:root {
    
    --bg-deep:    #080c16;
    --bg-panel:   #0f1524;
    --bg-surface: #161d30;
    --bg-raised:  #1c2540;
    --bg-glass:   rgba(15, 21, 36, .82);

    
    --border:       rgba(148, 163, 184, .1);
    --border-focus: rgba(129, 140, 248, .4);

    
    --text:       #e2e8f0;
    --text-muted: #94a3b8;
    --text-dim:   #475569;

    
    --nuc-a: #22d3ee;   
    --nuc-u: #fb7185;   
    --nuc-g: #4ade80;   
    --nuc-c: #fbbf24;   

    
    --pair-au: #38bdf8;
    --pair-gc: #f87171;
    --pair-gu: #34d399;

    
    --accent:       #818cf8;
    --accent-dim:   #6366f1;
    --accent-glow:  rgba(129, 140, 248, .18);
    --accent-text:  #c7d2fe;

    
    --cell-highlight: #fbbf24;
    --cell-dep:       rgba(56, 189, 248, .45);
    --cell-traceback: rgba(192, 132, 252, .5);

    
    --error:   #f87171;
    --warning: #fbbf24;

    
    --r:    6px;
    --r-md: 10px;
    --r-lg: 16px;

    
    --shadow:    0 2px 8px rgba(0,0,0,.35);
    --shadow-lg: 0 8px 32px rgba(0,0,0,.5);

    
    --font-display: 'Playfair Display', Georgia, serif;
    --font-body:    'Outfit', system-ui, sans-serif;
    --font-mono:    'DM Mono', 'Courier New', monospace;
}

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

html { scroll-behavior: smooth; }

body {
    font-family: var(--font-body);
    background: var(--bg-deep);
    color: var(--text);
    min-height: 100vh;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

.hidden { display: none !important; }

.grain {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 9999;
    opacity: .035;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
    background-repeat: repeat;
    background-size: 200px;
}

#input-screen {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
    background:
        radial-gradient(ellipse 60% 50% at 50% 45%, rgba(99,102,241,.07) 0%, transparent 70%),
        radial-gradient(ellipse 40% 30% at 70% 20%, rgba(34,211,238,.04) 0%, transparent 60%),
        var(--bg-deep);
}

.input-card {
    position: relative;
    background: var(--bg-panel);
    border: 1px solid var(--border);
    border-radius: var(--r-lg);
    box-shadow: var(--shadow-lg);
    padding: 2.75rem 3rem 2.5rem;
    max-width: 620px;
    width: 100%;
    backdrop-filter: blur(20px);
}

.card-glow {
    position: absolute;
    inset: -1px;
    border-radius: var(--r-lg);
    background: linear-gradient(135deg, rgba(129,140,248,.12), transparent 40%, transparent 60%, rgba(34,211,238,.08));
    pointer-events: none;
    z-index: 0;
}

.input-card > * { position: relative; z-index: 1; }

.title-block { margin-bottom: 2rem; }

.eyebrow {
    font-size: .7rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: .14em;
    color: var(--accent);
    margin-bottom: .35rem;
}

.input-card h1 {
    font-family: var(--font-display);
    font-size: 2.8rem;
    font-weight: 900;
    letter-spacing: -.02em;
    line-height: 1;
    background: linear-gradient(135deg, #e2e8f0 30%, var(--accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: .25rem;
}

.subtitle {
    font-size: .95rem;
    font-weight: 300;
    color: var(--text-muted);
    letter-spacing: .01em;
}

.field { margin-bottom: 1.4rem; }

.field > label {
    display: block;
    font-size: .68rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: .1em;
    color: var(--text-dim);
    margin-bottom: .5rem;
}

.field-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: .5rem;
}

.field-header label {
    font-size: .68rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: .1em;
    color: var(--text-dim);
}

.format-toggle {
    display: flex;
    border: 1px solid var(--border);
    border-radius: var(--r);
    overflow: hidden;
    background: var(--bg-surface);
}

