* {
    box-sizing: border-box;
}


.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
}

h1 {
    margin-bottom: 40px;
    text-align: center;
}

.input-section {
    max-width: 700px;
    margin: 0 auto 50px;
}

.input-section label {
    display: block;
    margin-bottom: 10px;
    font-weight: bold;
}

.input-row {
    display: flex;
    gap: 10px;
}

input {
    flex: 1;
    padding: 12px;
    border: 1px solid #aaa;
    border-radius: 6px;
    font-size: 16px;
}

button {
    padding: 12px 22px;
    border: none;
    border-radius: 6px;
    background: #333;
    color: white;
    font-size: 16px;
    cursor: pointer;
}

button:hover {
    background: #555;
}

.system {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
}

.system-block {
    width: 220px;
    min-height: 150px;

    padding: 20px;

    background: white;
    border: 2px solid #333;
    border-radius: 10px;

    text-align: center;
}

.system-block h2 {
    margin-top: 0;
    font-size: 20px;
}

.message {
    min-height: 50px;

    display: flex;
    align-items: center;
    justify-content: center;

    padding: 10px;

    background: #f5f5f5;
    border-radius: 6px;

    overflow-wrap: anywhere;
}

.arrow {
    font-size: 32px;
    font-weight: bold;
}

.error {
    margin-top: 30px;
    text-align: center;
    color: #b00020;
}

@media (max-width: 900px) {
    .system {
        flex-direction: column;
    }

    .arrow {
        transform: rotate(90deg);
    }

    .input-row {
        flex-direction: column;
    }
}

/* --- Overlay / выбор алгоритма --- */

.overlay {
    position: fixed;
    inset: 0;

    display: flex;

    padding: 20px;

    /* Если модалка не помещается по высоте — overlay прокручивается колёсиком */
    overflow-y: auto;
    overscroll-behavior: contain;

    background: rgba(0, 0, 0, 0.55);
    z-index: 100;
}

.overlay[hidden] {
    display: none;
}

.modal {
    width: 100%;
    max-width: 560px;

    padding: 30px;

    background: white;
    border-radius: 14px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

.modal {
    position: relative;

    /* Центрирование через auto-отступы: при переполнении верх модалки не обрезается */
    margin: auto;
}

.modal h2 {
    margin: 0 0 8px;
    text-align: center;
}

.modal-close {
    position: absolute;
    top: 14px;
    right: 14px;

    width: 30px;
    height: 30px;

    background: transparent;
    border: none;
    border-radius: 50%;

    color: #666;
    font-size: 22px;
    line-height: 1;
    cursor: pointer;
}

.modal-close:hover {
    background: #eee;
    color: #222;
}

.modal-hint {
    margin: 0 0 24px;
    text-align: center;
    color: #666;
    font-size: 14px;
}

.algorithm-options {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.algorithm-option {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 4px;

    padding: 16px 18px;

    background: #f7f7f7;
    border: 2px solid #ddd;
    border-radius: 10px;

    text-align: left;
    cursor: pointer;

    transition: border-color 0.15s ease, background 0.15s ease;
}

.algorithm-option:hover {
    border-color: #333;
    background: #efefef;
}

.algorithm-title {
    font-size: 17px;
    font-weight: bold;
    color: #222;
}

.algorithm-desc {
    font-size: 13px;
    color: #666;
}

/* --- Заголовок + смена алгоритма --- */

.title-row {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: center;
    gap: 14px;

    margin-bottom: 40px;
}

.title-row h1 {
    margin: 0;
}

.ghost-button {
    padding: 8px 14px;

    background: transparent;
    border: 1px solid #999;
    border-radius: 20px;

    color: #333;
    font-size: 13px;
}

.ghost-button:hover {
    background: #e8e8e8;
}

.ghost-button[hidden] {
    display: none;
}

/* --- Визуализация Хаффмана --- */

.code-section {
    max-width: 900px;
    margin: 50px auto 0;
}

.code-section[hidden] {
    display: none;
}

.code-section h2 {
    text-align: center;
    margin-bottom: 24px;
}

.code-block {
    margin-bottom: 34px;
}

.code-block h3 {
    margin-bottom: 12px;
    font-size: 16px;
}

.table-wrap {
    overflow-x: auto;
}

.code-table {
    width: 100%;
    border-collapse: collapse;
    background: white;
    border-radius: 8px;
    overflow: hidden;
}

