/* Code Arena — public UI styles. C# track color: #7c3aed (light) / #a78bfa (dark) */
:root {
    /* Light mode (default) — softened contrast for easier reading. */
    --arena-bg: #f5f7fa;          /* lighter page bg */
    --arena-panel: #fbfcfd;       /* off-white panel so the bg/panel separation is gentle */
    --arena-panel-2: #eef2f7;     /* slate-100/200 mix — used for pill / inactive backgrounds */
    --arena-border: #e2e8f0;      /* slate-200 — softer than slate-300 */
    --arena-border-strong: #cbd5e1;
    --arena-text: #334155;        /* slate-700, ~9:1 on white (was slate-900) */
    --arena-muted: #64748b;       /* slate-500, ~5:1 on white */
    --arena-accent: #7c3aed;      /* violet-600, softer than violet-700 */
    --arena-accent-2: #6d28d9;    /* violet-700 — used for links / "is-me" text */
    --arena-on-accent: #ffffff;
    --arena-good: #16a34a;        /* green-600 */
    --arena-good-soft: #dcfce7;
    --arena-warn: #d97706;        /* amber-600 */
    --arena-warn-soft: #fef3c7;
    --arena-bad: #dc2626;         /* red-600 */
    --arena-bad-soft: #fee2e2;
    --arena-pill-type: #2563eb;   /* blue-600 */
    --arena-accent-soft: #f3f0ff; /* violet-50 — gentler tint */
    --arena-boss-grad: linear-gradient(135deg, #f3f0ff, #fdfaff);
    --arena-shadow: 0 1px 2px rgba(15,23,42,0.03), 0 1px 2px rgba(15,23,42,0.04);
}

[data-theme="dark"] {
    --arena-bg: #0d1117;
    --arena-panel: #161b22;
    --arena-panel-2: #1c222b;
    --arena-border: #30363d;
    --arena-border-strong: #4b5563;
    --arena-text: #e6edf3;
    --arena-muted: #9ca3af;       /* slightly lifted from #8b949e for AA on dark panel */
    --arena-accent: #a78bfa;
    --arena-accent-2: #c4b5fd;
    --arena-on-accent: #1a1029;
    --arena-good: #3fb950;
    --arena-good-soft: rgba(63,185,80,0.15);
    --arena-warn: #d29922;
    --arena-warn-soft: rgba(210,153,34,0.15);
    --arena-bad: #f85149;
    --arena-bad-soft: rgba(248,81,73,0.12);
    --arena-pill-type: #79c0ff;
    --arena-accent-soft: rgba(167,139,250,0.14);
    --arena-boss-grad: linear-gradient(135deg, rgba(167,139,250,0.18), rgba(167,139,250,0.04));
    --arena-shadow: none;
}

/* Force shell to constrain content even when host theme injects full-width rules
   like `.blog-content > * { width: 100% }`. The !important flags + explicit
   box-sizing keep cards from spilling past the viewport on wide screens. */
.arena-shell {
    display: block !important;
    width: 100% !important;
    max-width: 1200px !important;
    margin: 24px auto !important;
    padding: 0 16px !important;
    box-sizing: border-box !important;
    color: var(--arena-text);
    overflow-x: clip;
}
.arena-shell *, .arena-shell *::before, .arena-shell *::after { box-sizing: border-box; }
.arena-shell a { color: var(--arena-accent-2); text-decoration: none; }
.arena-shell a:hover { text-decoration: underline; }
/* The challenge detail page wants a narrower reading column */
.arena-shell.arena-challenge-page { max-width: 880px !important; }

