:root {
    --bg: #08090a;
    --bg-elev: #0f1113;
    --bg-card: #101214;
    --border: #1e2126;
    --border-hover: #33383f;
    --text: #f3f4f6;
    --text-dim: #9aa1ac;
    --text-faint: #5b626c;
    --accent: #ffffff;
    --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
    --matrix: "Doto", var(--mono);
    --sans: "Inter", system-ui, -apple-system, sans-serif;
    /* Soft difficulty palette (dark UI) */
    --diff-low-bg: rgba(234, 179, 8, 0.12);
    --diff-low-border: rgba(250, 204, 21, 0.32);
    --diff-low-text: #fde68a;
    --diff-medium-bg: rgba(249, 115, 22, 0.12);
    --diff-medium-border: rgba(251, 146, 60, 0.34);
    --diff-medium-text: #fdba74;
    --diff-hard-bg: rgba(244, 63, 94, 0.12);
    --diff-hard-border: rgba(251, 113, 133, 0.34);
    --diff-hard-text: #fda4af;
    --diff-expert-bg: rgba(168, 85, 247, 0.14);
    --diff-expert-border: rgba(192, 132, 252, 0.36);
    --diff-expert-text: #d8b4fe;
    --panel-shadow:
        0 0 0 1px rgba(255, 255, 255, 0.06),
        0 12px 32px rgba(110, 118, 132, 0.14),
        0 28px 56px rgba(90, 98, 112, 0.1);
    --panel-shadow-hover:
        0 0 0 1px rgba(255, 255, 255, 0.08),
        0 16px 40px rgba(110, 118, 132, 0.18),
        0 36px 72px rgba(90, 98, 112, 0.14);
}

* { box-sizing: border-box; }

html, body {
    margin: 0;
    padding: 0;
    background: var(--bg);
    color: var(--text);
    font-family: var(--sans);
    -webkit-font-smoothing: antialiased;
    line-height: 1.5;
}

a { color: inherit; text-decoration: none; }

.accent { color: var(--accent); }
.muted { color: var(--text-faint); }

/* ---------- header ---------- */
.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(8, 9, 10, 0.72);
    backdrop-filter: blur(16px) saturate(140%);
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
    box-shadow: 0 12px 40px rgba(80, 90, 105, 0.08);
}
.site-header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
    padding: 14px 32px;
}
.brand {
    display: flex;
    align-items: center;
    gap: 12px;
}
.brand-logo {
    height: 44px;
    width: auto;
    max-width: 180px;
    object-fit: contain;
    display: block;
}
.brand-name { font-weight: 700; letter-spacing: -0.02em; font-size: 18px; }
.header-profile {
    display: flex;
    align-items: center;
    gap: 10px;
}
.profile-avatar {
    width: 38px;
    height: 38px;
    border-radius: 11px;
    overflow: hidden;
    flex-shrink: 0;
    border: 1px solid rgba(255, 255, 255, 0.1);
}
.profile-avatar svg {
    width: 100%;
    height: 100%;
    display: block;
}
.profile-rank {
    font-family: var(--mono);
    font-size: 10px;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    padding: 6px 11px;
    border-radius: 999px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    background: rgba(255, 255, 255, 0.04);
    color: var(--text-dim);
    white-space: nowrap;
}
.profile-rank.rank-apprentice {
    color: #a5b4fc;
    border-color: rgba(129, 140, 248, 0.4);
    background: rgba(99, 102, 241, 0.14);
}
.profile-rank.rank-samurai {
    color: #fca5a5;
    border-color: rgba(251, 113, 133, 0.4);
    background: rgba(244, 63, 94, 0.14);
}
.profile-rank.rank-ninja {
    color: #d8b4fe;
    border-color: rgba(192, 132, 252, 0.4);
    background: rgba(168, 85, 247, 0.16);
}
.profile-rank.rank-master,
.profile-rank.rank-kensei {
    color: #fde68a;
    border-color: rgba(250, 204, 21, 0.4);
    background: rgba(234, 179, 8, 0.14);
}

