/* ── Design tokens ─────────────────────────────────────────────────────── */
:root {
    --bg:           #f3f2ef;
    --fg:           #1a1a1a;
    --muted:        #78716c;
    --accent:       #c2410c;
    --accent-light: #ea580c;
    --accent-glow:  rgba(194,65,12,.1);
    --card:         #ffffff;
    --card-hover:   #fafaf9;
    --border:       #e7e5e4;
    --border-soft:  #f0efed;
    --border-strong:#d6d3d1;
    --error:        #dc2626;
    --error-bg:     rgba(220,38,38,.06);
    --success:      #16a34a;
    --success-bg:   rgba(22,163,74,.06);
    --radius:       0.75rem;
    --radius-sm:    0.5rem;
    --transition:   all .2s cubic-bezier(.4,0,.2,1);
}

/* ── Reset ─────────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
    background: var(--bg);
    color: var(--fg);
    font-family: 'DM Sans', -apple-system, BlinkMacSystemFont, sans-serif;
    min-height: 100vh;
    overflow-x: hidden;
    line-height: 1.6;
}

/* Dot grid */
body::before {
    content: '';
    position: fixed;
    inset: 0;
    background-image: radial-gradient(circle, #d6d3d1 0.8px, transparent 0.8px);
    background-size: 24px 24px;
    opacity: .4;
    z-index: 0;
    pointer-events: none;
}

/* Animated blobs */
.blob {
    position: fixed;
    border-radius: 50%;
    filter: blur(120px);
    pointer-events: none;
    z-index: 0;
}
.blob-1 {
    width: 500px; height: 500px;
    background: radial-gradient(circle, rgba(194,65,12,.06), transparent 70%);
    top: -100px; right: -80px;
    animation: blobFloat1 22s ease-in-out infinite;
}
.blob-2 {
    width: 400px; height: 400px;
    background: radial-gradient(circle, rgba(251,146,60,.06), transparent 70%);
    bottom: -60px; left: -100px;
    animation: blobFloat2 28s ease-in-out infinite;
}
.blob-3 {
    width: 300px; height: 300px;
    background: radial-gradient(circle, rgba(22,163,74,.04), transparent 70%);
    top: 40%; left: 30%;
    animation: blobFloat3 18s ease-in-out infinite;
}
@keyframes blobFloat1 { 0%,100%{ transform:translate(0,0) scale(1); } 50%{ transform:translate(-60px,50px) scale(1.1); } }
@keyframes blobFloat2 { 0%,100%{ transform:translate(0,0) scale(1); } 50%{ transform:translate(50px,-40px) scale(.9); } }
@keyframes blobFloat3 { 0%,100%{ transform:translate(0,0) scale(1); } 50%{ transform:translate(30px,-30px) scale(1.15); } }

/* ── Header ────────────────────────────────────────────────────────────── */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(243,242,239,.85);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border);
}
.header-inner {
    max-width: 72rem;
    margin: 0 auto;
    padding: 0 1rem;
    height: 3.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.logo-link {
    display: flex;
    align-items: center;
    gap: .625rem;
    text-decoration: none;
    flex-shrink: 0;
}
.logo-icon {
    width: 2rem; height: 2rem;
    border-radius: .5rem;
    display: flex; align-items: center; justify-content: center;
    background: var(--accent);
    color: #fff;
    flex-shrink: 0;
}
.logo-icon svg { width: 14px; height: 14px; fill: #fff; }
.logo-text {
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 700;
    font-size: 1.125rem;
    color: var(--fg);
}
.header-nav { display: flex; align-items: center; gap: .125rem; }

.nav-link {
    padding: .375rem .625rem;
    border-radius: .5rem;
    font-size: .8125rem;
    font-weight: 500;
    text-decoration: none;
    color: var(--fg);
    transition: background .15s;
    white-space: nowrap;
}
.nav-link:hover { background: rgba(0,0,0,.04); }
.nav-link-muted { color: var(--muted); }
.nav-link-muted:hover { color: var(--fg); }