.arena-header { display: flex; justify-content: space-between; align-items: center; gap: 24px; padding: 20px 24px; background: var(--arena-panel); border: 1px solid var(--arena-border); border-radius: 12px; margin-bottom: 20px; box-shadow: var(--arena-shadow); }
.arena-header h1 { margin: 0; font-size: 28px; }
.arena-breadcrumb { color: var(--arena-muted); font-size: 13px; margin-top: 4px; }
.arena-xp { min-width: 280px; }
.arena-xp-label { color: var(--arena-accent); font-weight: 600; margin-bottom: 6px; }
.arena-xp-bar { height: 10px; background: var(--arena-panel-2); border-radius: 6px; overflow: hidden; }
.arena-xp-bar > span { display: block; height: 100%; background: linear-gradient(90deg, var(--arena-accent), var(--arena-accent-2)); }
.arena-xp-num { color: var(--arena-muted); font-size: 12px; margin-top: 4px; }

.arena-tabs { display: flex; gap: 8px; margin-bottom: 16px; }
.arena-tab { display: flex; flex-direction: column; padding: 10px 16px; background: var(--arena-panel); border: 1px solid var(--arena-border); border-radius: 8px; min-width: 160px; cursor: pointer; box-shadow: var(--arena-shadow); }
.arena-tab.is-active { border-color: var(--arena-accent); border-width: 2px; padding: 9px 15px; }
.arena-tab.is-disabled { opacity: 0.45; cursor: not-allowed; }
.arena-tab .dot { display: inline-block; width: 10px; height: 10px; border-radius: 50%; margin-right: 8px; vertical-align: middle; }
.arena-tab .dot-csharp { background: #a78bfa; }
.arena-tab .dot-py { background: #fbbf24; }
.arena-tab .dot-go { background: #22d3ee; }
.arena-tab .dot-sql { background: #34d399; }
.arena-tab small { color: var(--arena-muted); margin-top: 4px; }
.arena-tab { text-decoration: none; color: inherit; }
.arena-tab:hover:not(.is-active) { border-color: var(--arena-accent); }

.arena-grid { display: grid; grid-template-columns: minmax(0, 2fr) minmax(0, 1fr); gap: 20px; }
@media (max-width: 880px) { .arena-grid { grid-template-columns: 1fr; } }
.arena-col-main, .arena-col-side { display: flex; flex-direction: column; gap: 16px; }
.arena-section-title { margin: 8px 0 4px; font-size: 18px; }

.arena-week { display: flex; gap: 6px; }
.arena-day { display: inline-flex; align-items: center; justify-content: center; width: 28px; height: 28px; border-radius: 6px; background: var(--arena-panel); border: 1px solid var(--arena-border); color: var(--arena-muted); font-size: 12px; font-weight: 600; }
.arena-day.is-on { background: var(--arena-accent); color: var(--arena-on-accent); border-color: var(--arena-accent); }

.arena-path { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 8px; }
.arena-path-item { display: grid; grid-template-columns: 36px minmax(0, 1fr) auto; align-items: center; gap: 12px; padding: 12px 14px; background: var(--arena-panel); border: 1px solid var(--arena-border); border-radius: 8px; box-shadow: var(--arena-shadow); min-width: 0; }
.arena-path-item > * { min-width: 0; }
.arena-path-desc { overflow: hidden; text-overflow: ellipsis; }
.arena-path-item.is-current { border-color: var(--arena-accent); }
.arena-path-item.is-locked { opacity: 0.55; }
.arena-path-bullet { width: 28px; height: 28px; border-radius: 50%; background: var(--arena-panel-2); display: flex; align-items: center; justify-content: center; font-weight: 700; }
.arena-path-item.is-done .arena-path-bullet { background: var(--arena-good); color: var(--arena-on-accent); }
.arena-path-item.is-current .arena-path-bullet { background: var(--arena-accent); color: var(--arena-on-accent); }
.arena-path-title { font-weight: 600; }
.arena-path-tag { color: var(--arena-muted); font-weight: 400; font-size: 12px; margin-left: 6px; }
.arena-path-desc { color: var(--arena-muted); font-size: 13px; }
.arena-path-xp { color: var(--arena-accent); font-weight: 600; }