.site-main { max-width: 1200px; margin: 0 auto; padding: 0 32px; }
.page-home .site-main,
.page-room .site-main {
    max-width: min(1760px, 96vw);
    padding: 0 clamp(20px, 3vw, 56px);
}
.page-home .site-header-inner,
.page-home .site-footer-inner,
.page-room .site-header-inner,
.page-room .site-footer-inner {
    max-width: min(1760px, 96vw);
    padding-left: clamp(20px, 3vw, 56px);
    padding-right: clamp(20px, 3vw, 56px);
}
.page-home .lab-grid {
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 22px;
}
.page-home .welcome-panel {
    padding: 48px 0 0;
    margin-bottom: 0;
    border-bottom: 1px solid var(--border);
}
.page-home .about { max-width: 820px; }
.page-home {
    min-height: 100vh;
    background-color: var(--bg);
    background-image:
        radial-gradient(ellipse 120% 80% at 10% -8%, rgba(255, 255, 255, 0.08), transparent 58%),
        radial-gradient(ellipse 90% 65% at 92% 12%, rgba(255, 255, 255, 0.045), transparent 52%),
        radial-gradient(ellipse 100% 70% at 50% 108%, rgba(255, 255, 255, 0.035), transparent 50%);
    background-attachment: fixed;
}