/* Puzzles dropdown */
.puzzles-dropdown { position: relative; }
.puzzles-toggle {
    display: flex; align-items: center; gap: 4px;
    padding: .375rem .625rem;
    border-radius: .5rem;
    font-size: .8125rem; font-weight: 500;
    text-decoration: none; color: var(--fg);
    transition: background .15s; cursor: pointer;
    background: none; border: none;
    font-family: 'DM Sans', sans-serif; white-space: nowrap;
}
.puzzles-toggle:hover { background: rgba(0,0,0,.04); }
.chevron-down { font-size: 9px; opacity: .5; transition: transform .2s; }
.puzzles-dropdown.open .chevron-down { transform: rotate(180deg); }

.puzzles-menu {
    position: absolute; top: calc(100% + 6px); left: 0;
    min-width: 210px;
    background: var(--card); border: 1px solid var(--border);
    border-radius: 10px; box-shadow: 0 8px 30px rgba(0,0,0,.1);
    padding: 4px;
    opacity: 0; visibility: hidden;
    transform: translateY(-6px); transition: all .2s ease;
    z-index: 200; max-height: 80vh; overflow-y: auto;
}
.puzzles-dropdown.open .puzzles-menu {
    opacity: 1; visibility: visible; transform: translateY(0);
}
.puzzles-menu-label {
    padding: 6px 12px 4px;
    font-size: 10px; font-weight: 600; text-transform: uppercase;
    letter-spacing: .05em; color: var(--muted);
}
.puzzles-menu .puzzle-link {
    display: flex; align-items: center; gap: 10px;
    width: 100%; padding: 8px 12px;
    border-radius: 7px; font-size: 13.5px;
    font-family: 'DM Sans', sans-serif;
    color: var(--fg); cursor: pointer;
    transition: background .12s; text-decoration: none;
}
.puzzles-menu .puzzle-link:hover { background: var(--bg); }
.puzzles-menu .puzzle-link.active-puzzle { color: var(--accent); font-weight: 600; }
.puzzle-badge {
    display: inline-flex; align-items: center; justify-content: center;
    min-width: 32px; height: 20px;
    border-radius: 4px; font-size: 10px; font-weight: 700;
    font-family: 'Space Grotesk', sans-serif;
    background: var(--bg); color: var(--muted);
    flex-shrink: 0;
}
.active-puzzle .puzzle-badge { background: var(--accent-glow); color: var(--accent); }
.menu-divider { height: 1px; background: var(--border); margin: 4px 8px; }

/* Language dropdown */
.lang-dropdown { position: relative; margin-left: .25rem; }
.lang-toggle {
    display: flex; align-items: center; gap: 5px;
    padding: .35rem .55rem; border-radius: .5rem;
    font-size: .8125rem;
    border: 1px solid var(--border); background: var(--card); color: var(--muted);
    cursor: pointer; font-family: 'DM Sans', sans-serif; font-weight: 500;
}
.lang-toggle svg { width: 14px; height: 14px; flex-shrink: 0; }
.chevron { font-size: 9px; opacity: .5; }
.lang-menu {
    position: absolute; top: calc(100% + 6px); right: 0;
    min-width: 180px;
    background: var(--card); border: 1px solid var(--border);
    border-radius: 10px; box-shadow: 0 8px 30px rgba(0,0,0,.1);
    padding: 4px;
    opacity: 0; visibility: hidden;
    transform: translateY(-6px); transition: all .2s ease;
    z-index: 200; max-height: 400px; overflow-y: auto;
}
.lang-menu.open { opacity: 1; visibility: visible; transform: translateY(0); }
.lang-item {
    display: flex; align-items: center; gap: 10px;
    width: 100%; padding: 8px 12px;
    border-radius: 7px; font-size: 13.5px;
    font-family: 'DM Sans', sans-serif;
    color: var(--fg); text-decoration: none;
    transition: background .12s;
}
.lang-item:hover { background: var(--bg); }
.lang-item.active-lang { color: var(--accent); font-weight: 600; }

