/* Maths Arcade - student pages (home, worksheet, how to play).
   Arcade look for headings; a plain, readable font for everything students read. */

@import url('https://fonts.googleapis.com/css2?family=Press+Start+2P&display=swap');

:root {
    --ink: #1f2937;
    --muted: #4b5563;
    --card: #ffffff;
    --accent: #2563eb;
    --gold: #fbbf24;
    --ok: #15803d;
    --ok-bg: #dcfce7;
    --bad: #b91c1c;
    --bad-bg: #fee2e2;
    --near: #a16207;
    --near-bg: #fef9c3;
    --radius: 14px;
    --pixel: 'Press Start 2P', monospace;
}

* { box-sizing: border-box; }

body {
    margin: 0;
    min-height: 100vh;
    font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
    font-size: 17px;
    line-height: 1.5;
    color: var(--ink);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%) fixed;
}

.stars { position: fixed; inset: 0; pointer-events: none; z-index: 0; }
.star { position: absolute; background: #fff; border-radius: 50%; animation: twinkle 3s infinite; }
@keyframes twinkle { 0%, 100% { opacity: .3; } 50% { opacity: 1; } }
@media (prefers-reduced-motion: reduce) { .star { animation: none; } }

/* ---------- header ---------- */
.site-header {
    position: relative;
    z-index: 2;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 12px;
    padding: 14px 20px;
    background: rgba(17, 24, 39, .55);
    border-bottom: 3px solid var(--gold);
}
.site-header .brand {
    font-family: var(--pixel);
    font-size: 18px;
    color: #fff;
    text-decoration: none;
    text-shadow: 0 0 10px rgba(251, 191, 36, .6);
}
.site-header nav { display: flex; gap: 8px; flex-wrap: wrap; }
.site-header nav a {
    color: #fff;
    text-decoration: none;
    font-weight: 600;
    padding: 6px 12px;
    border-radius: 999px;
}
.site-header nav a:hover, .site-header nav a:focus-visible { background: rgba(255, 255, 255, .18); }

main {
    position: relative;
    z-index: 1;
    max-width: 860px;
    margin: 0 auto;
    padding: 24px 16px 64px;
}

.panel {
    background: var(--card);
    border-radius: var(--radius);
    padding: 20px 22px;
    margin-bottom: 18px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, .18);
}
.panel h2, .pixel-title {
    font-family: var(--pixel);
    font-size: 15px;
    line-height: 1.6;
    color: #4c1d95;
    margin: 0 0 12px;
}
.hidden { display: none !important; }

/* ---------- home ---------- */
.hero { text-align: center; color: #fff; margin: 8px 0 22px; }
.hero h1 { font-family: var(--pixel); font-size: 22px; line-height: 1.5; margin: 0 0 10px; text-shadow: 0 3px 0 rgba(0, 0, 0, .25); }
.hero p { margin: 0; font-size: 18px; }

.steps { display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 12px; margin: 0; padding: 0; list-style: none; counter-reset: step; }
.steps li { background: #f5f3ff; border-radius: 10px; padding: 12px 12px 12px 46px; position: relative; }
.steps li::before {
    counter-increment: step; content: counter(step);
    position: absolute; left: 12px; top: 12px; width: 24px; height: 24px; border-radius: 50%;
    background: #7c3aed; color: #fff; font-weight: 700; display: grid; place-items: center; font-size: 14px;
}