.code-table th,
.code-table td {
    padding: 8px 12px;
    border: 1px solid #ddd;
    text-align: center;
}

.code-table th {
    background: #333;
    color: white;
}

.code-table td.char-cell {
    font-family: "Courier New", monospace;
    font-weight: bold;
}

.code-table td.code-cell {
    font-family: "Courier New", monospace;
    letter-spacing: 1px;
    color: #0a6b2e;
}

.trace-row {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.trace-chip {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;

    min-width: 52px;

    padding: 8px 10px;

    background: white;
    border: 2px solid #333;
    border-radius: 8px;

    font-family: "Courier New", monospace;

    animation: chip-in 0.25s ease both;
}

.trace-chip .chip-top {
    font-size: 16px;
    font-weight: bold;
}

.trace-chip .chip-bottom {
    font-size: 12px;
    color: #0a6b2e;
    letter-spacing: 1px;
}

.trace-chip.decode-chip .chip-top {
    color: #0a6b2e;
}

.trace-chip.decode-chip .chip-bottom {
    color: #222;
    font-size: 16px;
    font-weight: bold;
}

.trace-arrow {
    align-self: center;
    color: #999;
}

.bitstring {
    margin-top: 14px;

    padding: 10px 14px;

    background: white;
    border-radius: 8px;

    font-family: "Courier New", monospace;
    letter-spacing: 2px;
    word-break: break-all;
}

@keyframes chip-in {
    from {
        opacity: 0;
        transform: translateY(6px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* --- Дерево Хаффмана --- */

.tree-wrap {
    display: flex;
    justify-content: center;

    padding: 20px;
    overflow-x: auto;

    background: white;
    border-radius: 8px;
}

.code-tree-svg {
    max-width: 100%;
}

.tree-edge {
    stroke: #999;
    stroke-width: 2;
}

.tree-edge-label {
    font-family: "Courier New", monospace;
    font-size: 12px;
    font-weight: bold;
    fill: #0a6b2e;
}

.tree-node-circle {
    fill: white;
    stroke: #333;
    stroke-width: 2;
}

.tree-node-circle.tree-leaf-circle {
    stroke: #0a6b2e;
    stroke-width: 2.5;
}

.tree-char {
    font-family: Arial, sans-serif;
    font-size: 13px;
    font-weight: bold;
    fill: #222;
}

.tree-freq {
    font-family: Arial, sans-serif;
    font-size: 10px;
    fill: #666;
}

/* --- Выбор источника частот --- */

.frequency-source-row {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: center;
    gap: 12px;

    margin-bottom: 30px;
}

.frequency-source-row[hidden] {
    display: none;
}

.frequency-source-label {
    font-size: 14px;
    color: #555;
}

.segmented-control {
    display: inline-flex;
    border: 1px solid #999;
    border-radius: 20px;
    overflow: hidden;
}

