:root {
    --bg: #f4efe7;
    --bg-accent: #efe3cd;
    --surface: rgba(255, 250, 242, 0.88);
    --surface-strong: #fffaf2;
    --surface-soft: rgba(255, 247, 235, 0.76);
    --text: #1e1f1d;
    --muted: #5f615c;
    --navy: #1f3140;
    --navy-soft: #324d63;
    --gold: #c68b2c;
    --gold-soft: #e7bf77;
    --gold-pale: #f1ddae;
    --line: rgba(31, 49, 64, 0.12);
    --shadow: 0 24px 60px rgba(37, 42, 48, 0.14);
    --success-color: #166534;
    --info-color: #1d4ed8;
    --error-color: #991b1b;
}

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

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    min-height: 100vh;
    color: var(--text);
    font-family: Georgia, "Times New Roman", serif;
    background:
        radial-gradient(circle at top left, rgba(255, 255, 255, 0.9), transparent 24%),
        radial-gradient(circle at 82% 18%, rgba(198, 139, 44, 0.2), transparent 20%),
        linear-gradient(180deg, #f7f0e5 0%, #efe5d5 52%, #f4efe7 100%);
}

a {
    color: inherit;
    text-decoration: none;
}

button,
input,
select,
textarea {
    font: inherit;
}

.dashboard-nav {
    width: 100%;
    margin: 0;
    padding: 18px max(16px, calc((100vw - 1200px) / 2)) 16px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
    position: sticky;
    top: 0;
    z-index: 20;
    border-top: 0;
    border-right: 4px solid #12212d;
    border-bottom: 4px solid #12212d;
    border-left: 4px solid #12212d;
    background: linear-gradient(180deg, rgba(17, 29, 39, 0.96), rgba(31, 49, 64, 0.94));
    backdrop-filter: blur(12px);
    box-shadow: 0 18px 40px rgba(31, 49, 64, 0.18);
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    color: #fff7eb;
    font-size: 18px;
    font-weight: 700;
    letter-spacing: 0.03em;
}

.brand-mark {
    width: 40px;
    height: 40px;
    display: grid;
    place-items: center;
    border-radius: 8px;
    background: linear-gradient(135deg, var(--gold), var(--gold-soft));
    color: #2c2215;
    font-size: 22px;
}

.nav-actions {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    justify-content: flex-end;
    gap: 12px;
}

.nav-link,
.nav-link-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 46px;
    padding: 11px 16px;
    border: 2px solid transparent;
    background: rgba(255, 255, 255, 0.06);
    color: #ecf4fb;
    font-weight: 700;
    cursor: pointer;
    transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

.lang-switch {
    min-width: 68px;
    border-color: rgba(231, 191, 119, 0.45);
}

.nav-link:hover,
.nav-link-button:hover {
    transform: translateY(-2px);
    border-color: rgba(231, 191, 119, 0.45);
}

.nav-logout-form {
    margin: 0;
}

.account-shortcut {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    min-height: 46px;
    padding: 8px 12px 8px 8px;
    background: rgba(255, 255, 255, 0.08);
    border: 2px solid rgba(231, 191, 119, 0.26);
    color: #fff7eb;
    transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}

.account-shortcut:hover {
    transform: translateY(-2px);
    border-color: rgba(231, 191, 119, 0.48);
}

.account-avatar {
    width: 36px;
    height: 36px;
    display: grid;
    place-items: center;
    border-radius: 999px;
    background: linear-gradient(135deg, var(--gold), var(--gold-soft));
    color: #2d2418;
    font-weight: 700;
}

.account-copy {
    display: grid;
    gap: 2px;
}

.account-label {
    font-size: 12px;
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

.account-name {
    font-family: "Trebuchet MS", "Segoe UI", sans-serif;
    font-size: 14px;
}

.settings-trigger {
    position: fixed;
    left: 0;
    top: 180px;
    z-index: 18;
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 14px 16px;
    border: 0;
    border-left: 0;
    background: linear-gradient(135deg, var(--navy), var(--navy-soft));
    color: #fff7eb;
    box-shadow: 0 16px 34px rgba(31, 49, 64, 0.18);
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.settings-trigger:hover {
    transform: translateX(4px);
}

.settings-trigger-arrow {
    font-size: 20px;
    line-height: 1;
}

.settings-trigger-label {
    font-size: 14px;
    font-weight: 700;
    letter-spacing: 0.04em;
}