/* ---------- welcome panel ---------- */
.welcome-panel {
    padding: 40px 0 0;
}
.page-home .welcome-inner {
    display: flex;
    flex-direction: column;
    gap: 28px;
    padding-bottom: 36px;
}
.welcome-left {
    position: relative;
    min-width: 0;
    flex: 1 1 auto;
}
.welcome-greeting {
    font-family: var(--mono);
    font-size: 12px;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-faint);
    margin: 0 0 14px;
}
.welcome-quote {
    margin: 0 0 14px;
    padding: 0;
    border: none;
    font-size: clamp(22px, 3.2vw, 30px);
    line-height: 1.35;
    letter-spacing: -0.025em;
    font-weight: 600;
    color: var(--text);
}
.welcome-sub {
    margin: 0;
    font-size: 15px;
    line-height: 1.6;
    color: var(--text-dim);
    max-width: 58ch;
}
.welcome-dash {
    display: grid;
    gap: 1px;
    width: 100%;
    min-width: 0;
    border-radius: 16px;
    overflow: hidden;
    background: linear-gradient(145deg, rgba(255, 255, 255, 0.1), rgba(255, 255, 255, 0.03));
    padding: 1px;
    filter:
        drop-shadow(0 0 1px rgba(255, 255, 255, 0.06))
        drop-shadow(0 14px 32px rgba(115, 123, 138, 0.16))
        drop-shadow(0 32px 64px rgba(95, 103, 118, 0.12));
    transition: filter 0.25s ease;
}
.welcome-dash:hover {
    filter:
        drop-shadow(0 0 1px rgba(255, 255, 255, 0.08))
        drop-shadow(0 18px 40px rgba(115, 123, 138, 0.2))
        drop-shadow(0 40px 80px rgba(95, 103, 118, 0.15));
}
.dash-metrics {
    display: grid;
    grid-template-columns: minmax(156px, 1.2fr) 1fr minmax(92px, 0.8fr);
    gap: 1px;
    background: rgba(255, 255, 255, 0.06);
}
.dash-metric {
    display: flex;
    flex-direction: column;
    gap: 4px;
    padding: 18px 16px;
    background: rgba(12, 14, 18, 0.92);
    backdrop-filter: blur(14px);
}
.dash-metric-tasks {
    min-width: 156px;
}
.welcome-dash .dash-metric-value,
.welcome-dash .dash-resume-meta {
    font-family: var(--matrix);
    font-weight: 700;
    letter-spacing: 0.04em;
    font-variant-numeric: tabular-nums;
    white-space: nowrap;
}
.dash-metric-value {
    font-size: 28px;
    line-height: 1;
}
.welcome-dash .dash-metric-value {
    font-size: 26px;
}
.dash-metric-label {
    font-family: var(--mono);
    font-size: 10px;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--text-faint);
    margin-top: 4px;
}
.dash-metric-rank {
    align-items: flex-start;
}
.dash-rank-tag {
    font-family: var(--mono);
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    padding: 6px 10px;
    border-radius: 999px;
    border: 1px solid var(--border-hover);
    background: var(--bg-elev);
    color: var(--text-dim);
}
.dash-rank-tag.rank-apprentice {
    color: #a5b4fc;
    border-color: rgba(129, 140, 248, 0.35);
    background: rgba(99, 102, 241, 0.12);
}
.dash-rank-tag.rank-samurai {
    color: #fca5a5;
    border-color: rgba(251, 113, 133, 0.35);
    background: rgba(244, 63, 94, 0.12);
}
.dash-rank-tag.rank-ninja {
    color: #d8b4fe;
    border-color: rgba(192, 132, 252, 0.35);
    background: rgba(168, 85, 247, 0.14);
}
.dash-rank-tag.rank-master,
.dash-rank-tag.rank-kensei {
    color: #fde68a;
    border-color: rgba(250, 204, 21, 0.35);
    background: rgba(234, 179, 8, 0.12);
}
.dash-resume {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
    padding: 18px 20px;
    background:
        linear-gradient(120deg, rgba(255, 255, 255, 0.07), transparent 55%),
        rgba(12, 14, 18, 0.94);
    backdrop-filter: blur(14px);
    transition: background 0.2s ease, transform 0.2s ease;
}
.dash-resume:hover {
    background:
        linear-gradient(120deg, rgba(255, 255, 255, 0.11), transparent 55%),
        rgba(14, 16, 20, 0.96);
}
.dash-resume-copy {
    display: flex;
    flex-direction: column;
    gap: 6px;
    min-width: 0;
    flex: 1;
}
.dash-resume-kicker {
    font-family: var(--mono);
    font-size: 10px;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-faint);