/* Mobile hamburger */
.mobile-menu-btn {
    display: none; align-items: center; justify-content: center;
    width: 36px; height: 36px;
    border-radius: 8px; border: 1px solid var(--border);
    background: var(--card); cursor: pointer; color: var(--fg);
    -webkit-tap-highlight-color: transparent;
}
.mobile-menu-btn svg { width: 18px; height: 18px; }
.mobile-overlay {
    display: none; position: fixed; inset: 0;
    background: rgba(0,0,0,.3); z-index: 150;
    backdrop-filter: blur(4px);
}
.mobile-overlay.open { display: block; }
.mobile-nav {
    display: none; position: fixed; top: 0; right: 0;
    width: min(300px, 85vw); height: 100%;
    background: var(--card); z-index: 200;
    box-shadow: -4px 0 30px rgba(0,0,0,.12);
    transform: translateX(100%);
    transition: transform .3s cubic-bezier(.22,1,.36,1);
    overflow-y: auto; padding: 1rem;
}
.mobile-nav.open { transform: translateX(0); }
.mobile-nav-header {
    display: flex; align-items: center; justify-content: space-between;
    margin-bottom: 1rem; padding-bottom: .75rem; border-bottom: 1px solid var(--border);
}
.mobile-nav-close {
    width: 32px; height: 32px; border-radius: 8px;
    border: 1px solid var(--border); background: none;
    cursor: pointer; display: flex; align-items: center; justify-content: center;
    color: var(--muted); font-size: 18px;
    -webkit-tap-highlight-color: transparent;
}
.mobile-nav-section { margin-bottom: 1rem; }
.mobile-nav-section-title {
    font-size: 10px; font-weight: 600; text-transform: uppercase;
    letter-spacing: .05em; color: var(--muted); padding: 4px 8px 6px;
}
.mobile-nav a, .mobile-nav .mob-close-link {
    display: flex; align-items: center; gap: 10px;
    width: 100%; padding: 10px 12px;
    border-radius: 8px; font-size: 14px;
    font-family: 'DM Sans', sans-serif;
    color: var(--fg); cursor: pointer;
    transition: background .12s; text-decoration: none; font-weight: 500;
}
.mobile-nav a:hover { background: var(--bg); }
.mobile-nav a.active-puzzle { color: var(--accent); font-weight: 600; }
.mob-lang-grid {
    display: grid; grid-template-columns: repeat(4, 1fr);
    gap: 4px; padding: 0 4px;
}
.mob-lang-btn {
    padding: 8px 4px; border-radius: 8px;
    border: 1px solid var(--border); background: none;
    font-size: 11px; font-family: 'DM Sans', sans-serif; font-weight: 500;
    color: var(--muted); cursor: pointer; text-align: center;
    transition: all .12s; text-decoration: none;
    display: flex; align-items: center; justify-content: center;
    -webkit-tap-highlight-color: transparent;
}
.mob-lang-btn:hover { border-color: var(--border-strong); color: var(--fg); }
.mob-lang-btn.active-lang { background: var(--accent); color: #fff; border-color: var(--accent); font-weight: 600; }

@media (max-width: 640px) {
    .desktop-only { display: none !important; }
    .mobile-menu-btn { display: flex; }
    .mobile-nav { display: block; }
}
@media (min-width: 641px) {
    .mobile-overlay, .mobile-nav { display: none !important; }
}

/* ── Main wrapper ──────────────────────────────────────────────────────── */
.main-wrap { position: relative; z-index: 10; }
.main-content {
    max-width: 72rem;
    margin: 0 auto;
    padding: 2rem 1rem 4rem;
}

/* ── Hero ──────────────────────────────────────────────────────────────── */
.hero { text-align: center; margin-bottom: 2rem; }
.hero h1 {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 2.5rem;
    font-weight: 700;
    letter-spacing: -.025em;
    color: var(--fg);
}
.hero h1 .accent { color: var(--accent); }
.hero p {
    margin-top: .75rem;
    font-size: .9375rem;
    max-width: 30rem;
    margin-left: auto; margin-right: auto;
    color: var(--muted);
    line-height: 1.6;
}
@media (min-width: 768px) {
    .hero h1 { font-size: 3rem; }
    .main-content { padding: 2.5rem 1rem 4rem; }
    .hero { margin-bottom: 2.5rem; }
}