.container {
    width: min(1200px, calc(100vw - 32px));
    margin: 0 auto;
    padding: 34px 0 56px;
}

.card {
    padding: 28px;
    margin-bottom: 24px;
    border-radius: 12px;
    background: linear-gradient(135deg, rgba(255, 250, 242, 0.94), rgba(245, 230, 205, 0.8));
    border: 1px solid var(--line);
    box-shadow: var(--shadow);
}

.flash-stack {
    display: grid;
    gap: 12px;
    margin-bottom: 18px;
}

.flash-message {
    margin: 0;
    padding: 12px 14px;
    border-radius: 8px;
    font-family: "Trebuchet MS", "Segoe UI", sans-serif;
}

.flash-message.success {
    color: var(--success-color);
    background: rgba(220, 252, 231, 0.92);
}

.flash-message.info {
    color: var(--info-color);
    background: rgba(219, 234, 254, 0.92);
}

.flash-message.error {
    color: var(--error-color);
    background: rgba(254, 226, 226, 0.92);
}

.section-kicker {
    margin: 0 0 12px;
    color: var(--navy-soft);
    text-transform: uppercase;
    letter-spacing: 0.14em;
    font-size: 13px;
    font-weight: 700;
}

.dashboard-intro {
    text-align: center;
}

.dashboard-intro h1 {
    margin: 0;
    line-height: 0.96;
    letter-spacing: -0.03em;
    font-size: clamp(2.4rem, 4.4vw, 4.8rem);
    color: #182029;
}

.dashboard-intro-text,
.board-mode-text,
.solver-message,
.solver-group-text,
.history-subtitle,
.board-size-info,
.sidebar p,
.sidebar-hint,
.modal-content p,
.save-point-meta,
.save-point-preview,
.save-point-note {
    font-family: "Trebuchet MS", "Segoe UI", sans-serif;
    line-height: 1.65;
    color: var(--muted);
}

.dashboard-intro-text {
    max-width: 760px;
    margin: 18px auto 0;
    font-size: 18px;
}

.btn {
    min-height: 50px;
    padding: 12px 18px;
    border: none;
    border-radius: 0;
    background: linear-gradient(135deg, var(--gold), var(--gold-soft));
    color: #2d2418;
    font-weight: 700;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease, opacity 0.2s ease;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 24px rgba(31, 49, 64, 0.16);
}

.btn:active {
    transform: scale(0.98);
}

.btn:disabled,
.btn:disabled:hover {
    transform: none;
    opacity: 0.55;
    box-shadow: none;
    cursor: not-allowed;
}

.btn.secondary {
    background: linear-gradient(135deg, var(--navy), var(--navy-soft));
    color: #f9fbfd;
}

.btn.danger,
.btn.ghost {
    background: rgba(255, 255, 255, 0.68);
    color: var(--navy);
    border: 1px solid rgba(31, 49, 64, 0.16);
}

.btn.active,
.btn.accent {
    background: linear-gradient(135deg, var(--gold), #f0c35b);
    color: #241b0d;
}

.mode-switch {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 16px;
    margin-top: 28px;
}

.mode-switch .btn {
    min-width: 220px;
    min-height: 68px;
    padding: 18px 28px;
    font-size: 1.15rem;
}

.game-card {
    text-align: center;
}

.game-card-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 18px;
    text-align: left;
}

.game-card-copy {
    max-width: 760px;
}

.game-card h2,
.card h3,
.solver-panel h3,
.sidebar h3,
.modal-header h3 {
    margin: 0;
    color: #182029;
}

.game-card h2 {
    line-height: 0.98;
    letter-spacing: -0.03em;
    font-size: clamp(2rem, 3.2vw, 3.2rem);
}

.board-mode-text {
    margin: 16px 0 0;
    font-size: 18px;
}

.info-button {
    min-height: 48px;
    padding: 12px 18px;
    border: 1px solid rgba(31, 49, 64, 0.14);
    background: rgba(255, 255, 255, 0.66);
    color: var(--navy);
    font-weight: 700;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.info-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 24px rgba(31, 49, 64, 0.12);
}

.board-size-info {
    margin: 18px 0 10px;
    font-size: 16px;
}

.game-stats {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 14px;
    margin: 18px 0 14px;
    text-align: left;
}

.game-stat-card {
    padding: 16px 18px;
    border-radius: 10px;
    background: rgba(255, 255, 255, 0.56);
    border: 1px solid rgba(31, 49, 64, 0.08);
}