.segmented-option {
    padding: 6px 14px;

    background: white;
    border: none;

    color: #333;
    font-size: 13px;
    cursor: pointer;

    transition: background 0.15s ease, color 0.15s ease;
}

.segmented-option + .segmented-option {
    border-left: 1px solid #999;
}

.segmented-option:hover {
    background: #eee;
}

.segmented-option.active {
    background: #333;
    color: white;
}

.note {
    margin: -4px 0 14px;

    font-size: 13px;
    color: #a15b00;
}

.note[hidden] {
    display: none;
}

/* --- Выбор варианта кода Хэмминга --- */

.hamming-variant-row {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: center;
    gap: 12px;

    margin-bottom: 20px;
}

.hamming-variant-row[hidden] {
    display: none;
}

/* --- Симуляция ошибки для Хэмминга --- */

.hamming-error-row {
    display: flex;
    justify-content: center;

    margin-bottom: 30px;
}

.hamming-error-row[hidden] {
    display: none;
}

.checkbox-row {
    display: flex;
    align-items: center;
    gap: 8px;

    font-size: 14px;
    color: #333;
    cursor: pointer;
}

.checkbox-row input {
    width: 16px;
    height: 16px;
    cursor: pointer;
}

/* --- Визуализация Хэмминга --- */

.hamming-section {
    max-width: 900px;
    margin: 50px auto 0;
}

.hamming-section[hidden] {
    display: none;
}

.hamming-section h2 {
    text-align: center;
    margin-bottom: 24px;
}

.hamming-legend {
    display: flex;
    flex-wrap: wrap;
    gap: 18px;

    margin: 0 0 12px;

    font-size: 12px;
    color: #666;
}

.legend-swatch {
    display: inline-block;
    width: 10px;
    height: 10px;
    margin-right: 4px;

    border-radius: 2px;
    vertical-align: middle;
}

.legend-data {
    background: white;
    border: 2px solid #0a6b2e;
}

.legend-parity {
    background: white;
    border: 2px solid #a15b00;
}

.legend-ok {
    background: #e6f4ea;
    border: 2px solid #0a6b2e;
}

.legend-error {
    background: #fdecea;
    border: 2px solid #c0392b;
}

.hamming-blocks {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
}

.hamming-block-card {
    padding: 10px 12px;

    background: white;
    border: 2px solid #ddd;
    border-radius: 10px;

    animation: chip-in 0.25s ease both;
}

.hamming-block-card.has-error {
    border-color: #c0392b;
    background: #fdecea;
}

.hamming-block-label {
    margin-bottom: 6px;

    font-size: 11px;
    color: #666;
    text-align: center;
}

.hamming-bit-row {
    display: flex;
    gap: 3px;
}

.hamming-bit {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2px;

    width: 22px;
}

.hamming-bit-value {
    display: flex;
    align-items: center;
    justify-content: center;

    width: 22px;
    height: 22px;

    background: white;
    border: 2px solid #0a6b2e;
    border-radius: 4px;

    font-family: "Courier New", monospace;
    font-size: 13px;
    font-weight: bold;
}

.hamming-bit.is-parity .hamming-bit-value {
    border-color: #a15b00;
}

.hamming-bit.is-flipped .hamming-bit-value {
    border-color: #c0392b;
    background: #fdecea;
    color: #c0392b;
}

.hamming-bit-position {
    font-size: 9px;
    color: #999;
}

.hamming-block-footer {
    margin-top: 6px;

    font-size: 11px;
    color: #444;
    text-align: center;
}

.hamming-block-footer .error-text {
    color: #c0392b;
    font-weight: bold;
}

.hamming-block-footer .ok-text {
    color: #0a6b2e;
}

.hamming-transmission {
    display: flex;
    flex-direction: column;
    gap: 10px;

    padding: 14px;

    background: white;
    border-radius: 8px;
}

.hamming-transmission-row {
    display: flex;
    align-items: center;
    gap: 10px;

    font-family: "Courier New", monospace;
    font-size: 13px;
    letter-spacing: 1px;
    word-break: break-all;
}

.hamming-transmission-row .transmission-label {
    flex-shrink: 0;

    width: 90px;

    font-family: Arial, sans-serif;
    font-size: 12px;
    color: #666;
}

.hamming-transmission-row .flipped-bit {
    color: #c0392b;
    font-weight: bold;
    text-decoration: underline;
}