.format-btn {
    padding: .3rem .7rem;
    border: none;
    background: transparent;
    font-family: var(--font-body);
    font-size: .72rem;
    font-weight: 500;
    color: var(--text-dim);
    cursor: pointer;
    transition: all .2s;
}
.format-btn + .format-btn { border-left: 1px solid var(--border); }

.format-btn.active {
    background: var(--accent-dim);
    color: #fff;
}

.seq-input-plain,
.seq-input-fasta {
    width: 100%;
    padding: .7rem .9rem;
    border: 1.5px solid var(--border);
    border-radius: var(--r-md);
    background: var(--bg-surface);
    font-family: var(--font-mono);
    font-size: 1.05rem;
    font-weight: 500;
    color: var(--text);
    letter-spacing: .12em;
    transition: border-color .25s, box-shadow .25s;
}

.seq-input-fasta {
    font-size: .92rem;
    letter-spacing: .06em;
    resize: vertical;
}

.seq-input-plain:focus,
.seq-input-fasta:focus {
    outline: none;
    border-color: var(--border-focus);
    box-shadow: 0 0 0 3px var(--accent-glow), 0 0 20px rgba(129,140,248,.08);
}

.seq-input-plain.invalid,
.seq-input-fasta.invalid { border-color: var(--error); }

.seq-input-plain::placeholder,
.seq-input-fasta::placeholder {
    color: var(--text-dim);
    font-weight: 400;
}

#seq-messages { min-height: 1.1rem; margin-top: .3rem; }
.msg { font-size: .78rem; display: block; }
.msg-error { color: var(--error); }
.msg-warning { color: var(--warning); }

.chip-row {
    display: flex;
    flex-wrap: wrap;
    gap: .45rem;
}

.chip {
    padding: .4rem .9rem;
    border: 1px solid var(--border);
    border-radius: 999px;
    background: var(--bg-surface);
    font-size: .78rem;
    font-family: var(--font-mono);
    font-weight: 400;
    color: var(--text-muted);
    cursor: pointer;
    transition: all .2s;
    user-select: none;
}

.chip:hover {
    border-color: var(--accent-dim);
    background: var(--bg-raised);
    color: var(--text);
    box-shadow: 0 0 12px var(--accent-glow);
}

.chip.selected {
    border-color: var(--accent);
    background: rgba(129, 140, 248, .12);
    color: var(--accent-text);
    font-weight: 500;
    box-shadow: 0 0 16px var(--accent-glow);
}

.chip .chip-name {
    font-family: var(--font-body);
    font-size: .68rem;
    font-weight: 500;
    color: var(--text-dim);
    margin-right: .4rem;
    text-transform: uppercase;
    letter-spacing: .04em;
}

.params-row {
    display: flex;
    align-items: center;
    gap: 2rem;
    margin-bottom: 1.5rem;
}

.params-row .field { margin-bottom: 0; }
.params-row .field > label { margin-bottom: .4rem; }

.checkbox-field label {
    display: flex;
    align-items: center;
    gap: .5rem;
    cursor: pointer;
    font-size: .85rem;
    font-weight: 400;
    color: var(--text-muted);
}

.checkbox-field input[type="checkbox"] {
    position: absolute;
    opacity: 0;
    width: 0;
    height: 0;
}

.check-box {
    display: inline-block;
    width: 18px;
    height: 18px;
    border: 1.5px solid var(--border);
    border-radius: 4px;
    background: var(--bg-surface);
    transition: all .2s;
    position: relative;
    flex-shrink: 0;
}

.checkbox-field input:checked + .check-box {
    background: var(--accent-dim);
    border-color: var(--accent);
}

.checkbox-field input:checked + .check-box::after {
    content: '';
    position: absolute;
    top: 2px;
    left: 5px;
    width: 5px;
    height: 9px;
    border: 2px solid #fff;
    border-top: none;
    border-left: none;
    transform: rotate(45deg);
}

/* ── Macierz energii par (ekran startowy) ───────────────────────────── */
.energy-field {
    margin-bottom: 1.5rem;
}

.energy-hint {
    margin-left: .5rem;
    font-size: .7rem;
    font-weight: 400;
    color: var(--text-dim);
    text-transform: none;
    letter-spacing: 0;
}