.game-stat-label {
    margin: 0 0 8px;
    font-size: 13px;
    color: var(--navy-soft);
    text-transform: uppercase;
    letter-spacing: 0.12em;
    font-weight: 700;
}

.game-stat-value {
    margin: 0;
    font-size: 28px;
    font-weight: 700;
    color: #1e293b;
    font-variant-numeric: tabular-nums;
}

.game-stat-status {
    font-size: 22px;
}

#statusMessage {
    min-height: 24px;
    margin: 0 0 10px;
    font-family: "Trebuchet MS", "Segoe UI", sans-serif;
    font-weight: 700;
}

.solved-celebration {
    margin: 0 auto 18px;
    padding: 18px 20px;
    max-width: 760px;
    border: 1px solid rgba(198, 139, 44, 0.28);
    background:
        radial-gradient(circle at top left, rgba(255, 255, 255, 0.75), transparent 35%),
        linear-gradient(135deg, rgba(240, 195, 91, 0.96), rgba(231, 191, 119, 0.9));
    color: #2d2418;
    box-shadow: 0 18px 40px rgba(198, 139, 44, 0.18);
    animation: solvedPop 0.55s ease;
}

.solved-celebration-title {
    margin: 0;
    font-size: clamp(1.8rem, 3vw, 2.6rem);
    font-weight: 700;
    letter-spacing: -0.03em;
}

.solved-celebration-text {
    margin: 8px 0 0;
    font-family: "Trebuchet MS", "Segoe UI", sans-serif;
    font-size: 16px;
    line-height: 1.55;
}

.board {
    overflow-x: auto;
    padding-bottom: 8px;
}

.board-grid {
    --label-size: var(--cell-size);
    --cell-size: 60px;
    display: grid;
    grid-template-columns: var(--label-size) repeat(var(--board-size, 8), var(--cell-size));
    grid-template-rows: var(--label-size) repeat(var(--board-size, 8), var(--cell-size));
    margin: 20px auto;
    width: max-content;
    background: var(--navy);
    border: 6px solid var(--navy);
    border-radius: 10px;
    overflow: hidden;
    max-width: 100%;
}

.label {
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    background: var(--navy);
    color: #fff7eb;
    width: var(--label-size);
    height: var(--label-size);
    font-size: clamp(13px, 1.4vw, 18px);
    text-align: center;
}

.cell {
    width: var(--cell-size);
    height: var(--cell-size);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: calc(var(--cell-size) * 0.5);
    cursor: pointer;
    transition: transform 0.2s ease, background 0.2s ease;
}

.cell:hover {
    transform: scale(1.05);
}

.white {
    background: #f7e6ca;
}

.black {
    background: #92613a;
    color: #fff5ea;
}

.invalid {
    background: #d65555 !important;
}

.solver-panel {
    margin-top: 18px;
    padding: 18px;
    border-radius: 12px;
    border: 1px solid rgba(31, 49, 64, 0.1);
    background: rgba(255, 250, 242, 0.74);
    text-align: left;
}

.solver-panel-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 16px;
}

.solver-panel h3 {
    margin-bottom: 8px;
}

.solver-message {
    margin: 0;
}

.solver-step-info {
    margin: 0;
    padding: 8px 12px;
    background: rgba(255, 255, 255, 0.74);
    border: 1px solid rgba(31, 49, 64, 0.12);
    color: var(--navy);
    font-size: 14px;
    font-weight: 700;
    white-space: nowrap;
}

.solver-groups {
    display: grid;
    grid-template-columns: minmax(0, 1.35fr) minmax(260px, 0.65fr);
    gap: 16px;
    margin-top: 18px;
}

.solver-group {
    padding: 18px;
    border: 1px solid rgba(31, 49, 64, 0.1);
    background: rgba(255, 255, 255, 0.58);
}

.solver-group h4 {
    margin: 0 0 8px;
    color: #182029;
    font-size: 1.15rem;
}

.solver-group-text {
    margin: 0;
    font-size: 15px;
}

.solver-controls {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 10px;
    margin-top: 16px;
}

.instant-solver-actions {
    margin-top: 16px;
}

.instant-solver-actions .btn {
    width: 100%;
}

.solver-speed {
    display: grid;
    grid-template-columns: auto 1fr auto;
    align-items: center;
    gap: 12px;
    margin-top: 16px;
}