/* --- Карточки блоков Хэмминга с ошибкой: кликабельны --- */

.hamming-block-card.has-error.clickable {
    cursor: pointer;
    transition: transform 0.1s ease, box-shadow 0.15s ease;
}

.hamming-block-card.has-error.clickable:hover,
.hamming-block-card.has-error.clickable:focus-visible {
    transform: translateY(-2px);
    box-shadow: 0 4px 14px rgba(192, 57, 43, 0.25);
    outline: none;
}

.detail-hint {
    display: block;
    margin-top: 2px;

    color: #888;
    font-size: 10px;
    font-style: italic;
}

/* --- Модалка с подробностями ошибки --- */

.hamming-detail-modal {
    max-width: 640px;
    max-height: 85vh;
    overflow-y: auto;
}

.hamming-detail-section {
    margin-bottom: 20px;
}

.hamming-detail-section h4 {
    margin: 0 0 8px;
    font-size: 14px;
    color: #333;
}

.hamming-detail-section p {
    margin: 8px 0 0;
    font-size: 13px;
    line-height: 1.5;
    color: #333;
}

.hamming-detail-bit-row {
    margin-bottom: 4px;
}

.hamming-bit.is-covered .hamming-bit-value {
    background: #fff3e0;
}

.hamming-check-row {
    padding: 10px;
    margin-bottom: 10px;

    background: #f7f7f7;
    border-radius: 8px;
    border-left: 3px solid #999;
}

.hamming-check-row.check-failed {
    border-left-color: #c0392b;
    background: #fdecea;
}

.hamming-check-label {
    margin-bottom: 8px;

    font-size: 12px;
    color: #333;
    line-height: 1.5;
}

.hamming-check-label sub {
    font-size: 10px;
}
/* --- Код Адамара --- */

.hamming-error-row {
    flex-direction: column;
    align-items: center;
    gap: 6px;
}

.checkbox-row input.error-count-input {
    width: 52px;
    height: 24px;
    padding: 0 4px;

    border: 1px solid #999;
    border-radius: 4px;

    font-size: 13px;
    cursor: text;
}

.error-count-hint {
    font-size: 12px;
    color: #666;
}

.error-count-hint.over-limit {
    color: #c0392b;
}

.legend-fail {
    background: #fff3e0;
    border: 2px dashed #c0392b;
}

.hamming-block-card.decode-failed {
    border-style: dashed;
    border-color: #c0392b;
    background: #fff3e0;
}

.hamming-block-card.clickable {
    cursor: pointer;
    transition: transform 0.1s ease, box-shadow 0.15s ease;
}

.hamming-block-card.clickable:hover,
.hamming-block-card.clickable:focus-visible {
    transform: translateY(-2px);
    box-shadow: 0 4px 14px rgba(0, 0, 0, 0.15);
    outline: none;
}

.hadamard-bits .hamming-bit,
.hadamard-bits .hamming-bit-value {
    width: 16px;
}

.hadamard-bits .hamming-bit-value {
    height: 20px;
    font-size: 11px;
}

.hadamard-bits.hamming-bit-row {
    gap: 2px;
    flex-wrap: wrap;
    max-width: 290px;
}

.hadamard-matrix {
    border-collapse: collapse;
    margin: 0 auto;

    font-family: "Courier New", monospace;
    font-size: 11px;
}

.hadamard-matrix th,
.hadamard-matrix td {
    width: 16px;
    height: 16px;
    padding: 1px;

    text-align: center;
}

.hadamard-matrix th {
    color: #999;
    font-weight: normal;
}

.hadamard-matrix td.plus {
    background: #e6f4ea;
    color: #0a6b2e;
}

.hadamard-matrix td.minus {
    background: #fdecea;
    color: #c0392b;
}

.hadamard-matrix tr.used th {
    color: #333;
    font-weight: bold;
}

.hadamard-matrix tr.highlight td {
    outline: 2px solid #333;
    outline-offset: -1px;
}