.energy-matrix {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 4px;
    max-width: 280px;
    font-family: var(--font-mono);
}

.em-cell {
    display: flex;
    align-items: center;
    justify-content: center;
    aspect-ratio: 1;
    border-radius: var(--r);
    font-size: .85rem;
    user-select: none;
}

.em-corner {
    color: var(--text-dim);
    font-style: italic;
}

.em-header {
    font-weight: 600;
    color: var(--text-muted);
}

.em-nuc-A { color: var(--nuc-a); }
.em-nuc-U { color: var(--nuc-u); }
.em-nuc-G { color: var(--nuc-g); }
.em-nuc-C { color: var(--nuc-c); }

.em-value {
    background: var(--bg-surface);
    border: 1px solid var(--border);
    color: var(--text-dim);
    transition: background .2s, color .2s, border-color .2s;
}

.em-value.em-pos {
    background: var(--accent-glow);
    border-color: var(--border-focus);
    color: var(--accent-text);
    font-weight: 500;
}

.em-value.em-wobble {
    border-color: var(--pair-gu);
}

.em-value.em-wobble.em-pos {
    background: rgba(52, 211, 153, .18);
    color: var(--pair-gu);
}

input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    width: 140px;
    height: 4px;
    background: var(--bg-raised);
    border-radius: 2px;
    outline: none;
    cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--accent);
    border: 2px solid var(--bg-panel);
    box-shadow: 0 0 8px var(--accent-glow);
    cursor: pointer;
    transition: transform .15s;
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

input[type="range"]::-moz-range-thumb {
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--accent);
    border: 2px solid var(--bg-panel);
    box-shadow: 0 0 8px var(--accent-glow);
    cursor: pointer;
}

.action-row {
    display: flex;
    align-items: flex-end;
    gap: 1.25rem;
}

.mode-selector {
    display: flex;
    gap: .6rem;
    flex: 1;
}

.mode-btn {
    flex: 1;
    display: flex;
    align-items: center;
    gap: .7rem;
    padding: .7rem .9rem;
    border: 1.5px solid var(--border);
    border-radius: var(--r-md);
    background: var(--bg-surface);
    cursor: pointer;
    transition: all .2s;
}

.mode-btn:hover {
    border-color: rgba(129,140,248,.3);
    background: var(--bg-raised);
}

.mode-btn.active {
    border-color: var(--accent);
    background: rgba(129,140,248,.08);
    box-shadow: 0 0 20px var(--accent-glow);
}

.mode-indicator {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    border: 2px solid var(--text-dim);
    flex-shrink: 0;
    transition: all .2s;
}

.mode-btn.active .mode-indicator {
    border-color: var(--accent);
    background: var(--accent);
    box-shadow: 0 0 6px var(--accent);
}

.mode-text { display: flex; flex-direction: column; }
.mode-label { font-size: .82rem; font-weight: 600; color: var(--text); }
.mode-desc  { font-size: .68rem; color: var(--text-dim); margin-top: .05rem; }

#btn-compute {
    display: flex;
    align-items: center;
    gap: .5rem;
    padding: .8rem 1.8rem;
    background: var(--accent-dim);
    color: #fff;
    border: none;
    border-radius: var(--r-md);
    font-family: var(--font-body);
    font-size: .95rem;
    font-weight: 600;
    letter-spacing: .02em;
    cursor: pointer;
    transition: all .25s;
    white-space: nowrap;
    box-shadow: 0 4px 16px rgba(99,102,241,.25);
}

#btn-compute:hover:not(:disabled) {
    background: var(--accent);
    box-shadow: 0 4px 24px rgba(99,102,241,.35);
    transform: translateY(-1px);
}

#btn-compute:active:not(:disabled) { transform: translateY(0); }

#btn-compute:disabled {
    opacity: .3;
    cursor: not-allowed;
    box-shadow: none;
}

#results-screen {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    background:
        radial-gradient(ellipse 50% 30% at 30% 15%, rgba(99,102,241,.05) 0%, transparent 70%),
        var(--bg-deep);
}

#results-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: .6rem 1.5rem;
    background: var(--bg-panel);
    border-bottom: 1px solid var(--border);
}