.arena-types { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; }
@media (max-width: 720px) { .arena-types { grid-template-columns: repeat(2, 1fr); } }
.arena-type { background: var(--arena-panel); border: 1px solid var(--arena-border); border-radius: 8px; padding: 12px; box-shadow: var(--arena-shadow); }
.arena-type-icon { font-size: 22px; margin-bottom: 6px; }
.arena-type-title { font-weight: 600; }
.arena-type-desc { color: var(--arena-muted); font-size: 13px; }

.arena-challenges { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; }
@media (max-width: 720px) { .arena-challenges { grid-template-columns: 1fr; } }
.arena-challenge { background: var(--arena-panel); border: 1px solid var(--arena-border); border-radius: 8px; padding: 14px; box-shadow: var(--arena-shadow); }
.arena-challenge.is-done { border-color: var(--arena-good); }
.arena-challenge h3 { margin: 8px 0 4px; font-size: 16px; color: var(--arena-text); }
.arena-challenge-head { display: flex; gap: 6px; flex-wrap: wrap; }
.arena-challenge-meta { color: var(--arena-muted); font-size: 12px; }

.arena-pill { display: inline-block; padding: 2px 8px; border-radius: 999px; font-size: 11px; font-weight: 700; background: var(--arena-panel-2); color: var(--arena-text); border: 1px solid var(--arena-border-strong); }
.pill-easy { color: var(--arena-good); border-color: var(--arena-good); background: var(--arena-good-soft); }
.pill-medium { color: var(--arena-warn); border-color: var(--arena-warn); background: var(--arena-warn-soft); }
.pill-hard { color: var(--arena-bad); border-color: var(--arena-bad); background: var(--arena-bad-soft); }
.pill-boss { color: var(--arena-accent-2); border-color: var(--arena-accent); background: var(--arena-accent-soft); }
.pill-level { color: var(--arena-accent-2); }
.pill-type { color: var(--arena-pill-type); border-color: var(--arena-pill-type); }
.pill-tag { color: var(--arena-text); }

.arena-badges { display: grid; grid-template-columns: repeat(auto-fill, minmax(110px, 1fr)); gap: 10px; }
.arena-badge { background: var(--arena-panel); border: 1px solid var(--arena-border); border-radius: 8px; padding: 12px; text-align: center; box-shadow: var(--arena-shadow); }
.arena-badge.is-off { opacity: 0.55; }
.arena-badge-hex { display: block; width: 36px; height: 36px; margin: 0 auto 6px; background: var(--arena-accent); clip-path: polygon(50% 0,100% 25%,100% 75%,50% 100%,0 75%,0 25%); }
.arena-badge.is-off .arena-badge-hex { background: var(--arena-border); }
.arena-badge-label { font-size: 12px; }

.arena-card { display: block; background: var(--arena-panel); border: 1px solid var(--arena-border); border-radius: 8px; padding: 14px; margin-bottom: 12px; color: var(--arena-text) !important; text-decoration: none !important; box-shadow: var(--arena-shadow); }
.arena-card-weekly { border-color: var(--arena-accent); }
.arena-card-boss { border-color: var(--arena-accent-2); background: var(--arena-boss-grad); }
.arena-card-empty { opacity: 0.6; }
.arena-card-meta { color: var(--arena-warn); font-size: 12px; font-weight: 600; }
.arena-card-boss-meta { color: var(--arena-accent-2); }
.arena-card-tags { display: flex; gap: 6px; flex-wrap: wrap; margin-top: 8px; }
.arena-card-reward { color: var(--arena-accent-2); font-size: 12px; margin-top: 8px; }
.arena-side-title { margin: 8px 0 4px; font-size: 14px; color: var(--arena-muted); text-transform: uppercase; letter-spacing: 0.05em; }