}
.dash-resume-title {
    font-size: 16px;
    font-weight: 600;
    letter-spacing: -0.02em;
    color: var(--text);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}
.dash-resume-track {
    height: 4px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.08);
    overflow: hidden;
    margin-top: 2px;
}
.dash-resume-fill {
    display: block;
    height: 100%;
    border-radius: inherit;
    background: linear-gradient(90deg, rgba(255, 255, 255, 0.45), #fff);
    transition: width 0.45s ease;
}
.dash-resume-meta {
    font-family: var(--mono);
    font-size: 11px;
    color: var(--text-faint);
}
.dash-resume-go {
    flex-shrink: 0;
    width: 40px;
    height: 40px;
    display: grid;
    place-items: center;
    border-radius: 999px;
    border: 1px solid rgba(255, 255, 255, 0.12);
    background: rgba(255, 255, 255, 0.06);
    font-size: 18px;
    line-height: 1;
    transition: transform 0.2s ease, background 0.2s ease, border-color 0.2s ease;
}
.dash-resume:hover .dash-resume-go {
    transform: translateX(2px);
    background: rgba(255, 255, 255, 0.12);
    border-color: rgba(255, 255, 255, 0.22);
}
@media (max-width: 640px) {
    .dash-metrics {
        grid-template-columns: 1fr;
    }
    .dash-metric {
        flex-direction: row;
        flex-wrap: wrap;
        align-items: baseline;
        column-gap: 8px;
    }
    .dash-metric-label {
        width: 100%;
        margin-top: 0;
    }
}
.welcome-rank-card.rank-bump {
    animation: rank-panel-bump 0.65s ease;
}
@keyframes rank-panel-bump {
    0%, 100% {
        transform: scale(1);
        box-shadow: var(--panel-shadow);
    }
    35% {
        transform: scale(1.025);
        box-shadow:
            0 0 0 1px rgba(255, 255, 255, 0.08),
            0 16px 40px rgba(110, 118, 132, 0.18),
            0 36px 72px rgba(90, 98, 112, 0.14);
    }
}
.welcome-fill.rank-bump-fill {
    transition: width 0.85s cubic-bezier(0.22, 1, 0.36, 1);
}
.welcome-rank-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 22px 24px;
    box-shadow: var(--panel-shadow);
    transition: box-shadow 0.25s ease;
}
.welcome-rank-card:hover {
    box-shadow: var(--panel-shadow-hover);
}
.rank-head {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 10px;
    flex-wrap: wrap;
}
.rank-badge {
    font-family: var(--mono);
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    padding: 5px 10px;
    border-radius: 999px;
    border: 1px solid var(--border-hover);
    color: var(--text-dim);
    background: var(--bg-elev);
}
.rank-badge.rank-apprentice {
    color: #a5b4fc;
    border-color: rgba(129, 140, 248, 0.35);
    background: rgba(99, 102, 241, 0.1);
}
.rank-badge.rank-samurai {
    color: #fca5a5;
    border-color: rgba(251, 113, 133, 0.35);
    background: rgba(244, 63, 94, 0.1);
}
.rank-badge.rank-ninja {
    color: #d8b4fe;
    border-color: rgba(192, 132, 252, 0.35);
    background: rgba(168, 85, 247, 0.12);
}
.rank-badge.rank-master,
.rank-badge.rank-kensei {
    color: #fde68a;
    border-color: rgba(250, 204, 21, 0.35);
    background: rgba(234, 179, 8, 0.1);
}
.rank-title {
    margin: 0;
    font-size: 20px;
    font-weight: 600;
    letter-spacing: -0.02em;
}
.rank-desc {
    margin: 0 0 18px;
    font-size: 14px;
    line-height: 1.55;
    color: var(--text-dim);
    max-width: 62ch;
}
.welcome-progress-meta {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: 12px;
    flex-wrap: wrap;
    margin-bottom: 10px;
    font-size: 13px;
}
.welcome-progress-meta span:first-child {
    font-family: var(--mono);
    color: var(--text);
}
.rank-next {
    color: var(--text-faint);
    font-size: 12px;
}
.welcome-bar {
    height: 8px;
    border-radius: 999px;
    background: var(--bg-elev);
    overflow: hidden;
}
.welcome-fill {
    background: linear-gradient(90deg, rgba(255, 255, 255, 0.55), #fff);
    transition: width 0.45s ease;
}

