAGE
   ========================================================= */
.sf-qbank-question__explanation-image {
    margin-top: 16px;
    padding-top: 4px;
}

.sf-qbank-question__explanation-image img {
    display: block;
    width: auto;
    max-width: 100%;
    max-height: 620px;
    margin: 0;
    border: 1px solid var(--sf-border);
    border-radius: 12px;
    background: #fff;
    box-shadow: 0 8px 22px rgba(15, 23, 42, .07);
    object-fit: contain;
}