:root {
    /* Фон и панели */
    --qc-bg-deep: #0d1620;
    --qc-bg-shallow: #1a2836;
    --qc-panel: #1c2836;
    --qc-panel-hi: #243447;
    --qc-panel-line: rgba(120, 160, 200, 0.14);
    --qc-panel-line-hi: rgba(120, 160, 200, 0.32);

    /* Текст */
    --qc-text: #e8eef6;
    --qc-text-muted: #8ba0b5;
    --qc-text-faint: #5a6f84;

    /* Акценты по теории цвета */
    --qc-blue: #60a5fa;
    --qc-blue-soft: rgba(96, 165, 250, 0.15);
    --qc-blue-border: rgba(96, 165, 250, 0.4);

    --qc-purple: #c084fc;
    --qc-purple-soft: rgba(192, 132, 252, 0.15);
    --qc-purple-border: rgba(192, 132, 252, 0.4);

    --qc-green: #22c55e;
    --qc-green-light: #4ade80;
    --qc-green-soft: rgba(34, 197, 94, 0.15);
    --qc-green-border: rgba(34, 197, 94, 0.45);

    /* Тени */
    --qc-shadow-card: 0 1px 2px rgba(0, 0, 0, 0.25), 0 4px 14px rgba(0, 0, 0, 0.3);
    --qc-shadow-card-hover: 0 4px 8px rgba(0, 0, 0, 0.35), 0 12px 32px rgba(0, 0, 0, 0.5);
}

body.qc-page {
    background: var(--qc-bg-deep);
    background-image: linear-gradient(180deg, var(--qc-bg-shallow) 0%, var(--qc-bg-deep) 100%);
    background-repeat: no-repeat;
    background-size: 100% 100%;
    background-attachment: fixed;
    color: var(--qc-text);
    -webkit-font-smoothing: antialiased;
}

.qc-shell {
    width: 100%;
    max-width: 1180px;
    margin: 0 auto;
    padding: 24px 24px 40px;
    box-sizing: border-box;
}

/* ============================================================
   HERO
   ============================================================ */
.qc-hero {
    position: relative;
    margin: 12px 0 26px;
    padding: 0;
}

.qc-hero__title {
    margin: 0 0 20px;
    font-size: clamp(2.2rem, 4.2vw, 3.2rem);
    font-weight: 800;
    letter-spacing: -0.024em;
    line-height: 1.1;
    color: var(--qc-text);
    max-width: 860px;
}

.qc-hero__title em {
    font-style: normal;
    background: linear-gradient(90deg, #4ade80 0%, #22c55e 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
}

.qc-hero__lead {
    margin: 0 0 22px;
    font-size: clamp(1.1rem, 1.6vw, 1.3rem);
    line-height: 1.6;
    color: #c5d3e0;
    max-width: 780px;
}

.qc-hero__row {
    display: flex;
    gap: 18px;
    margin: 28px 0 24px;
    flex-wrap: wrap;
}

.qc-hero__fact {
    display: flex;
    flex-direction: column;
    gap: 2px;
    padding-left: 14px;
    border-left: 2px solid var(--qc-blue-border);
}

.qc-hero__fact:nth-child(2) {
    border-left-color: var(--qc-purple-border);
}

.qc-hero__fact-value {
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--qc-text);
    letter-spacing: -0.01em;
    line-height: 1.1;
}

.qc-hero__fact-label {
    font-size: 0.85rem;
    color: var(--qc-text-faint);
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.qc-hero__text {
    margin: 0 0 16px;
    font-size: clamp(1rem, 1.25vw, 1.08rem);
    line-height: 1.75;
    color: var(--qc-text-muted);
    max-width: 820px;
}

.qc-hero__text b {
    color: var(--qc-text);
    font-weight: 600;
}

.qc-hero__text--below {
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid var(--qc-panel-line);
    font-size: clamp(0.95rem, 1.1vw, 1rem);
    color: var(--qc-text-muted);
}

/* ============================================================
   FOLDER TITLE (non-root catalogs)
   ============================================================ */
.qc-folder-title {
    margin: 0;
    font-size: clamp(1.5rem, 2.8vw, 2rem);
    font-weight: 800;
    letter-spacing: -0.02em;
    line-height: 1.15;
    color: var(--qc-text);
}