/* ── Buttons ───────────────────────────────────────────────────────────── */
.btn {
    display: inline-flex; align-items: center; gap: 7px;
    padding: 10px 16px; border-radius: 10px;
    font-family: 'DM Sans', sans-serif; font-size: 13px; font-weight: 500;
    cursor: pointer; transition: all .2s; border: 1px solid transparent;
    white-space: nowrap; text-decoration: none;
    -webkit-tap-highlight-color: transparent;
}
.btn svg { width: 13px; height: 13px; flex-shrink: 0; }
.btn-primary { background: var(--accent); color: #fff; font-weight: 600; box-shadow: 0 2px 8px var(--accent-glow); }
.btn-primary:hover { background: var(--accent-light); transform: translateY(-1px); box-shadow: 0 4px 16px rgba(194,65,12,.2); color: #fff; }
.btn-primary svg { stroke: #fff; fill: none; }
.btn-secondary { background: var(--card); border-color: var(--border); color: var(--fg); box-shadow: 0 1px 3px rgba(0,0,0,.04); }
.btn-secondary:hover { border-color: var(--border-strong); background: var(--card-hover); }
.btn-danger { background: var(--card); border-color: rgba(220,38,38,.3); color: var(--error); }
.btn-danger:hover { background: var(--error-bg); }
.btn:active { transform: translateY(0) scale(.97); }
.btn:disabled { opacity: .35; pointer-events: none; }

/* ── Play section ──────────────────────────────────────────────────────── */
.play-section { display: flex; flex-direction: column; align-items: center; }
.controls-row {
    display: flex; align-items: center; gap: .5rem;
    margin-bottom: 1.25rem; flex-wrap: wrap; justify-content: center;
}
.diff-group { display: flex; gap: .375rem; }
.diff-btn {
    padding: 6px 14px; border-radius: 8px; font-size: 13px; font-weight: 500;
    cursor: pointer; transition: all .15s;
    background: var(--card); border: 1px solid var(--border); color: var(--muted);
    font-family: 'DM Sans', sans-serif;
    -webkit-tap-highlight-color: transparent;
}
.diff-btn.active { background: var(--accent); color: #fff; border-color: var(--accent); font-weight: 600; }
.diff-btn:not(.active):hover { border-color: var(--border-strong); color: var(--fg); }

/* ── Status & legend ───────────────────────────────────────────────────── */
.status-row {
    display: flex; align-items: center; gap: 1rem;
    margin-top: 1rem; flex-wrap: wrap; justify-content: center;
}
.status-item {
    display: flex; align-items: center; gap: 5px;
    font-size: 13px; color: var(--muted);
}
.status-item svg { width: 12px; height: 12px; flex-shrink: 0; }
.icon-accent { color: var(--accent); stroke: var(--accent); }
.icon-error  { color: var(--error);  stroke: var(--error); }
.value { color: var(--fg); font-weight: 600; font-family: 'Space Grotesk', sans-serif; }

.btn-row {
    display: flex; gap: .5rem; margin-top: 1.25rem;
    flex-wrap: wrap; justify-content: center;
}

.legend-row {
    display: flex; align-items: center; gap: 1.25rem;
    margin-top: 1rem; flex-wrap: wrap; justify-content: center;
}
.legend-item { display: inline-flex; align-items: center; gap: 5px; font-size: 12px; color: var(--muted); }
.legend-dot { width: 10px; height: 10px; border-radius: 3px; flex-shrink: 0; }

/* Speed slider */
.speed-control {
    margin-top: 1rem; width: 100%; max-width: 20rem; display: none;
}
.speed-header {
    display: flex; justify-content: space-between;
    font-size: .75rem; margin-bottom: .5rem; color: var(--muted);
}
.speed-slider {
    -webkit-appearance: none; appearance: none;
    width: 100%; height: 4px; background: var(--border); border-radius: 4px; outline: none;
}
.speed-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 20px; height: 20px; border-radius: 50%;
    background: var(--accent); cursor: pointer; box-shadow: 0 1px 4px rgba(0,0,0,.15);
}
.speed-slider::-moz-range-thumb {
    width: 20px; height: 20px; border-radius: 50%;
    background: var(--accent); cursor: pointer; border: none;
}

/* Solve stats */
.solve-stats {
    display: none; align-items: center; gap: 1rem;
    margin-top: .75rem; font-size: 12px; color: var(--muted);
    flex-wrap: wrap; justify-content: center;
}
.solve-stats.active { display: flex; }
.stat-val { font-weight: 600; font-family: 'Space Grotesk', sans-serif; color: var(--fg); }