#btn-back {
    display: flex;
    align-items: center;
    gap: .35rem;
    padding: .35rem .75rem;
    border: 1px solid var(--border);
    border-radius: var(--r);
    background: transparent;
    font-family: var(--font-body);
    font-size: .8rem;
    color: var(--text-muted);
    cursor: pointer;
    transition: all .15s;
}
#btn-back:hover {
    border-color: var(--accent-dim);
    color: var(--text);
    background: var(--bg-surface);
}

.result-seq-label {
    font-family: var(--font-mono);
    font-size: .82rem;
    color: var(--text-dim);
    letter-spacing: .08em;
}

#edu-controls {
    background: var(--bg-panel);
    border-bottom: 1px solid var(--border);
    padding: .6rem 1.5rem;
}

.edu-controls-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    flex-wrap: wrap;
}

.edu-buttons {
    display: flex;
    gap: .35rem;
}

.edu-buttons button {
    display: flex;
    align-items: center;
    gap: .3rem;
    padding: .3rem .6rem;
    border: 1px solid var(--border);
    border-radius: var(--r);
    background: var(--bg-surface);
    font-family: var(--font-body);
    font-size: .76rem;
    font-weight: 500;
    color: var(--text-muted);
    cursor: pointer;
    transition: all .15s;
}

.edu-buttons button:hover:not(:disabled) {
    border-color: var(--accent-dim);
    color: var(--text);
    background: var(--bg-raised);
}

.edu-buttons button:disabled {
    opacity: .25;
    cursor: not-allowed;
}

.edu-buttons .btn-accent {
    background: var(--accent-dim);
    border-color: var(--accent-dim);
    color: #fff;
}

.edu-buttons .btn-accent:hover:not(:disabled) {
    background: var(--accent);
    border-color: var(--accent);
}

.edu-info {
    display: flex;
    align-items: center;
    gap: .6rem;
}

.edu-info label {
    font-size: .7rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: .06em;
    color: var(--text-dim);
}

#speed-slider { width: 90px; }

.step-label {
    font-family: var(--font-mono);
    font-size: .78rem;
    font-weight: 500;
    color: var(--accent);
    min-width: 100px;
    text-align: right;
}

.step-desc {
    font-size: .82rem;
    font-weight: 300;
    color: var(--text-muted);
    min-height: 1.2rem;
    margin-top: .3rem;
    font-family: var(--font-mono);
    font-size: .75rem;
}

#viz-panel {
    flex: 1;
    display: flex;
    gap: .75rem;
    padding: .75rem 1.5rem;
    overflow: auto;
}

.viz-box {
    flex: 1;
    background: var(--bg-panel);
    border-radius: var(--r-lg);
    border: 1px solid var(--border);
    padding: 1rem;
    display: flex;
    flex-direction: column;
    min-width: 0;
    box-shadow: var(--shadow);
}

.viz-box h2 {
    font-family: var(--font-body);
    font-size: .72rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: .1em;
    margin-bottom: .6rem;
    color: var(--text-dim);
}

#matrix-svg-wrap, #arc-svg-wrap {
    flex: 1;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 0;
}

#matrix-svg, #arc-svg { display: block; }

#dot-bracket {
    font-family: var(--font-mono);
    font-size: .85rem;
    text-align: center;
    margin-top: .5rem;
    color: var(--accent);
    letter-spacing: .14em;
    min-height: 1.2rem;
    opacity: .8;
}

.cell-rect {
    stroke: rgba(148, 163, 184, .08);
    stroke-width: .5;
    transition: fill .2s, stroke .15s;
    cursor: pointer;
}

.cell-rect.highlight-current {
    stroke: var(--cell-highlight);
    stroke-width: 2.5;
    filter: drop-shadow(0 0 4px rgba(251,191,36,.3));
}

.cell-rect.highlight-dep {
    stroke: var(--pair-au);
    stroke-width: 2;
    filter: drop-shadow(0 0 3px rgba(56,189,248,.3));
}

.cell-rect.highlight-trace {
    stroke: rgba(192,132,252,.7);
    stroke-width: 2;
    filter: drop-shadow(0 0 3px rgba(192,132,252,.3));
}