.qc-folder-head {
    display: flex;
    align-items: center;
    gap: 14px;
    margin: 4px 0 22px;
    flex-wrap: wrap;
}

.qc-back {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    align-self: flex-start;
    padding: 8px 14px 8px 10px;
    background: var(--qc-panel);
    border: 1px solid var(--qc-panel-line);
    border-radius: 10px;
    color: var(--qc-text-muted);
    text-decoration: none;
    font-size: 0.88rem;
    font-weight: 500;
    transition: color 0.18s ease, border-color 0.18s ease, background 0.18s ease, transform 0.1s ease;
}

.qc-back:hover {
    color: var(--qc-green-light);
    border-color: var(--qc-green-border);
    background: var(--qc-panel-hi);
}

.qc-back:active {
    transform: scale(0.98);
}

.qc-back:focus-visible {
    outline: 2px solid var(--qc-green);
    outline-offset: 3px;
}

.qc-back svg {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
    display: block;
    transition: transform 0.18s ease;
}

.qc-back:hover svg {
    transform: translateX(-2px);
}

/* ============================================================
   HERO ACTIONS + JOIN BY KEY
   ============================================================ */
.qc-hero__actions {
    margin-top: 28px;
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    align-items: flex-start;
}

.qc-hero__qr {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    height: 48px;
    padding: 0 24px;
    box-sizing: border-box;
    gap: 10px;
    border: 1.5px solid var(--qc-green-border);
    border-radius: 12px;
    background: linear-gradient(135deg, rgba(34, 197, 94, 0.22), rgba(74, 222, 128, 0.14));
    color: #e6ffe9;
    font-family: inherit;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: border-color 0.18s ease, transform 0.1s ease, filter 0.18s ease, box-shadow 0.22s ease;
    box-shadow: 0 6px 18px rgba(34, 197, 94, 0.18);
}

.qc-hero__qr:hover {
    border-color: rgba(34, 197, 94, 0.9);
    filter: brightness(1.1);
    box-shadow: 0 8px 24px rgba(34, 197, 94, 0.3);
}

.qc-hero__qr:active {
    transform: scale(0.98);
}

.qc-hero__qr:focus-visible {
    outline: 2px solid var(--qc-green);
    outline-offset: 3px;
}

.qc-hero__qr svg {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
    display: block;
}

.qc-hero__or {
    align-self: flex-start;
    margin-top: 14px;
    color: var(--qc-text-faint);
    font-size: 0.95rem;
    user-select: none;
}

.qc-hero__join-wrap {
    display: flex;
    flex-direction: column;
    gap: 4px;
    width: 320px;
    max-width: 100%;
    min-width: 0;
}

.qc-hero__join-wrap .qrs-join {
    width: 100%;
    display: flex;
    gap: 8px;
    align-items: stretch;
}

.qc-hero__join-wrap .qrs-input {
    height: 48px;
    padding: 0 14px;
    box-sizing: border-box;
}

.qc-hero__join-wrap .qrs-key-mirror {
    padding: 0 14px;
}

.qc-hero__join-wrap .qrs-btn {
    height: 48px;
    padding: 0 22px;
    box-sizing: border-box;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.qc-hero__join-status {
    font-size: 0.82rem;
    line-height: 1.35;
    color: var(--qc-text-faint);
    min-height: 18px;
    padding: 0 2px;
}

.qc-hero__join-status.is-loading {
    color: var(--qc-text-muted);
}

.qc-hero__join-status.is-error {
    color: #f87171;
}

.qc-hero__hint {
    font-size: 0.9rem;
    color: var(--qc-text-faint);
    line-height: 1.4;
}

/* ============================================================
   BREADCRUMBS
   ============================================================ */
.qc-crumbs {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 6px;
    margin: 0 0 26px;
    padding: 10px 16px;
    background: var(--qc-panel);
    border: 1px solid var(--qc-panel-line);
    border-radius: 12px;
    font-size: 0.88rem;
}

.qc-crumb {
    color: var(--qc-text-muted);
    text-decoration: none;
    padding: 3px 8px;
    border-radius: 6px;
    cursor: pointer;
    transition: color 0.18s ease, background 0.18s ease;
}

.qc-crumb:hover {
    color: var(--qc-green-light);
    background: var(--qc-green-soft);
}