.correlation-list {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}

.correlation-chip {
    display: flex;
    flex-direction: column;
    align-items: center;

    min-width: 34px;
    padding: 4px 6px;

    background: #f7f7f7;
    border: 1px solid #ddd;
    border-radius: 6px;

    font-size: 11px;
}

.correlation-chip .corr-row {
    color: #999;
    font-size: 10px;
}

.correlation-chip .corr-value {
    font-family: "Courier New", monospace;
    font-weight: bold;
}

.correlation-chip.best {
    background: #e6f4ea;
    border-color: #0a6b2e;
}

.correlation-chip.tie {
    background: #fff3e0;
    border-color: #a15b00;
}

/* --- Группы в окне выбора --- */

.algorithm-group-title {
    margin-top: 8px;
    padding-top: 14px;

    border-top: 1px solid #ddd;

    color: #888;
    font-size: 12px;
    font-weight: bold;
    letter-spacing: 1px;
    text-transform: uppercase;
}

/* --- Моноиды --- */

#transmission-view[hidden],
.monoid-section[hidden],
#monoid-result[hidden],
.monoid-modulus[hidden] {
    display: none;
}

.monoid-section {
    max-width: 900px;
    margin: 0 auto;
}

.math {
    font-family: "Cambria Math", "Times New Roman", serif;
    font-style: italic;
    white-space: nowrap;
}

.monoid-definition {
    padding: 18px 22px;
    margin-bottom: 26px;

    background: white;
    border-left: 4px solid #333;
    border-radius: 8px;

    font-size: 14px;
    line-height: 1.6;
}

.monoid-definition h2 {
    margin: 0 0 6px;
    font-size: 18px;
}

.monoid-definition p,
.monoid-definition ul {
    margin: 6px 0;
}

.monoid-muted {
    color: #666;
    font-size: 13px;
}

.monoid-tabs {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;

    margin-bottom: 18px;
}

.monoid-tab {
    padding: 8px 14px;

    background: white;
    border: 1px solid #999;
    border-radius: 20px;

    color: #333;
    font-size: 13px;
}

.monoid-tab:hover {
    background: #eee;
}

.monoid-tab.active {
    background: #333;
    border-color: #333;
    color: white;
}

.monoid-example {
    padding: 22px;

    background: white;
    border: 2px solid #333;
    border-radius: 10px;
}

.monoid-example > p {
    margin: 8px 0 12px;
    font-size: 14px;
    line-height: 1.5;
}

.monoid-example-head {
    display: flex;
    flex-wrap: wrap;
    align-items: baseline;
    justify-content: space-between;
    gap: 10px;
}

.monoid-example-head h3 {
    margin: 0;
    font-size: 18px;
}

.monoid-signature {
    padding: 4px 10px;

    background: #f5f5f5;
    border-radius: 6px;

    font-size: 16px;
}

.monoid-props {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;

    margin-bottom: 18px;
}

.monoid-prop {
    padding: 3px 10px;

    border-radius: 12px;

    font-size: 12px;
}

.monoid-prop.yes {
    background: #e6f4ea;
    color: #0a6b2e;
}

.monoid-prop.no {
    background: #fff3e0;
    color: #a15b00;
}

.monoid-input label[for] {
    display: block;
    margin-bottom: 8px;
    font-weight: bold;
}

.monoid-modulus {
    display: flex;
    align-items: center;
    gap: 6px;

    font-family: "Cambria Math", "Times New Roman", serif;
    font-style: italic;
    white-space: nowrap;
}

.monoid-modulus input {
    width: 80px;
    flex: none;
}

.monoid-input-hint {
    margin: 8px 0 0;
    color: #666;
    font-size: 12px;
}