/* ── How-to / Article sections ─────────────────────────────────────────── */
.how-section {
    margin-top: 3rem;
    max-width: 52rem;
    margin-left: auto; margin-right: auto;
}
.how-section h2 {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 1.5rem; font-weight: 700;
    margin-bottom: 1.25rem; color: var(--fg);
}
.article-card {
    background: var(--card); border: 1px solid var(--border);
    border-radius: 16px; box-shadow: 0 2px 12px rgba(0,0,0,.04);
    overflow: hidden; padding: 1.25rem;
}
@media (min-width: 768px) { .article-card { padding: 2rem; } }
.article-grid { display: grid; gap: 2rem; }
@media (min-width: 768px) { .article-grid { grid-template-columns: 1fr 1fr; } }
.article-card h3 {
    font-family: 'Space Grotesk', sans-serif; font-weight: 600; font-size: 1rem;
    margin-bottom: .75rem; display: flex; align-items: center; gap: .5rem; color: var(--fg);
}
.article-card p { color: var(--muted); line-height: 1.7; font-size: .9375rem; }
.step-badge {
    width: 1.5rem; height: 1.5rem; border-radius: .375rem;
    display: flex; align-items: center; justify-content: center;
    font-size: .75rem; color: #fff; font-weight: 700;
    background: var(--accent); flex-shrink: 0;
}
.rule-list { list-style: none; display: flex; flex-direction: column; gap: .5rem; }
.rule-list li {
    display: flex; align-items: flex-start; gap: .5rem;
    font-size: .875rem; line-height: 1.6; color: var(--muted);
}
.rule-list li .icon-check { margin-top: .25rem; font-size: .75rem; color: var(--success); flex-shrink: 0; }
.rule-list li .icon-bulb  { margin-top: .25rem; font-size: .75rem; color: var(--accent);  flex-shrink: 0; }
.rule-list li strong { color: var(--fg); }

.tip-box {
    margin-top: 1.5rem; padding: 1rem; border-radius: .75rem;
    background: var(--accent-glow); border: 1px solid rgba(194,65,12,.12);
    display: flex; align-items: flex-start; gap: .75rem;
}
.icon-wand { margin-top: .125rem; color: var(--accent); flex-shrink: 0; }
.tip-box p { font-size: .875rem; line-height: 1.6; color: var(--fg); }
.tip-box p strong { font-weight: 700; }

/* Diff info cards (generator page) */
.diff-cards {
    display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 1rem; margin-top: 1.5rem;
}
.diff-info-card {
    background: var(--bg); border: 1px solid var(--border);
    border-radius: 12px; padding: 1rem; text-align: center;
}
.diff-info-icon { font-size: 1.75rem; margin-bottom: .5rem; }
.diff-info-title { font-weight: 700; font-family: 'Space Grotesk',sans-serif; font-size: .9375rem; margin-bottom: .25rem; }
.diff-info-desc  { font-size: .8125rem; color: var(--muted); }

/* ── Number pad ────────────────────────────────────────────────────────── */
.num-pad {
    display: flex; gap: .5rem; margin-top: 1.25rem;
    flex-wrap: wrap; justify-content: center;
}
.num-btn {
    width: 46px; height: 46px;
    display: flex; align-items: center; justify-content: center;
    background: var(--card); border: 1px solid var(--border); border-radius: 10px;
    color: var(--fg); font-family: 'Space Grotesk', sans-serif;
    font-size: 19px; font-weight: 600; cursor: pointer;
    transition: all .15s; box-shadow: 0 1px 3px rgba(0,0,0,.04);
    -webkit-tap-highlight-color: transparent;
}
.num-btn:hover { background: var(--accent-glow); border-color: var(--accent); color: var(--accent); transform: translateY(-2px); box-shadow: 0 4px 12px var(--accent-glow); }
.num-btn:active { transform: translateY(0) scale(.93); }
.num-btn.depleted { opacity: .2; pointer-events: none; }

/* ── Footer ────────────────────────────────────────────────────────────── */
.site-footer { background: var(--card); border-top: 1px solid var(--border); }
.footer-inner { max-width: 72rem; margin: 0 auto; padding: 2rem 1rem; }
.footer-row { display: flex; flex-direction: column; align-items: center; gap: 1.5rem; }
@media (min-width: 768px) { .footer-row { flex-direction: row; justify-content: space-between; } }
.footer-logo { display: flex; align-items: center; gap: .625rem; text-decoration: none; }
.footer-logo-icon {
    width: 1.75rem; height: 1.75rem; border-radius: .375rem;
    display: flex; align-items: center; justify-content: center;
    background: var(--accent); color: #fff;
}
.footer-logo-icon svg { width: 12px; height: 12px; fill: #fff; }
.footer-logo-text { font-family: 'Space Grotesk', sans-serif; font-weight: 700; font-size: .875rem; color: var(--fg); }
.footer-links { display: flex; align-items: center; gap: 1.5rem; flex-wrap: wrap; justify-content: center; }
.footer-links a { color: var(--muted); text-decoration: none; transition: color .15s; font-size: 13.5px; }
.footer-links a:hover { color: var(--accent); }
.footer-bottom {
    margin-top: 1.5rem; padding-top: 1rem; text-align: center;
    font-size: .75rem; border-top: 1px solid var(--border); color: var(--muted);
}