.solver-speed input[type="range"] {
    width: 100%;
}

.solver-speed-label {
    font-weight: 700;
    color: var(--navy);
}

.solver-speed-value {
    min-width: 62px;
    text-align: right;
    color: var(--muted);
    font-variant-numeric: tabular-nums;
}

.controls {
    margin-top: 18px;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 10px;
}

.controls-save-row {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 10px;
    width: min(420px, 100%);
}

.settings-sidebar-actions {
    margin-top: 18px;
    display: grid;
    gap: 10px;
}

.section-header,
.history-header,
.sidebar-header,
.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 12px;
}

.section-badge {
    padding: 8px 12px;
    background: rgba(255, 255, 255, 0.66);
    border: 1px solid rgba(31, 49, 64, 0.1);
    color: var(--navy);
    font-family: "Trebuchet MS", "Segoe UI", sans-serif;
    font-size: 14px;
    font-weight: 700;
}

#queenList {
    list-style: none;
    padding: 0;
    margin: 18px 0 0;
    display: grid;
    gap: 10px;
}

#queenList li {
    padding: 12px 14px;
    background: rgba(255, 255, 255, 0.56);
    border: 1px solid rgba(31, 49, 64, 0.08);
    border-radius: 8px;
    font-family: "Trebuchet MS", "Segoe UI", sans-serif;
    color: var(--navy);
}

#queenList li.empty {
    color: var(--muted);
}

.history-header h3 {
    margin-top: 4px;
}

.history-subtitle {
    margin: 8px 0 0;
    font-size: 15px;
}

.history-table-wrapper {
    overflow-x: auto;
    margin-top: 18px;
}

.history-table {
    width: 100%;
    border-collapse: collapse;
    min-width: 720px;
}

.history-table th,
.history-table td {
    padding: 12px 10px;
    border-bottom: 1px solid rgba(31, 49, 64, 0.08);
    text-align: left;
    font-family: "Trebuchet MS", "Segoe UI", sans-serif;
}

.history-table th {
    color: var(--navy);
    font-size: 14px;
}

.history-table td {
    color: var(--muted);
    font-size: 14px;
}

.history-empty {
    color: var(--muted);
    text-align: center !important;
}

.sidebar {
    position: fixed;
    top: 0;
    right: 0;
    width: min(360px, 92vw);
    height: 100vh;
    padding: 24px;
    background: linear-gradient(180deg, rgba(255, 250, 242, 0.98), rgba(245, 230, 205, 0.96));
    border-left: 1px solid rgba(31, 49, 64, 0.12);
    box-shadow: -10px 0 24px rgba(15, 23, 42, 0.18);
    transform: translateX(100%);
    transition: transform 0.25s ease;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    overscroll-behavior: contain;
    z-index: 30;
}

.sidebar.open {
    transform: translateX(0);
}

.settings-sidebar {
    left: 0;
    right: auto;
    border-left: 0;
    border-right: 1px solid rgba(31, 49, 64, 0.12);
    box-shadow: 10px 0 24px rgba(15, 23, 42, 0.18);
    transform: translateX(-100%);
}

.settings-sidebar.open {
    transform: translateX(0);
}

.save-points-sidebar {
    width: min(400px, 94vw);
}

.sidebar-label {
    display: block;
    margin-top: 18px;
    margin-bottom: 8px;
    font-weight: 700;
    color: var(--navy);
}

.sidebar input[type="range"] {
    width: 100%;
}

.sidebar-input,
.sidebar select,
.sidebar textarea,
.sidebar input[type="text"] {
    width: 100%;
    padding: 12px 14px;
    border: 1px solid rgba(31, 49, 64, 0.16);
    border-radius: 0;
    background: rgba(255, 255, 255, 0.9);
    color: var(--text);
}

.sidebar-textarea {
    resize: vertical;
    min-height: 96px;
}

.sidebar-checkbox {
    display: flex;
    align-items: center;
    gap: 10px;
    margin: 16px 0 18px;
    color: var(--navy);
    font-family: "Trebuchet MS", "Segoe UI", sans-serif;
}

.sidebar-size-row {
    margin: 12px 0 18px;
    font-size: 18px;
}

.save-points-list {
    display: grid;
    gap: 12px;
    margin-top: 18px;
}

.save-point-filters {
    display: grid;
    gap: 8px;
    margin-top: 18px;
    padding-bottom: 16px;
    border-bottom: 1px solid rgba(31, 49, 64, 0.08);
}