.monoid-section .error {
    margin-top: 14px;
}

.monoid-section .code-block {
    margin: 26px 0 0;
}

.monoid-section .trace-chip {
    min-width: 0;
    padding: 8px 12px;
}

.monoid-section .trace-chip .chip-top {
    font-size: 13px;
    font-weight: normal;
}

.monoid-section .trace-chip .chip-bottom {
    font-size: 15px;
    font-weight: bold;
    letter-spacing: 0;
}

.monoid-checks {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.monoid-check {
    padding: 10px 14px;

    background: #f7f7f7;
    border-left: 3px solid #999;
    border-radius: 8px;

    font-size: 13px;
    line-height: 1.6;
}

.monoid-check.ok {
    background: #e6f4ea;
    border-left-color: #0a6b2e;
}

.monoid-check.fail {
    background: #fdecea;
    border-left-color: #c0392b;
}

.monoid-check.info {
    background: #fff3e0;
    border-left-color: #a15b00;
}

.monoid-check-title {
    font-weight: bold;
}

.monoid-check code {
    font-family: "Courier New", monospace;
    word-break: break-all;
}

.monoid-cayley th:first-child {
    color: #333;
    font-weight: bold;
}

.monoid-cayley td {
    width: 24px;
    height: 24px;
    border: 1px solid #eee;
}

.monoid-cayley td.identity-cell {
    background: #e6f4ea;
    color: #0a6b2e;
    font-weight: bold;
}

.monoid-cayley td.zero-cell {
    color: #bbb;
}

/* --- Диофантовы уравнения --- */

.dioph-params {
    display: flex;
    flex-wrap: wrap;
    align-items: flex-end;
    gap: 12px;

    margin-top: 6px;
}

.dioph-fields {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.param-field {
    display: flex;
    flex-direction: column;
    gap: 4px;

    font-size: 13px;
    color: #555;
}

.param-field span {
    font-family: "Cambria Math", "Times New Roman", serif;
    font-style: italic;
}

.param-field input {
    width: 120px;
    flex: none;
}

#diophantine-result .code-block,
#congruence-result .code-block,
#residue-result .code-block {
    margin: 24px 0 0;
}

.dioph-steps {
    margin: 0;
    padding-left: 22px;

    font-size: 14px;
    line-height: 1.7;
}

.dioph-steps li + li {
    margin-top: 4px;
}

.dioph-table td {
    font-family: "Cambria Math", "Cambria", "Times New Roman", serif;
    font-size: 15px;
    font-variant-numeric: tabular-nums;
}

.dioph-table tr.highlight td {
    background: #e6f4ea;
    color: #0a6b2e;
    font-weight: bold;
}

.dioph-table-wrap {
    max-height: 420px;
    overflow: auto;
}

#diophantine-result .monoid-check,
#congruence-result .monoid-check,
#residue-result .monoid-check {
    margin-top: 14px;
    font-size: 14px;
}

.dioph-result-text {
    font-family: "Cambria Math", "Times New Roman", serif;
    font-size: 16px;
}

.param-field input[type="text"] {
    width: 170px;
}

/* --- Шифр Эль-Гамаля --- */

.elgamal-key-row {
    display: flex;
    flex-wrap: wrap;
    align-items: flex-end;
    justify-content: center;
    gap: 12px;

    margin-bottom: 30px;
}

.elgamal-key-row[hidden],
#elgamal-section[hidden] {
    display: none;
}

.elgamal-key-row .frequency-source-label {
    align-self: center;
}

.elgamal-key-hint {
    flex-basis: 100%;
    text-align: center;
}

.elgamal-key-row .param-field input[type="text"] {
    width: 220px;
}

.elgamal-key-row .elgamal-bits-field input {
    width: 90px;
}

.dioph-table td.long-number {
    min-width: 180px;
    overflow-wrap: anywhere;
}

#elgamal-sections .code-block {
    margin: 24px 0 0;
}

#elgamal-sections .monoid-check {
    margin-top: 14px;
    font-size: 14px;
}