.qc-crumb--current {
    color: var(--qc-text);
    font-weight: 600;
    cursor: default;
}

.qc-crumb__sep {
    color: var(--qc-text-faint);
    user-select: none;
    padding: 0 2px;
}

/* ============================================================
   SEARCH
   ============================================================ */
.qc-search {
    margin: 0 0 22px;
}

.qc-search__field {
    position: relative;
    display: flex;
    align-items: center;
    width: 100%;
    max-width: 520px;
    background: var(--qc-panel);
    border: 1px solid var(--qc-panel-line);
    border-radius: 12px;
    transition: border-color 0.18s ease, background 0.18s ease;
}

.qc-search__field:focus-within {
    border-color: var(--qc-green-border);
    background: var(--qc-panel-hi);
}

.qc-search__icon {
    position: absolute;
    left: 14px;
    width: 18px;
    height: 18px;
    color: var(--qc-text-faint);
    pointer-events: none;
    transition: color 0.18s ease;
}

.qc-search__field:focus-within .qc-search__icon {
    color: var(--qc-green-light);
}

.qc-search__input {
    flex: 1 1 auto;
    width: 100%;
    padding: 12px 44px 12px 42px;
    background: transparent;
    border: none;
    outline: none;
    color: var(--qc-text);
    font-family: inherit;
    font-size: 0.95rem;
    line-height: 1.4;
}

.qc-search__input::placeholder {
    color: var(--qc-text-faint);
}

.qc-search__clear {
    position: absolute;
    right: 8px;
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
    background: transparent;
    border: none;
    border-radius: 8px;
    color: var(--qc-text-faint);
    font-size: 14px;
    line-height: 1;
    cursor: pointer;
    transition: background 0.18s ease, color 0.18s ease;
}

.qc-search__clear:hover {
    background: rgba(255, 255, 255, 0.06);
    color: var(--qc-text);
}

.qc-search__clear[hidden] {
    display: none;
}

/* ============================================================
   SEARCH RESULTS
   ============================================================ */
.qc-search-results {
    margin: 0 0 30px;
}

.qc-search-results[hidden] {
    display: none;
}

.qc-search-empty {
    padding: 26px 22px;
    background: var(--qc-panel);
    border: 1px dashed var(--qc-panel-line-hi);
    border-radius: 14px;
    color: var(--qc-text-muted);
    font-size: 0.95rem;
    line-height: 1.5;
    text-align: center;
}

.qc-search-empty[hidden] {
    display: none;
}

.qc-search-empty span {
    color: var(--qc-text);
    font-weight: 600;
}

@media (max-width: 640px) {
    .qc-search__field {
        max-width: 100%;
    }

    .qc-search__input {
        font-size: 16px;
        /* предотвращает зум на iOS */
    }
}

/* ============================================================
   MAIN / SECTIONS
   ============================================================ */
.qc-main {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.qc-main[hidden] {
    display: none;
}

.qc-section__title {
    margin: 0 0 14px;
    font-size: 1.15rem;
    font-weight: 700;
    letter-spacing: -0.01em;
    color: var(--qc-text);
}

.qc-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 16px;
}

/* ============================================================
   CARDS
   ============================================================ */
.qc-card {
    position: relative;
    display: flex;
    flex-direction: column;
    background: var(--qc-panel);
    border: 1px solid var(--qc-panel-line);
    border-radius: 16px;
    text-decoration: none;
    color: inherit;
    box-shadow: var(--qc-shadow-card);
    transition: transform 0.18s ease, box-shadow 0.22s ease, border-color 0.18s ease, background 0.18s ease;
    overflow: hidden;
    isolation: isolate;
}

.qc-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--qc-shadow-card-hover);
    border-color: var(--qc-green-border);
    background: var(--qc-panel-hi);
}

.qc-card--folder {
    flex-direction: row;
    align-items: center;
    gap: 14px;
    padding: 16px 18px;
    min-height: 84px;
}

.qc-card--folder:hover {
    border-color: var(--qc-green-border);
}

.qc-card--folder .qc-card__icon {
    flex: 0 0 auto;
    width: 48px;
    height: 48px;
    border-radius: 12px;
    background: var(--qc-green-soft);
    border: 1px solid var(--qc-green-border);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--qc-green-light);
    transition: background 0.2s ease, transform 0.2s ease;
}