.save-point-card {
    border: 1px solid rgba(31, 49, 64, 0.1);
    padding: 14px;
    background: rgba(255, 255, 255, 0.56);
}

.save-point-card h4 {
    margin: 0 0 8px;
    color: #1e293b;
}

.save-point-meta,
.save-point-preview,
.save-point-note {
    margin: 6px 0 0;
    font-size: 14px;
}

.save-point-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 14px;
}

.sidebar-backdrop {
    position: fixed;
    inset: 0;
    background: rgba(15, 23, 42, 0.3);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.25s ease;
    z-index: 20;
}

.sidebar-backdrop.visible {
    opacity: 1;
    pointer-events: auto;
}

.modal-backdrop {
    position: fixed;
    inset: 0;
    background: rgba(15, 23, 42, 0.42);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.25s ease;
    z-index: 40;
}

.modal-backdrop.visible {
    opacity: 1;
    pointer-events: auto;
}

.modal {
    position: fixed;
    top: 50%;
    left: 50%;
    width: min(680px, calc(100vw - 32px));
    max-height: min(82vh, 720px);
    padding: 24px;
    background: linear-gradient(180deg, rgba(255, 250, 242, 0.98), rgba(245, 230, 205, 0.96));
    border-radius: 12px;
    border: 1px solid rgba(31, 49, 64, 0.12);
    box-shadow: 0 20px 60px rgba(15, 23, 42, 0.28);
    transform: translate(-50%, -48%);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.25s ease, transform 0.25s ease;
    overflow-y: auto;
    z-index: 50;
}

.modal.open {
    opacity: 1;
    pointer-events: auto;
    transform: translate(-50%, -50%);
}

.modal-content {
    margin-top: 16px;
    text-align: left;
}

.modal-content h4 {
    margin: 18px 0 8px;
    color: var(--navy);
}

.cell.solver-place {
    box-shadow: inset 0 0 0 4px #2f8f53;
    animation: solverPulse 0.35s ease;
}

.cell.solver-remove {
    box-shadow: inset 0 0 0 4px #d08a24;
    animation: solverPulse 0.35s ease;
}

.cell.solver-solution {
    box-shadow: inset 0 0 0 4px #2563eb;
    animation: solverPulse 0.35s ease;
}

@keyframes solverPulse {
    0% {
        transform: scale(0.97);
    }

    50% {
        transform: scale(1.03);
    }

    100% {
        transform: scale(1);
    }
}

@keyframes solvedPop {
    0% {
        opacity: 0;
        transform: translateY(-10px) scale(0.96);
    }

    60% {
        opacity: 1;
        transform: translateY(2px) scale(1.02);
    }

    100% {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

@media (max-width: 980px) {
    .solver-groups {
        grid-template-columns: 1fr;
    }

    .solver-controls {
        grid-template-columns: 1fr;
    }

    .game-card-header,
    .history-header,
    .section-header {
        flex-direction: column;
    }
}

@media (max-width: 760px) {
    .dashboard-nav {
        position: static;
        padding: 18px 16px;
        border-left-width: 0;
        border-right-width: 0;
        flex-direction: column;
        align-items: flex-start;
    }

    .brand {
        width: 100%;
        font-size: 16px;
    }

    .nav-actions {
        width: 100%;
        justify-content: flex-start;
    }

    .account-name {
        display: none;
    }

    .settings-trigger {
        top: auto;
        bottom: 16px;
        left: 12px;
        max-width: calc(100vw - 24px);
    }

    .container {
        width: 100%;
        padding-top: 22px;
    }

    .card {
        padding: 22px 18px;
    }

    .game-card {
        padding-left: 8px;
        padding-right: 8px;
    }

    .board {
        margin-left: -4px;
        margin-right: -4px;
        padding-bottom: 4px;
    }

    .board-grid {
        margin: 12px auto;
        border-width: 4px;
        border-radius: 8px;
    }

    .label {
        font-size: 12px;
    }

    .game-stats,
    .solver-speed {
        grid-template-columns: 1fr;
    }

    .mode-switch .btn {
        min-width: min(100%, 280px);
    }

    .controls {
        justify-content: stretch;
    }

    .controls>.btn,
    .save-point-actions .btn {
        width: 100%;
    }

    .controls-save-row {
        width: 100%;
    }

    .sidebar {
        width: min(100%, calc(100vw - 24px));
    }

    .modal {
        width: min(100%, calc(100vw - 24px));
        padding: 20px;
    }
}