.cell-rect.hover-dep {
    fill: var(--cell-dep) !important;
}

.cell-text {
    font-family: var(--font-mono);
    font-size: 11px;
    text-anchor: middle;
    dominant-baseline: central;
    pointer-events: none;
    user-select: none;
    fill: var(--text);
}

.header-text {
    font-family: var(--font-mono);
    font-size: 11px;
    font-weight: 500;
    text-anchor: middle;
    dominant-baseline: central;
    fill: var(--text-muted);
}

.arc-path {
    fill: none;
    stroke-width: 2;
    opacity: 0;
    transition: opacity .5s ease, stroke-width .2s;
    cursor: pointer;
    filter: drop-shadow(0 0 4px currentColor);
}

.arc-path.visible { opacity: .85; }

.arc-path.hover-highlight {
    stroke-width: 3.5;
    opacity: 1;
    filter: drop-shadow(0 0 8px currentColor);
}

.arc-path.arc-selected {
    stroke-width: 3.5;
    opacity: 1;
    filter: drop-shadow(0 0 10px currentColor);
}

.nuc-text {
    font-family: var(--font-mono);
    font-size: 14px;
    font-weight: 500;
    text-anchor: middle;
    dominant-baseline: central;
}

.overlay {
    position: fixed;
    inset: 0;
    background: rgba(8,12,22,.7);
    backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
}

.overlay.hidden { display: none; }

.overlay-content {
    background: var(--bg-panel);
    border: 1px solid var(--border);
    border-radius: var(--r-lg);
    padding: 1.75rem;
    max-width: 480px;
    width: 90%;
    box-shadow: 0 16px 48px rgba(0,0,0,.5);
    position: relative;
}

.overlay-close {
    position: absolute;
    top: .65rem;
    right: .85rem;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-dim);
    transition: color .15s;
}

.overlay-close:hover { color: var(--text); }

.overlay-content h3 {
    font-family: var(--font-body);
    font-weight: 600;
    font-size: 1rem;
    margin-bottom: .85rem;
    color: var(--text);
}

#cell-detail-body {
    font-size: .88rem;
    line-height: 1.6;
    color: var(--text-muted);
    font-family: var(--font-mono);
    font-size: .8rem;
}

#cell-detail-body strong { color: var(--accent); }

#right-panel {
    display: flex;
    flex-direction: column;
}

.tab-bar {
    display: flex;
    gap: 3px;
    padding: 4px;
    margin: -1rem -1rem .75rem;
    background: var(--bg-surface);
    border-bottom: 1px solid var(--border);
    border-radius: var(--r-lg) var(--r-lg) 0 0;
    flex-shrink: 0;
}

.tab-btn {
    flex: 1;
    padding: .32rem .5rem;
    border: none;
    background: transparent;
    font-family: var(--font-body);
    font-size: .68rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: .06em;
    color: var(--text-dim);
    cursor: pointer;
    border-radius: var(--r);
    transition: all .15s;
}

.tab-btn:hover { color: var(--text); background: var(--bg-raised); }
.tab-btn.active { background: var(--accent-dim); color: #fff; }

.tab-panel {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-height: 0;
}

#tree-container {
    flex: 1;
    overflow: auto;
    padding: 6px 4px;
    min-height: 0;
}

.tree-empty {
    color: var(--text-dim);
    font-size: .82rem;
    text-align: center;
    margin-top: 2rem;
}

.tree-node {
    stroke-width: 1.2;
    transition: fill .15s, stroke .15s, stroke-width .1s;
}

.tree-node-base        { fill: rgba(71, 85, 105, .18); stroke: rgba(71,85,105,.35); }
.tree-node-skip_i      { fill: rgba(56, 189, 248, .13); stroke: rgba(56,189,248,.4); }
.tree-node-skip_j      { fill: rgba(56, 189, 248, .08); stroke: rgba(56,189,248,.28); }
.tree-node-pair        { fill: rgba(74, 222, 128, .14); stroke: rgba(74,222,128,.42); }
.tree-node-bifurcation { fill: rgba(129,140,248, .18); stroke: rgba(129,140,248,.55); }