.qc-card--folder:hover .qc-card__icon {
    background: rgba(34, 197, 94, 0.22);
    transform: scale(1.05);
}

.qc-card--folder .qc-card__icon svg {
    width: 24px;
    height: 24px;
    display: block;
}

.qc-card--folder .qc-card__body {
    flex: 1 1 auto;
    min-width: 0;
}

.qc-card--folder .qc-card__title {
    margin: 0 0 4px;
    font-size: 0.98rem;
    font-weight: 600;
    letter-spacing: -0.005em;
    color: var(--qc-text);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.qc-card--folder .qc-card__meta {
    font-size: 0.8rem;
    color: var(--qc-text-muted);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.qc-card__arrow {
    flex: 0 0 auto;
    font-size: 1.4rem;
    color: var(--qc-text-faint);
    line-height: 1;
    transition: transform 0.18s ease, color 0.18s ease;
}

.qc-card--folder:hover .qc-card__arrow {
    transform: translateX(3px);
    color: var(--qc-green-light);
}

.qc-card--test,
.qc-card--duel {
    padding: 0;
}

.qc-card__banner {
    position: relative;
    width: 100%;
    aspect-ratio: 16 / 9;
    overflow: hidden;
    background: linear-gradient(135deg, rgba(96, 165, 250, 0.28), rgba(59, 130, 246, 0.18));
    border-radius: 15px 15px 0 0;
}

.qc-card--duel .qc-card__banner {
    background: linear-gradient(135deg, rgba(192, 132, 252, 0.28), rgba(168, 85, 247, 0.18));
}

.qc-card__banner img {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.qc-card__banner[data-rotating]>img {
    opacity: 0;
    animation-timing-function: linear;
    animation-iteration-count: infinite;
}

@media (prefers-reduced-motion: reduce) {
    .qc-card__banner[data-rotating]>img {
        animation: none;
        opacity: 0;
    }

    .qc-card__banner[data-rotating]>img:first-child {
        opacity: 1;
    }
}

.qc-card--test .qc-card__body,
.qc-card--duel .qc-card__body {
    display: flex;
    flex-direction: column;
    gap: 10px;
    padding: 14px 18px 16px;
    flex: 1 1 auto;
}

.qc-card--test .qc-card__title,
.qc-card--duel .qc-card__title {
    margin: 0;
    font-size: 1rem;
    font-weight: 600;
    letter-spacing: -0.005em;
    color: var(--qc-text);
    line-height: 1.3;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.qc-card--test .qc-card__meta,
.qc-card--duel .qc-card__meta {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
    font-size: 0.8rem;
    color: var(--qc-text-muted);
    margin-top: auto;
}

.qc-card__count {
    color: var(--qc-text-faint);
}

.qc-card--test:hover {
    border-color: var(--qc-blue-border);
}

.qc-card--duel:hover {
    border-color: var(--qc-purple-border);
}

/* ============================================================
   BADGES
   ============================================================ */
.qc-badge {
    display: inline-flex;
    align-items: center;
    padding: 3px 10px;
    border-radius: 20px;
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 0.03em;
    text-transform: uppercase;
    border: 1px solid transparent;
}

.qc-badge--test {
    background: var(--qc-blue-soft);
    border-color: var(--qc-blue-border);
    color: var(--qc-blue);
}

.qc-badge--duel {
    background: var(--qc-purple-soft);
    border-color: var(--qc-purple-border);
    color: var(--qc-purple);
}

/* ============================================================
   EMPTY STATE
   ============================================================ */
.qc-empty {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 80px 24px;
    text-align: center;
    background: var(--qc-panel);
    border: 1px dashed var(--qc-panel-line-hi);
    border-radius: 18px;
    color: var(--qc-text-muted);
}

.qc-empty__icon {
    width: 64px;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--qc-text-faint);
    margin-bottom: 14px;
}

.qc-empty__icon svg {
    width: 48px;
    height: 48px;
}

.qc-empty__title {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--qc-text);
    margin-bottom: 6px;
}

.qc-empty__text {
    font-size: 0.88rem;
    max-width: 320px;
}

/* ============================================================
   LOAD MORE
   ============================================================ */
.qc-loadmore {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    padding: 30px 20px 10px;
}