.worksheet-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 14px; }
.worksheet-card {
    display: block;
    background: var(--card);
    border-radius: var(--radius);
    padding: 18px;
    color: var(--ink);
    text-decoration: none;
    border: 3px solid transparent;
    box-shadow: 0 8px 24px rgba(0, 0, 0, .18);
    transition: transform .15s, border-color .15s;
}
.worksheet-card:hover, .worksheet-card:focus-visible { transform: translateY(-3px); border-color: var(--gold); outline: none; }
.worksheet-card h3 { margin: 0 0 8px; font-size: 19px; }
.card-tags { display: flex; gap: 6px; margin-bottom: 8px; }
.badge { font-size: 13px; font-weight: 700; padding: 2px 10px; border-radius: 999px; background: #e0e7ff; color: #3730a3; text-transform: capitalize; }
.badge-easy { background: #dcfce7; color: #166534; }
.badge-medium { background: #fef3c7; color: #92400e; }
.badge-difficult, .badge-hard { background: #fee2e2; color: #991b1b; }
.card-topic, .card-meta { margin: 0; color: var(--muted); font-size: 15px; }
.card-best { margin: 8px 0 0; font-weight: 700; color: #92400e; }

.tools { display: flex; gap: 10px; flex-wrap: wrap; }
.tool-link {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 10px 14px; border-radius: 10px; background: #f5f3ff; color: #4c1d95; font-weight: 600; text-decoration: none;
}
.tool-link:hover { background: #ede9fe; }

/* ---------- worksheet ---------- */
.sheet-head h1 { font-family: var(--pixel); font-size: 17px; line-height: 1.6; color: #4c1d95; margin: 0 0 6px; }
.sheet-meta { margin: 0; color: var(--muted); }

.scorebar { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; }
.scorebar .score { font-weight: 800; font-size: 20px; color: #92400e; white-space: nowrap; }
.scorebar .progress { flex: 1; min-width: 180px; }
.progress-track { height: 12px; border-radius: 999px; background: #e5e7eb; overflow: hidden; margin-top: 4px; }
.progress-fill { height: 100%; width: 0; background: linear-gradient(90deg, #22c55e, #16a34a); transition: width .4s; }
.progress-text { font-size: 15px; color: var(--muted); }

.how-to-answer summary { cursor: pointer; font-weight: 700; color: #4c1d95; }
.how-to-answer table { border-collapse: collapse; margin-top: 10px; width: 100%; }
.how-to-answer td { padding: 6px 8px; border-top: 1px solid #ede9fe; vertical-align: top; }
.how-to-answer kbd {
    display: inline-block; min-width: 1.6em; text-align: center; padding: 1px 6px; border-radius: 6px;
    border: 1px solid #c4b5fd; background: #f5f3ff; font-family: ui-monospace, Menlo, monospace; font-weight: 700;
}

.question-card { scroll-margin-top: 16px; border: 3px solid transparent; }
.question-card[data-state="correct"] { border-color: #22c55e; }
.question-card[data-state="revealed"] { border-color: #f87171; }
.question-head { display: flex; justify-content: space-between; align-items: center; gap: 10px; }
.question-head h3 { margin: 0; font-family: var(--pixel); font-size: 13px; color: #4c1d95; }
.status-badge { font-size: 14px; font-weight: 700; padding: 3px 10px; border-radius: 999px; background: #f3f4f6; color: var(--muted); }
.status-badge.correct { background: var(--ok-bg); color: var(--ok); }
.status-badge.trying { background: var(--near-bg); color: var(--near); }
.status-badge.revealed { background: var(--bad-bg); color: var(--bad); }
.question-prompt { font-size: 22px; margin: 14px 0 6px; overflow-x: auto; }

.answer-label { font-weight: 700; margin: 6px 0 6px; }
.answer-row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
math-field.answer-box {
    min-width: 200px;
    flex: 1 1 220px;
    font-size: 26px;
    padding: 8px 12px;
    border: 3px solid #a78bfa;
    border-radius: 12px;
    background: #fff;
}
math-field.answer-box:focus-within { border-color: var(--accent); box-shadow: 0 0 0 4px rgba(37, 99, 235, .2); outline: none; }
math-field.answer-box.correct { border-color: #22c55e; background: #f0fdf4; }
math-field.answer-box.incorrect { border-color: #ef4444; background: #fef2f2; }
math-field.answer-box.nearly { border-color: #eab308; background: #fefce8; }
math-field.answer-box.muted { opacity: .45; }
/* We give students one clearly labelled keyboard button instead of MathLive's small icons */
math-field::part(menu-toggle), math-field::part(virtual-keyboard-toggle) { display: none; }

