:root {
    --bg-color: #f4f4f4;
    --text-color: #333;
    --primary-color: #435a64;
    --secondary-color: #607d8b;
    --accent-color: #ff9800;
    --fixed-bg: #e0e0e0;
    --input-bg: #fff;
    --border-color: #999;
}

body {
    font-family: 'Roboto Mono', monospace;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    line-height: 1.6;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 20px;
}

header {
    background: var(--primary-color);
    color: white;
    padding: 1rem 0;
    border-bottom: 3px solid var(--accent-color);
}

header h1 {
    margin: 0;
    padding: 0;
    font-size: 1.5rem;
}

nav {
    margin-top: 10px;
}

nav a,
nav span {
    color: white;
    margin-right: 15px;
    text-decoration: none;
    font-size: 0.9rem;
}

nav a:hover {
    text-decoration: underline;
}

main {
    padding: 2rem 0;
}

.puzzle-container {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.grid-layout {
    display: grid;
    grid-template-columns: min-content auto;
    grid-template-rows: 40px repeat(6, 62px);
    gap: 0;
    margin-top: 30px;
}

.label-header {
    grid-column: 1;
    grid-row: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: bold;
    color: var(--secondary-color);
    text-transform: uppercase;
    background: #f1f5f9;
    border: 1px solid var(--border-color);
    border-right: none;
}

.grid-column {
    grid-column: 2;
    grid-row: 1 / span 7;
}

.grid-header-placeholder {
    height: 40px;
    background: #f1f5f9;
    border: 1px solid var(--border-color);
    border-bottom: none;
    box-sizing: border-box;
}

.row-label {
    grid-column: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    font-size: 0.8rem;
    padding: 0 15px;
    background: #f8fafc;
    border: 1px solid var(--border-color);
    border-top: none;
    border-right: none;
    box-sizing: border-box;
    white-space: nowrap;
}

.row-label:nth-child(2) {
    grid-row: 2;
}

.row-label:nth-child(3) {
    grid-row: 3;
}

.row-label:nth-child(4) {
    grid-row: 4;
}

.row-label:nth-child(5) {
    grid-row: 5;
}

.row-label:nth-child(6) {
    grid-row: 6;
}

.row-label:nth-child(7) {
    grid-row: 7;
}

.row-label span {
    display: block;
}

.grid {
    display: inline-block;
    border: 2px solid var(--border-color);
    background: var(--border-color);
}

.row {
    display: flex;
}

.cell {
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 1px;
    font-size: 1.5rem;
    font-weight: bold;
    cursor: pointer;
    user-select: none;
}

.cell.fixed {
    background-color: var(--fixed-bg);
    cursor: default;
}

.cell.input {
    background-color: var(--input-bg);
}

.cell.input:hover {
    background-color: #f9f9f9;
}

.controls {
    margin-top: 20px;
}

.btn {
    padding: 10px 20px;
    background: var(--primary-color);
    color: white;
    border: none;
    cursor: pointer;
    font-family: inherit;
    font-size: 1rem;
}

.btn:hover {
    background: var(--secondary-color);
}

.btn-secondary {
    background: #777;
}

.message {
    margin-top: 20px;
    font-weight: bold;
    height: 1.5rem;
}


.auth-form {
    max-width: 400px;
    margin: 0 auto;
    background: white;
    padding: 30px;
    border: 1px solid #ddd;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
}

.form-group input {
    width: 100%;
    padding: 8px;
    box-sizing: border-box;
    font-family: inherit;
}

.captcha-container {
    display: flex;
    align-items: center;
    gap: 10px;
}

.captcha-container img {
    border: 1px solid #ccc;
}

.error {
    color: red;
    margin-bottom: 20px;
}

.recovery-box {
    background: #fdf6e3;
    padding: 15px;
    border: 1px solid #eee8d5;
    margin: 20px 0;
}

.key {
    background: #eee;
    padding: 2px 5px;
}

.warning {
    color: #b58900;
}

.history-table {
    width: 100%;
    border-collapse: collapse;
    background: white;
}

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

.history-table th {
    background: #f2f2f2;
}

.list-link {
    color: var(--primary-color);
    text-decoration: none;
}

.row-label.invalid {
    background-color: #fee2e2;
    color: #991b1b;
    border-left: 4px solid #ef4444;
}

.row-label.valid {
    background-color: #dcfce7;
    color: #166534;
    border-left: 4px solid #22c55e;
}

.instructions {
    margin-top: 40px;
    width: 100%;
}

.instruction-grid {
    display: flex;
    gap: 15px;
    justify-content: stretch;
}

.rule-card {
    flex: 1;
    background: white;
    padding: 15px;
    border: 1px solid #ddd;
    border-radius: 4px;
}

.rule-card h4 {
    margin: 0 0 8px 0;
    color: var(--primary-color);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.rule-card p {
    font-size: 0.85rem;
    margin: 0;
    color: #555;
}

.cell.invalid {
    background-color: #fca5a5 !important;
    color: white;
}

.cell.input:focus {
    outline: 2px solid var(--accent-color);
}

.timer-container {
    background: #435a64;
    color: white;
    padding: 10px 20px;
    border-radius: 4px;
    margin-bottom: 20px;
    font-weight: bold;
    font-family: 'Roboto Mono', monospace;
    text-align: center;
}

#timer-countdown {
    color: var(--accent-color);
}

footer {
    text-align: center;
    padding: 2rem 0;
    color: #777;
    font-size: 0.8rem;
}