.arena-leaderboard { list-style: none; padding: 0; margin: 0; background: var(--arena-panel); border: 1px solid var(--arena-border); border-radius: 8px; box-shadow: var(--arena-shadow); }
.arena-leaderboard li { display: grid; grid-template-columns: 32px 28px 1fr auto; gap: 10px; align-items: center; padding: 8px 12px; border-bottom: 1px solid var(--arena-border); font-size: 13px; }
.arena-leaderboard li:last-child { border-bottom: 0; }
.arena-leaderboard li.is-me { background: var(--arena-accent-soft); color: var(--arena-accent-2); }
.arena-leaderboard .rank { color: var(--arena-muted); }
.arena-leaderboard .avatar { width: 24px; height: 24px; border-radius: 50%; background: var(--arena-panel-2); display: inline-flex; align-items: center; justify-content: center; font-size: 11px; font-weight: 600; }
.arena-leaderboard .xp { color: var(--arena-accent); font-weight: 600; }

.arena-cta { display: inline-block; padding: 10px 18px; background: var(--arena-accent); color: var(--arena-on-accent) !important; font-weight: 700; border-radius: 6px; border: 0; text-decoration: none !important; cursor: pointer; }
.arena-cta:hover { background: var(--arena-accent-2); }

.arena-empty { color: var(--arena-muted); padding: 20px; text-align: center; background: var(--arena-panel); border: 1px dashed var(--arena-border); border-radius: 8px; }

/* Challenge page (max-width handled in shell rule above) */
.arena-back { display: inline-block; margin-bottom: 12px; color: var(--arena-muted); }
.arena-challenge-header { padding: 20px 24px; background: var(--arena-panel); border: 1px solid var(--arena-border); border-radius: 12px; margin-bottom: 16px; box-shadow: var(--arena-shadow); }
.arena-challenge-header h1 { margin: 8px 0; }
.arena-challenge-pills { display: flex; gap: 6px; flex-wrap: wrap; }
.arena-challenge-stats { color: var(--arena-muted); font-size: 13px; }
.arena-done-tag { color: var(--arena-good); font-weight: 600; margin-left: 8px; }
.arena-problem, .arena-starter, .arena-submit { background: var(--arena-panel); border: 1px solid var(--arena-border); border-radius: 8px; padding: 16px 20px; margin-bottom: 12px; box-shadow: var(--arena-shadow); }
.arena-problem h2, .arena-starter h2, .arena-submit h2 { margin-top: 0; font-size: 16px; }
.arena-prose { white-space: pre-wrap; font-family: inherit; color: var(--arena-text); }
.arena-starter pre, .arena-submit pre { background: var(--arena-bg); padding: 12px; border-radius: 6px; overflow: auto; }
#arena-answer { width: 100%; min-height: 140px; background: var(--arena-bg); color: var(--arena-text); border: 1px solid var(--arena-border); border-radius: 6px; padding: 10px; font-family: ui-monospace, SFMono-Regular, Consolas, monospace; }
.arena-submit-row { display: flex; justify-content: space-between; align-items: center; margin-top: 10px; gap: 12px; flex-wrap: wrap; }
.arena-hints { display: flex; gap: 6px; flex-wrap: wrap; }
.arena-hint-btn { background: var(--arena-panel-2); color: var(--arena-text); border: 1px solid var(--arena-border-strong); border-radius: 6px; padding: 6px 10px; font-size: 12px; font-weight: 600; cursor: pointer; }
.arena-hint-btn:disabled { opacity: 0.5; cursor: not-allowed; }
.arena-result { margin-top: 12px; padding: 12px; border-radius: 6px; }
.arena-result.is-pass { background: var(--arena-good-soft); border: 1px solid var(--arena-good); }
.arena-result.is-fail { background: var(--arena-bad-soft); border: 1px solid var(--arena-bad); }
.arena-hint-out { margin-top: 10px; padding: 10px 12px; background: var(--arena-panel-2); border-left: 3px solid var(--arena-accent); border-radius: 4px; }