@media (min-width: 768px) {
    .page-home .welcome-panel { padding-top: 48px; }
    .page-home .welcome-inner {
        flex-direction: row;
        align-items: flex-start;
        gap: clamp(32px, 4vw, 64px);
        padding-bottom: 40px;
    }
    .page-home .welcome-left,
    .page-home .welcome-dash {
        flex: 1 1 0;
        min-width: 0;
        width: 50%;
    }
}

@media (min-width: 960px) {
    .page-home .welcome-panel { padding-top: 56px; }
}

/* ---------- controls ---------- */
.controls {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
    padding: 24px 0;
    flex-wrap: wrap;
}
.filter-group { display: flex; gap: 8px; flex-wrap: wrap; }
.chip {
    font-family: var(--mono);
    font-size: 13px;
    color: var(--text-dim);
    background: transparent;
    border: 1px solid var(--border);
    padding: 7px 16px;
    border-radius: 999px;
    cursor: pointer;
    transition: all .15s;
}
.chip:hover { border-color: var(--border-hover); color: var(--text); }
.chip.active { background: var(--text); color: #000; border-color: var(--text); }
.chip[data-value="Low"].active {
    background: var(--diff-low-bg);
    color: var(--diff-low-text);
    border-color: var(--diff-low-border);
}
.chip[data-value="Medium"].active {
    background: var(--diff-medium-bg);
    color: var(--diff-medium-text);
    border-color: var(--diff-medium-border);
}
.chip[data-value="Hard"].active {
    background: var(--diff-hard-bg);
    color: var(--diff-hard-text);
    border-color: var(--diff-hard-border);
}
.chip[data-value="Expert"].active {
    background: var(--diff-expert-bg);
    color: var(--diff-expert-text);
    border-color: var(--diff-expert-border);
}
.room-card[data-difficulty="Low"] { box-shadow: inset 0 1px 0 var(--diff-low-border); }
.room-card[data-difficulty="Medium"] { box-shadow: inset 0 1px 0 var(--diff-medium-border); }
.room-card[data-difficulty="Hard"] { box-shadow: inset 0 1px 0 var(--diff-hard-border); }
.room-card[data-difficulty="Expert"] { box-shadow: inset 0 1px 0 var(--diff-expert-border); }
.search-box {
    flex: 1;
    min-width: 240px;
    max-width: 340px;
    background: var(--bg-elev);
    border: 1px solid var(--border);
    color: var(--text);
    font-family: var(--mono);
    font-size: 13px;
    padding: 10px 16px;
    border-radius: 8px;
    outline: none;
    transition: border-color .15s;
}
.search-box:focus { border-color: var(--border-hover); }
.search-box::placeholder { color: var(--text-faint); }

/* ---------- lab grid ---------- */
.lab-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 18px;
    padding-bottom: 72px;
}
.lab-card {
    display: flex;
    flex-direction: column;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 22px;
    transition: transform .18s ease, border-color .18s ease, background .18s ease;
    position: relative;
    overflow: hidden;
}
.lab-card::before {
    content: "";
    position: absolute;
    inset: 0;
    background: radial-gradient(600px circle at var(--x, 50%) var(--y, 0%), rgba(255,255,255,0.05), transparent 40%);
    opacity: 0;
    transition: opacity .2s;
    pointer-events: none;
}
.lab-card:hover { transform: translateY(-3px); border-color: var(--border-hover); background: #14171a; }
.lab-card:hover::before { opacity: 1; }
.lab-card-top { display: flex; align-items: center; justify-content: space-between; margin-bottom: 14px; }
.lab-category {
    font-family: var(--mono);
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.14em;
    color: var(--text-faint);
}
.badge {
    font-family: var(--mono);
    font-size: 11px;
    font-weight: 600;
    padding: 4px 10px;
    border-radius: 999px;
    border: 1px solid transparent;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    backdrop-filter: blur(6px);
}
.badge-low {
    color: var(--diff-low-text);
    background: var(--diff-low-bg);
    border-color: var(--diff-low-border);
}
.badge-medium {
    color: var(--diff-medium-text);
    background: var(--diff-medium-bg);
    border-color: var(--diff-medium-border);
}
.badge-hard {
    color: var(--diff-hard-text);
    background: var(--diff-hard-bg);
    border-color: var(--diff-hard-border);
}
.badge-expert {
    color: var(--diff-expert-text);
    background: var(--diff-expert-bg);
    border-color: var(--diff-expert-border);
}
.lab-title { font-size: 19px; font-weight: 600; letter-spacing: -0.01em; margin: 0 0 8px; }
.lab-desc { font-size: 14px; color: var(--text-dim); margin: 0 0 16px; flex: 1; }
.lab-tags { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 16px; }
.tag { font-family: var(--mono); font-size: 11px; color: var(--text-faint); }
.lab-cta {
    font-family: var(--mono);
    font-size: 13px;
    color: var(--text);
    display: flex;
    align-items: center;
    gap: 8px;
}
.lab-cta .arrow { transition: transform .18s; }
.lab-card:hover .lab-cta .arrow { transform: translateX(4px); }
.no-results { grid-column: 1 / -1; text-align: center; color: var(--text-faint); font-family: var(--mono); padding: 40px; }