.root-box { display: flex; align-items: center; gap: 8px; flex: 1 1 200px; }
.root-label { font-weight: 800; font-size: 20px; white-space: nowrap; }
.root-box math-field.answer-box { min-width: 120px; }
.no-solutions { display: inline-flex; align-items: center; gap: 8px; margin-top: 10px; font-weight: 600; cursor: pointer; }
.no-solutions input { width: 20px; height: 20px; }

.keyboard-btn {
    display: inline-flex; align-items: center; gap: 6px;
    padding: 10px 14px; border-radius: 10px; border: 2px solid #7c3aed; background: #f5f3ff; color: #4c1d95;
    font: inherit; font-weight: 700; cursor: pointer;
}
.keyboard-btn:hover { background: #ede9fe; }

.working { margin-top: 12px; }
.working summary { cursor: pointer; color: var(--muted); font-weight: 600; }
math-field.working-box { width: 100%; min-height: 70px; margin-top: 8px; border-style: dashed; border-color: #cbd5e1; font-size: 22px; }

.question-actions { display: flex; align-items: center; gap: 14px; margin-top: 16px; flex-wrap: wrap; }
.btn-check, .btn-big {
    padding: 12px 26px; border: 0; border-radius: 12px; cursor: pointer;
    font: inherit; font-weight: 800; color: #fff; background: linear-gradient(135deg, #2563eb, #7c3aed);
    box-shadow: 0 4px 0 #3730a3;
}
.btn-check:active, .btn-big:active { transform: translateY(2px); box-shadow: 0 2px 0 #3730a3; }
.btn-check:disabled { opacity: .45; cursor: default; transform: none; }
.btn-big { width: 100%; font-size: 18px; }
.btn-secondary { background: #f3f4f6; color: var(--ink); box-shadow: 0 4px 0 #d1d5db; }
.tries { color: var(--muted); font-size: 15px; }

.feedback { margin-top: 12px; padding: 12px 14px; border-radius: 10px; display: flex; gap: 10px; align-items: flex-start; flex-wrap: wrap; font-weight: 600; }
.feedback.correct { background: var(--ok-bg); color: var(--ok); }
.feedback.incorrect { background: var(--bad-bg); color: var(--bad); }
.feedback.nearly { background: var(--near-bg); color: var(--near); }
.feedback.info { background: #e0f2fe; color: #075985; }
.model-answer { flex-basis: 100%; color: var(--ink); background: #fff; border-radius: 8px; padding: 6px 10px; font-size: 20px; }

.results h2 { margin-bottom: 6px; }
.results-score { font-size: 28px; font-weight: 800; color: #92400e; margin: 0; }
.results p { margin: 6px 0; }
.load-error { color: #fff; font-size: 18px; }
.load-error a { color: var(--gold); }

/* ---------- guide ---------- */
.guide h2 { margin-top: 0; }
.guide table { border-collapse: collapse; width: 100%; }
.guide th, .guide td { text-align: left; padding: 8px; border-top: 1px solid #ede9fe; vertical-align: top; }
.guide kbd {
    display: inline-block; min-width: 1.6em; text-align: center; padding: 1px 6px; border-radius: 6px;
    border: 1px solid #c4b5fd; background: #f5f3ff; font-family: ui-monospace, Menlo, monospace; font-weight: 700;
}

@media (max-width: 560px) {
    body { font-size: 16px; }
    .hero h1 { font-size: 17px; }
    .site-header .brand { font-size: 14px; }
    .question-prompt { font-size: 19px; }
    math-field.answer-box { font-size: 22px; }
}