/* ── Toast ─────────────────────────────────────────────────────────────── */
#toast-container {
    position: fixed; top: 68px; right: 12px; z-index: 1000;
    display: flex; flex-direction: column; gap: 8px; pointer-events: none;
}
.toast {
    padding: 10px 16px; border-radius: 10px; font-size: 13px; font-weight: 500;
    transform: translateX(120%);
    transition: transform .35s cubic-bezier(.22,1,.36,1);
    backdrop-filter: blur(16px); max-width: 300px; pointer-events: auto;
    box-shadow: 0 4px 16px rgba(0,0,0,.08); font-family: 'DM Sans', sans-serif;
}
.toast.show { transform: translateX(0); }
.toast-info    { background: rgba(194,65,12,.08);  border: 1px solid rgba(194,65,12,.18);  color: var(--accent); }
.toast-success { background: rgba(22,163,74,.08);  border: 1px solid rgba(22,163,74,.18);  color: var(--success); }
.toast-error   { background: rgba(220,38,38,.08);  border: 1px solid rgba(220,38,38,.18);  color: var(--error); }

/* ── Coming soon ───────────────────────────────────────────────────────── */
.coming-soon-card {
    max-width: 52rem; margin: 0 auto 2rem;
    background: var(--card); border: 1px solid var(--border);
    border-radius: 16px; padding: 3rem 2rem; text-align: center;
    box-shadow: 0 2px 12px rgba(0,0,0,.04);
}
.coming-soon-badge {
    display: inline-flex; align-items: center; justify-content: center;
    width: 5rem; height: 5rem; border-radius: 1rem;
    font-family: 'Space Grotesk', sans-serif; font-size: 2rem; font-weight: 700;
    background: var(--accent-glow); color: var(--accent); border: 2px solid rgba(194,65,12,.2);
    margin-bottom: 1.5rem;
}
.coming-soon-content h2 {
    font-family: 'Space Grotesk', sans-serif; font-size: 1.5rem; font-weight: 700;
    margin-bottom: .75rem; color: var(--fg);
}
.coming-soon-content p { color: var(--muted); max-width: 36rem; margin: 0 auto 2rem; line-height: 1.7; }
.coming-soon-actions { display: flex; gap: .75rem; justify-content: center; flex-wrap: wrap; }

/* ── Focus & accessibility ──────────────────────────────────────────────── */
.btn:focus-visible, .num-btn:focus-visible, .diff-btn:focus-visible {
    outline: 2px solid var(--accent); outline-offset: 2px;
}

/* ── Scrollbar ─────────────────────────────────────────────────────────── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border-strong); border-radius: 3px; }
html { scroll-behavior: smooth; }

/* ── Responsive ────────────────────────────────────────────────────────── */
@media (max-width: 480px) {
    .hero h1 { font-size: 1.875rem; }
    .hero p  { font-size: .875rem; }
    .main-content { padding: 1.5rem .75rem 3rem; }
    .num-btn { width: 40px; height: 40px; font-size: 17px; border-radius: 8px; }
    .num-pad { gap: 6px; }
    .btn { padding: 9px 12px; font-size: 12px; gap: 5px; }
    .btn svg { width: 11px; height: 11px; }
    .diff-btn { padding: 5px 12px; font-size: 12px; }
    .btn-row { gap: 6px; }
    .status-row { gap: .75rem; }
    .controls-row { gap: .5rem; }
    .how-section { margin-top: 2rem; }
}
@media (max-width: 360px) {
    .num-btn { width: 34px; height: 34px; font-size: 15px; }
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}

@media print {
    .site-header, .site-footer, .btn-row, .controls-row,
    .num-pad, .speed-control, .solve-stats, .legend-row,
    .how-section, .blob, #toast-container { display: none !important; }
    body::before { display: none; }
    .main-content { padding: 0; }
}