/* ---------- about ---------- */
.about { padding: 40px 0 96px; border-top: 1px solid var(--border); max-width: 720px; }
.about h2 { font-size: 24px; letter-spacing: -0.02em; }
.about p { color: var(--text-dim); }

/* ---------- footer ---------- */
.site-footer {
    border-top: 1px solid var(--border);
}
.site-footer-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 16px 28px;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
    padding: 28px 32px;
    font-size: 13px;
    color: var(--text-dim);
}
.footer-copy {
    display: flex;
    flex-direction: column;
    gap: 4px;
}
.footer-social {
    display: flex;
    flex-wrap: wrap;
    gap: 8px 20px;
    font-family: var(--mono);
    font-size: 12px;
}
.footer-social a {
    color: var(--text-dim);
    transition: color .15s;
}
.footer-social a:hover { color: var(--text); }

/* ---------- lab pages (shared) ---------- */
.lab-shell { padding: 48px 0 96px; max-width: 860px; }
.room-shell { max-width: none; width: 100%; }
.room-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr);
    gap: 28px;
    align-items: start;
}
.room-aside {
    position: relative;
}
.room-dash {
    position: sticky;
    top: 88px;
}
.room-dash .dash-metrics {
    grid-template-columns: 1fr;
}
.room-dash .dash-metric {
    padding: 16px 18px;
}
.room-dash .dash-metric-value {
    font-size: 28px;
}
@media (min-width: 960px) {
    .room-layout {
        grid-template-columns: minmax(0, 1fr) minmax(280px, 340px);
    }
}
.lab-back { font-family: var(--mono); font-size: 13px; color: var(--text-dim); display: inline-block; margin-bottom: 24px; }
.lab-back:hover { color: var(--text); }
.lab-header { border-bottom: 1px solid var(--border); padding-bottom: 20px; margin-bottom: 28px; }
.lab-header h1 { font-size: 30px; letter-spacing: -0.02em; margin: 8px 0; }
.lab-panel {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 26px;
    margin-bottom: 20px;
}
.lab-panel h2, .lab-panel h3 { margin-top: 0; letter-spacing: -0.01em; }
.scenario-brief {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-left: 3px solid var(--accent, #6ee7b7);
    border-radius: 12px;
    padding: 20px 22px;
    margin: 18px 0 22px;
}
.scenario-brief h3, .scenario-brief h4 {
    margin: 0 0 10px;
    font-size: 13px;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--text-dim);
}
.scenario-brief h4 { margin-top: 16px; }
.scenario-brief p { margin: 0; line-height: 1.55; }
.approach-steps {
    margin: 0;
    padding-left: 1.25rem;
    line-height: 1.55;
}
.approach-steps li { margin-bottom: 6px; }
.approach-steps li:last-child { margin-bottom: 0; }
.task-scenario { margin-bottom: 16px; }
.lab-app-header {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 20px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border);
}
.lab-app-logo {
    font-weight: 700;
    font-size: 20px;
    letter-spacing: -0.02em;
}
.lab-steps {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 20px;
}
.lab-step {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 13px;
    color: var(--text-dim);
    background: var(--bg-elev);