.qc-loadmore__btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 28px;
    border: 1.5px solid var(--qc-green-border);
    border-radius: 12px;
    background: rgba(34, 197, 94, 0.14);
    color: var(--qc-green-light);
    font-family: inherit;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.18s ease, border-color 0.18s ease, transform 0.1s ease;
}

.qc-loadmore__btn:hover:not(:disabled) {
    background: rgba(34, 197, 94, 0.24);
    border-color: rgba(34, 197, 94, 0.8);
}

.qc-loadmore__btn:active:not(:disabled) {
    transform: scale(0.98);
}

.qc-loadmore__btn:disabled {
    opacity: 0.6;
    cursor: wait;
}

.qc-loadmore__hint {
    font-size: 0.82rem;
    color: var(--qc-text-muted);
    font-weight: 400;
}

.qc-loadmore__spinner {
    display: inline-flex;
    gap: 5px;
}

.qc-loadmore__spinner span {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--qc-green);
    animation: qcLoadPulse 1.2s ease-in-out infinite;
}

.qc-loadmore__spinner span:nth-child(2) {
    animation-delay: 0.15s;
}

.qc-loadmore__spinner span:nth-child(3) {
    animation-delay: 0.3s;
}

@keyframes qcLoadPulse {

    0%,
    100% {
        opacity: 0.4;
        transform: scale(0.85);
    }

    50% {
        opacity: 1;
        transform: scale(1.1);
    }
}

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 900px) {
    .qc-hero__row {
        gap: 14px;
    }

    .qc-hero__fact-value {
        font-size: 1.35rem;
    }
}

@media (max-width: 640px) {
    .qc-shell {
        padding: 18px 14px 32px;
    }

    .qc-hero {
        margin: 4px 0 22px;
    }

    .qc-hero__title {
        font-size: 1.7rem;
        margin-bottom: 16px;
    }

    .qc-hero__lead {
        font-size: 1rem;
    }

    .qc-hero__text {
        font-size: 0.94rem;
        line-height: 1.7;
    }

    .qc-hero__text--below {
        font-size: 0.9rem;
    }

    .qc-hero__row {
        margin: 22px 0 18px;
        gap: 16px;
    }

    .qc-hero__fact {
        padding-left: 12px;
    }

    .qc-hero__fact-value {
        font-size: 1.15rem;
    }

    .qc-hero__fact-label {
        font-size: 0.75rem;
    }

    .qc-hero__actions {
        flex-direction: column;
        align-items: stretch;
        gap: 16px;
    }

    .qc-hero__or {
        align-self: center;
        margin: 0;
    }

    .qc-hero__qr {
        width: 100%;
    }

    .qc-hero__join-wrap {
        width: 100%;
        max-width: none;
    }

    .qc-hero__join-wrap .qrs-join {
        flex-direction: row;
        gap: 8px;
    }

    .qc-hero__join-wrap .qrs-btn {
        width: auto;
        padding: 0 16px;
    }

    .qc-hero__join-wrap .qrs-input {
        font-size: 16px;
        padding: 0 12px;
    }

    .qc-hero__join-wrap .qrs-key-mirror {
        font-size: 16px;
        padding: 0 12px;
    }

    .qc-hero__hint {
        text-align: center;
    }

    .qc-grid {
        grid-template-columns: 1fr;
    }

    .qc-card {
        min-height: auto;
    }

    .qc-card--folder {
        padding: 14px 16px;
    }

    .qc-card--folder .qc-card__icon {
        width: 42px;
        height: 42px;
    }

    .qc-card--folder .qc-card__icon svg {
        width: 22px;
        height: 22px;
    }

    .qc-card--test .qc-card__body,
    .qc-card--duel .qc-card__body {
        padding: 12px 16px 14px;
    }

    .qc-loadmore__btn {
        width: 100%;
        justify-content: center;
    }
}

@media (prefers-reduced-motion: reduce) {

    .qc-card,
    .qc-card__arrow,
    .qc-card__icon,
    .qc-crumb,
    .qc-loadmore__btn,
    .qc-hero__qr {
        transition: none;
    }

    .qc-loadmore__spinner span {
        animation: none;
        opacity: 1;
    }
}