/* ===== Mobile / responsive (<=720px) ===== */
@media (max-width: 720px) {
    .arena-shell { margin: 12px auto !important; padding: 0 12px !important; }

    /* Header stacks vertically; XP bar goes full-width under the title. */
    .arena-header { flex-direction: column; align-items: flex-start; gap: 12px; padding: 16px; }
    .arena-header h1 { font-size: 22px; line-height: 1.25; }
    .arena-breadcrumb { font-size: 12px; }
    .arena-xp { min-width: 0; width: 100%; }

    /* Track tabs become a horizontal scroll strip so all 4 fit on narrow screens
       without wrapping awkwardly or shrinking unreadably. */
    .arena-tabs {
        gap: 6px;
        margin-bottom: 12px;
        overflow-x: auto;
        flex-wrap: nowrap;
        -webkit-overflow-scrolling: touch;
        scrollbar-width: none;
        padding-bottom: 4px;
    }
    .arena-tabs::-webkit-scrollbar { display: none; }
    .arena-tab {
        min-width: 0;
        flex: 0 0 auto;
        padding: 8px 12px;
        font-size: 13px;
    }
    .arena-tab.is-active { padding: 7px 11px; }
    .arena-tab small { font-size: 11px; }

    /* Tighter section spacing/typography. */
    .arena-section-title { font-size: 16px; }
    .arena-col-main, .arena-col-side { gap: 12px; }

    /* Skill-path rows: drop bullet column and let title wrap naturally; XP sits below. */
    .arena-path-item {
        grid-template-columns: 28px minmax(0, 1fr);
        grid-template-rows: auto auto;
        gap: 8px 10px;
        padding: 10px 12px;
    }
    .arena-path-bullet { width: 24px; height: 24px; font-size: 12px; }
    .arena-path-xp { grid-column: 2; font-size: 12px; }
    .arena-path-title { font-size: 14px; }
    .arena-path-desc { font-size: 12px; white-space: normal; }

    /* Challenge cards: a touch tighter. */
    .arena-challenge { padding: 12px; }
    .arena-challenge h3 { font-size: 15px; }

    /* Leaderboard: drop avatar column on phones, give name room to truncate. */
    .arena-leaderboard li {
        grid-template-columns: 24px 1fr auto;
        gap: 8px;
        padding: 8px 10px;
    }
    .arena-leaderboard .avatar { display: none; }
    .arena-leaderboard li > .name,
    .arena-leaderboard li > span:nth-child(3) {
        overflow: hidden;
        text-overflow: ellipsis;
        white-space: nowrap;
        min-width: 0;
    }

    /* Challenge detail page on mobile. */
    .arena-challenge-header { padding: 14px 16px; }
    .arena-challenge-header h1 { font-size: 20px; }
    .arena-problem, .arena-starter, .arena-submit { padding: 12px 14px; }
    .arena-prose { font-size: 14px; }
    .arena-starter pre, .arena-submit pre { font-size: 12px; padding: 10px; }
    #arena-answer { min-height: 110px; font-size: 13px; }
    .arena-submit-row { flex-direction: column; align-items: stretch; gap: 8px; }
    .arena-submit-row .arena-cta { text-align: center; width: 100%; }
    .arena-hints { justify-content: flex-start; }

    /* Type-card grid: single column below 480, two columns 481-720 (already two via base rule). */
    .arena-week { flex-wrap: wrap; }
}

@media (max-width: 480px) {
    .arena-types { grid-template-columns: 1fr; }
    .arena-badges { grid-template-columns: repeat(auto-fill, minmax(90px, 1fr)); }
    .arena-header h1 { font-size: 20px; }
    .arena-tab { padding: 7px 10px; font-size: 12px; }
}
.arena-guest-note { background: var(--arena-accent-soft); border: 1px solid var(--arena-border); color: var(--arena-text); padding: 10px 12px; border-radius: 6px; font-size: 13px; margin-bottom: 10px; }