    border: 1px solid var(--border);
    border-radius: 999px;
    padding: 6px 12px 6px 6px;
}
.lab-step span {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: var(--bg-card);
    border: 1px solid var(--border);
    font-family: var(--mono);
    font-size: 11px;
}
.lab-step.active {
    color: var(--text);
    border-color: var(--accent, #6ee7b7);
}
.lab-step.active span {
    background: var(--accent, #6ee7b7);
    color: #0a0c0f;
    border-color: transparent;
}
.lab-hint {
    font-family: var(--mono);
    font-size: 13px;
    color: var(--text-dim);
    background: var(--bg-elev);
    border: 1px solid var(--border);
    border-left: 3px solid var(--border-hover);
    border-radius: 8px;
    padding: 14px 16px;
    margin-bottom: 20px;
}
.lab-hint b { color: var(--text); }
label { display: block; font-size: 14px; color: var(--text-dim); margin-bottom: 8px; }
input[type=text], input[type=url], input[type=password], input[type=email], textarea, select {
    width: 100%;
    background: var(--bg-elev);
    border: 1px solid var(--border);
    color: var(--text);
    font-family: var(--mono);
    font-size: 14px;
    padding: 11px 14px;
    border-radius: 8px;
    outline: none;
    margin-bottom: 16px;
}
input:focus, textarea:focus, select:focus { border-color: var(--border-hover); }
textarea { min-height: 120px; resize: vertical; }
.btn {
    display: inline-block;
    background: var(--text);
    color: #000;
    font-family: var(--mono);
    font-weight: 600;
    font-size: 14px;
    border: 1px solid var(--text);
    padding: 11px 22px;
    border-radius: 8px;
    cursor: pointer;
    transition: opacity .15s;
}
.btn:hover { opacity: 0.85; }
.btn-ghost { background: transparent; color: var(--text); border-color: var(--border-hover); }
.output {
    background: #000;
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 16px;
    font-family: var(--mono);
    font-size: 13px;
    color: #d1d5db;
    white-space: pre-wrap;
    word-break: break-word;
    overflow-x: auto;
}
.alert { border-radius: 8px; padding: 12px 16px; margin-bottom: 16px; font-size: 14px; border: 1px solid var(--border-hover); }
.alert-error { background: #1a1113; border-color: #40282c; color: #f3d0d4; }
.alert-success { background: #101a12; border-color: #26402c; color: #d0f0d6; }
.alert-info { background: #0f1418; border-color: #263340; color: #d0e2f0; }
table { width: 100%; border-collapse: collapse; font-size: 14px; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--border); }
th { color: var(--text-faint); font-family: var(--mono); font-size: 12px; text-transform: uppercase; letter-spacing: 0.08em; }
.article { border-bottom: 1px solid var(--border); padding: 18px 0; }
.article h3 { margin: 0 0 6px; }
.article-meta { font-family: var(--mono); font-size: 12px; color: var(--text-faint); }
.link { color: var(--text); text-decoration: underline; text-underline-offset: 3px; }
.file-list { list-style: none; padding: 0; }
.file-list li { font-family: var(--mono); font-size: 13px; padding: 8px 0; border-bottom: 1px solid var(--border); }