.tree-node-hover  { fill: var(--bg-glass) !important; stroke: var(--accent) !important; stroke-width: 2 !important; }
.tree-node-active { stroke: var(--cell-highlight) !important; stroke-width: 2.2 !important; }

.tree-text-main {
    font-family: var(--font-mono);
    font-size: 10px;
    text-anchor: middle;
    dominant-baseline: middle;
    fill: var(--text);
    pointer-events: none;
    user-select: none;
}

.tree-text-sub {
    font-family: var(--font-mono);
    font-size: 9px;
    text-anchor: middle;
    dominant-baseline: middle;
    fill: var(--text-dim);
    pointer-events: none;
    user-select: none;
}

.tree-edge-label {
    font-family: var(--font-mono);
    font-size: 8px;
    text-anchor: middle;
    dominant-baseline: middle;
    fill: var(--text-dim);
    pointer-events: none;
    user-select: none;
    opacity: .65;
}

#helix-canvas-wrap {
    flex: 1;
    min-height: 0;
    position: relative;
    border-radius: var(--r);
    overflow: hidden;
}

#helix-canvas-wrap canvas {
    display: block;
}

.viz-legend {
    display: flex;
    align-items: center;
    gap: .35rem;
    padding: .4rem .2rem 0;
    flex-wrap: wrap;
    flex-shrink: 0;
}

.leg-item {
    padding: .14rem .38rem;
    border-radius: 4px;
    font-family: var(--font-mono);
    font-size: .67rem;
    font-weight: 500;
    white-space: nowrap;
}

.leg-sep { color: var(--text-dim); font-size: .75rem; margin: 0 .1rem; }

.leg-item.leg-base        { background: rgba(71,85,105,.2);   color: #94a3b8; }
.leg-item.leg-skip_i      { background: rgba(56,189,248,.15); color: #38bdf8; }
.leg-item.leg-skip_j      { background: rgba(56,189,248,.1);  color: #7dd3fc; }
.leg-item.leg-pair        { background: rgba(74,222,128,.15); color: #4ade80; }
.leg-item.leg-bifurcation { background: rgba(129,140,248,.18);color: #818cf8; }

.helix-hint {
    font-size: .65rem;
    color: var(--text-dim);
    margin-left: auto;
    font-family: var(--font-body);
    white-space: nowrap;
}

/* --- Statistics tab --- */

.stats-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: .75rem;
    padding: .5rem .25rem;
    flex: 1;
    align-content: start;
}

.stat-card {
    background: var(--bg-surface);
    border: 1px solid var(--border);
    border-radius: var(--r-md);
    padding: .9rem 1rem;
    display: flex;
    flex-direction: column;
    gap: .3rem;
}

.stat-card-wide {
    grid-column: 1 / -1;
}

.stat-label {
    font-size: .68rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: .1em;
    color: var(--text-dim);
}

.stat-value {
    font-family: var(--font-mono);
    font-size: 1.5rem;
    font-weight: 500;
    color: var(--accent);
}

.pair-dist {
    display: flex;
    flex-direction: column;
    gap: .5rem;
    margin-top: .35rem;
}

.pair-dist-row {
    display: flex;
    align-items: center;
    gap: .6rem;
}

.pair-type {
    font-family: var(--font-mono);
    font-size: .78rem;
    font-weight: 500;
    min-width: 2.5rem;
}

.pair-type-au { color: var(--pair-au); }
.pair-type-gc { color: var(--pair-gc); }
.pair-type-gu { color: var(--pair-gu); }

.pair-bar-track {
    flex: 1;
    height: 8px;
    background: var(--bg-raised);
    border-radius: 4px;
    overflow: hidden;
}

.pair-bar {
    height: 100%;
    border-radius: 4px;
    transition: width .4s ease;
    width: 0;
}

#bar-au { background: var(--pair-au); }
#bar-gc { background: var(--pair-gc); }
#bar-gu { background: var(--pair-gu); }