.flash-wrap { padding-top: 20px; }
.bac-nav { display: flex; gap: 14px; flex-wrap: wrap; margin-bottom: 24px; font-family: var(--mono); font-size: 13px; }
.bac-nav a { color: var(--text-dim); }
.bac-nav a:hover { color: var(--text); }
.video-card { border: 1px solid var(--border); border-radius: 10px; padding: 16px; margin-bottom: 12px; }
.locked { text-align: center; padding: 40px; color: var(--text-faint); font-family: var(--mono); }

/* ---------- rooms / progress ---------- */
.room-meta { display: flex; gap: 10px; margin-bottom: 14px; }
.progress-wrap {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 14px;
    flex-wrap: wrap;
}
.progress-bar {
    flex: 1;
    min-width: 120px;
    height: 6px;
    background: var(--border);
    border-radius: 999px;
    overflow: hidden;
}
.progress-fill {
    display: block;
    height: 100%;
    width: 0;
    background: var(--text);
    border-radius: 999px;
    transition: width .25s ease;
}
.progress-label, .progress-points {
    font-family: var(--mono);
    font-size: 12px;
    color: var(--text-dim);
    white-space: nowrap;
}
.room-progress { margin: 20px 0 16px; }
.room-cleared {
    display: flex;
    align-items: flex-start;
    gap: 14px;
    margin-top: 18px;
    padding: 14px 16px;
    border-radius: 12px;
    border: 1px solid rgba(250, 204, 21, 0.35);
    background: rgba(234, 179, 8, 0.08);
}
.room-cleared-icon {
    flex-shrink: 0;
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 999px;
    background: rgba(250, 204, 21, 0.18);
    color: #fde68a;
    font-size: 14px;
    font-weight: 700;
}
.room-cleared-copy strong {
    display: block;
    font-size: 15px;
    letter-spacing: -0.01em;
    margin-bottom: 4px;
    color: #fde68a;
}
.room-cleared-copy p {
    margin: 0;
    font-size: 13px;
    line-height: 1.5;
    color: var(--text-dim);
}
.room-cleared.celebrate {
    animation: room-cleared-in 0.45s ease, room-cleared-flash 1.1s ease 0.15s;
}
@keyframes room-cleared-in {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}
@keyframes room-cleared-flash {
    0%, 100% { box-shadow: none; }
    50% { box-shadow: 0 0 0 1px rgba(250, 204, 21, 0.45), 0 0 28px rgba(234, 179, 8, 0.15); }
}
.room-shell.room-complete .lab-header {
    border-bottom-color: rgba(250, 204, 21, 0.2);
}
.btn-sm { padding: 8px 14px; font-size: 12px; }
.objectives { margin: 0; padding-left: 20px; color: var(--text-dim); }
.objectives li { margin-bottom: 6px; }

.tasks { display: flex; flex-direction: column; gap: 12px; padding-bottom: 64px; }
.task {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 14px;
    overflow: hidden;
}
.task[open] { border-color: var(--border-hover); }
.task.done { border-color: #26402c; }
.task-summary {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 20px;
    cursor: pointer;
    list-style: none;
    flex-wrap: wrap;
}
.task-summary::-webkit-details-marker { display: none; }
.task-num {
    font-family: var(--mono);
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--text-faint);
}
.task-title { font-weight: 600; flex: 1; min-width: 140px; }
.task-status {
    width: 18px;
    height: 18px;
    border-radius: 50%;
    border: 1px solid var(--border-hover);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 11px;
}
.task.done .task-status {
    background: #d0f0d6;
    border-color: #d0f0d6;
    color: #000;
}
.task.done .task-status::after { content: "✓"; }
.task-pts { font-family: var(--mono); font-size: 12px; margin-left: auto; }
.task-body { padding: 0 20px 20px; border-top: 1px solid var(--border); padding-top: 16px; }
.hint-box {
    margin: 16px 0;
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 10px 14px;
    background: var(--bg-elev);
}
.hint-box summary {
    font-family: var(--mono);
    font-size: 12px;
    color: var(--text-dim);
    cursor: pointer;
}
.hint-box p { margin: 10px 0 0; font-size: 13px; }
.question-block { margin-top: 18px; }
.answer-row { display: flex; gap: 10px; flex-wrap: wrap; }
.answer-row .answer-input { flex: 1; min-width: 200px; margin-bottom: 0; }
.answer-feedback { font-family: var(--mono); font-size: 13px; margin-top: 10px; }
.answer-feedback.ok { color: #d0f0d6; }
.answer-feedback.bad { color: #f3d0d4; }
.answer-row.shake { animation: shake .35s ease; }
@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-6px); }
    75% { transform: translateX(6px); }
}

.room-chip {
    position: sticky;
    top: 64px;
    z-index: 40;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 16px;
    padding: 8px 14px;
    background: var(--bg-elev);
    border: 1px solid var(--border-hover);
    border-radius: 999px;
    font-family: var(--mono);
    font-size: 12px;
    color: var(--text);
}
.room-chip:hover { background: #1a1d21; }

@media (max-width: 640px) {
    .site-header-inner {
        gap: 12px;
        padding-left: 18px;
        padding-right: 18px;
    }
    .brand-logo {
        height: 38px;
        max-width: 150px;
    }
    .site-main,
    .site-footer-inner,
    .page-home .site-main,
    .page-home .site-footer-inner,
    .page-room .site-main,
    .page-room .site-footer-inner {
        padding-left: 18px;
        padding-right: 18px;
    }
    .footer-social { gap: 10px 14px; }
}