.pair-count {
    font-family: var(--font-mono);
    font-size: .82rem;
    font-weight: 500;
    color: var(--text-muted);
    min-width: 1.5rem;
    text-align: right;
}

/* --- Algorithm info modal --- */

.overlay-content-wide {
    max-width: 640px;
    max-height: 85vh;
    overflow-y: auto;
}

.btn-info {
    display: flex;
    align-items: center;
    gap: .35rem;
    padding: .35rem .75rem;
    border: 1px solid var(--border);
    border-radius: var(--r);
    background: transparent;
    font-family: var(--font-body);
    font-size: .8rem;
    color: var(--text-muted);
    cursor: pointer;
    transition: all .15s;
    margin-left: auto;
}

.btn-info:hover {
    border-color: var(--accent-dim);
    color: var(--text);
    background: var(--bg-surface);
}

.algo-info-body {
    font-size: .88rem;
    line-height: 1.65;
    color: var(--text-muted);
}

.algo-section {
    margin-bottom: 1.25rem;
}

.algo-section:last-child {
    margin-bottom: 0;
}

.algo-section h4 {
    font-family: var(--font-body);
    font-weight: 600;
    font-size: .82rem;
    text-transform: uppercase;
    letter-spacing: .06em;
    color: var(--accent);
    margin-bottom: .5rem;
}

.algo-section p {
    margin-bottom: .5rem;
}

.algo-formula {
    font-family: var(--font-mono);
    font-size: .82rem;
    background: var(--bg-surface);
    border: 1px solid var(--border);
    border-radius: var(--r);
    padding: .75rem 1rem;
    line-height: 1.8;
    color: var(--text);
}

.algo-comment {
    color: var(--text-dim);
    margin-left: 1rem;
    font-size: .75rem;
}

.algo-note {
    font-size: .78rem;
    color: var(--text-dim);
    font-style: italic;
    margin-top: .35rem;
}

.algo-code {
    font-family: var(--font-mono);
    font-size: .78rem;
    background: var(--bg-surface);
    border: 1px solid var(--border);
    border-radius: var(--r);
    padding: .75rem 1rem;
    line-height: 1.7;
    color: var(--text);
    overflow-x: auto;
    white-space: pre;
}

.complexity-grid {
    display: flex;
    gap: .75rem;
    margin-bottom: .5rem;
}

.complexity-item {
    flex: 1;
    background: var(--bg-surface);
    border: 1px solid var(--border);
    border-radius: var(--r);
    padding: .6rem .8rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: .2rem;
}

.complexity-label {
    font-size: .68rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: .08em;
    color: var(--text-dim);
}

.complexity-value {
    font-family: var(--font-mono);
    font-size: 1.2rem;
    font-weight: 500;
    color: var(--accent);
}

::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--bg-raised); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-dim); }

@media (max-width: 900px) {
    #viz-panel { flex-direction: column; }
    .input-card { padding: 1.75rem; }
    .action-row { flex-direction: column; align-items: stretch; }
    .mode-selector { flex-direction: column; }
    .params-row { flex-direction: column; align-items: flex-start; gap: 1rem; }
    .edu-controls-inner { flex-direction: column; align-items: flex-start; }
}

@media (max-width: 500px) {
    #input-screen { padding: 1rem; }
    .input-card { padding: 1.25rem 1rem; }
    .input-card h1 { font-size: 2rem; }
    .edu-buttons { flex-wrap: wrap; }
}

@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(12px); }
    to   { opacity: 1; transform: translateY(0); }
}

.input-card {
    animation: fadeInUp .5s ease-out;
}

.input-card .field,
.input-card .params-row,
.input-card .action-row {
    animation: fadeInUp .4s ease-out both;
}

.input-card .title-block  { animation-delay: .05s; }
.input-card .field:nth-child(2) { animation-delay: .1s; }
.input-card .field:nth-child(3) { animation-delay: .15s; }
.input-card .params-row   { animation-delay: .2s; }
.input-card .action-row   { animation-delay: .25s; }

#results-screen .viz-box {
    animation: fadeInUp .4s ease-out both;
}

#results-screen #matrix-container { animation-delay: .1s; }
#results-screen #right-panel      { animation-delay: .2s; }