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

body, html {
  height: 100%;
  margin: 0;
  background: #1a1a2e;
  width: 100%;
  font-family: "Lucida Sans", "Segoe UI", sans-serif;
  display: flex;
  overflow: hidden;
}

/* ── Layout ── */

.sidebar-toggle,
.sidebar-backdrop {
  display: none;
}

.sidebar {
  width: 260px;
  min-width: 260px;
  height: 100vh;
  background: #12122a;
  border-right: 1px solid rgba(255, 255, 255, 0.07);
  display: flex;
  flex-direction: column;
  padding: 0;
  overflow: hidden;
}

.game {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 24px;
  padding: 32px;
  overflow: auto;
}

/* ── Sidebar brand ── */

.sidebar-brand {
  padding: 28px 20px 20px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.07);
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.brand-label {
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.4);
}

.brand-name {
  font-size: 38px;
  font-weight: 800;
  letter-spacing: -0.02em;
  text-decoration: none;
  color: transparent;
  -webkit-text-fill-color: transparent;
  -webkit-text-stroke-width: 2px;
  -webkit-text-stroke-color: rgba(255, 255, 255, 0.85);
  transition: -webkit-text-stroke-color 0.2s;
  line-height: 1;
}

.brand-name:hover {
  -webkit-text-stroke-color: #e07b39;
}

/* ── Tabs ── */

.tabs {
  display: flex;
  border-bottom: 1px solid rgba(255, 255, 255, 0.07);
}

.tab {
  flex: 1;
  background: none;
  border: none;
  padding: 12px 4px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.35);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  transition: color 0.15s, border-color 0.15s;
}

.tab:hover {
  color: rgba(255, 255, 255, 0.7);
}

.tab.active {
  color: #e07b39;
  border-bottom-color: #e07b39;
}

/* ── Tab content ── */

.tab-content {
  flex: 1;
  overflow-y: auto;
  padding: 20px 16px;
  scrollbar-width: thin;
  scrollbar-color: rgba(255,255,255,0.1) transparent;
}

.tab-content.hidden {
  display: none;
}

.tip-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.tip-list li {
  font-size: 13px;
  line-height: 1.55;
  color: rgba(255, 255, 255, 0.65);
  padding: 10px 12px;
  background: rgba(255, 255, 255, 0.04);
  border-left: 3px solid #e07b39;
  border-radius: 0 6px 6px 0;
}

.tip-list li strong {
  color: #e07b39;
}

kbd {
  display: inline-block;
  font-size: 11px;
  font-family: inherit;
  font-weight: 700;
  color: #fff;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 4px;
  padding: 1px 6px;
}

/* ── Utility ── */

.hidden {
  display: none !important;
}

/* ── Menu ── */

#menu {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 32px;
  width: 100%;
  max-width: 480px;
}

.menu-header {
  text-align: center;
}

.menu-title {
  font-size: 52px;
  font-weight: 800;
  letter-spacing: -0.03em;
  margin: 0 0 6px;
  color: transparent;
  -webkit-text-fill-color: transparent;
  -webkit-text-stroke-width: 2px;
  -webkit-text-stroke-color: rgba(255, 255, 255, 0.9);
}

.menu-subtitle {
  margin: 0;
  font-size: 13px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.35);
}

/* Mode cards */

.mode-cards {
  display: flex;
  gap: 16px;
  width: 100%;
}

.mode-card {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  padding: 20px 12px;
  background: rgba(255, 255, 255, 0.04);
  border: 2px solid rgba(255, 255, 255, 0.08);
  border-radius: 12px;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s, transform 0.15s;
}

.mode-card:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.2);
  transform: translateY(-2px);
}

.mode-card.active {
  border-color: #e07b39;
  background: rgba(224, 123, 57, 0.12);
}

.mode-icon {
  font-size: 32px;
  line-height: 1;
}

.mode-name {
  font-size: 14px;
  font-weight: 700;
  color: #fff;
  letter-spacing: 0.02em;
}

.mode-desc {
  font-size: 11px;
  color: rgba(255, 255, 255, 0.4);
  letter-spacing: 0.04em;
}

/* Version / difficulty selectors */

.version-select,
.difficulty-select {
  display: flex;
  flex-direction: column;
  gap: 8px;
  width: 100%;
}

.version-select label,
.difficulty-select label {
  font-size: 12px;
  color: rgba(255, 255, 255, 0.5);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.version-options,
.difficulty-options {
  display: flex;
  gap: 8px;
}

.version-btn,
.diff-btn {
  flex: 1;
  padding: 8px 0;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 6px;
  color: rgba(255, 255, 255, 0.6);
  font-size: 13px;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
}

.version-btn {
  padding: 7px 0;
  font-size: 12px;
}

.version-btn:hover,
.diff-btn:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.2);
  color: rgba(255, 255, 255, 0.9);
}

.version-btn.active,
.diff-btn.active {
  border-color: #e07b39;
  background: rgba(224, 123, 57, 0.12);
  color: #e07b39;
}

/* Player inputs */

.player-inputs {
  display: flex;
  gap: 16px;
  width: 100%;
}

.input-group {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.input-group label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.45);
}

.input-group input {
  padding: 10px 14px;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 8px;
  color: #fff;
  font-size: 14px;
  font-family: inherit;
  outline: none;
  transition: border-color 0.15s, background 0.15s;
}

.input-group input::placeholder {
  color: rgba(255, 255, 255, 0.25);
}

.input-group input:focus {
  border-color: #e07b39;
  background: rgba(255, 255, 255, 0.09);
}

/* Start button */

#start-btn {
  width: 100%;
  padding: 14px;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #fff;
  background: linear-gradient(135deg, #e07b39, #c0522a);
  border: none;
  border-radius: 10px;
  cursor: pointer;
  box-shadow: 0 4px 20px rgba(192, 82, 42, 0.4);
  transition: transform 0.15s, box-shadow 0.15s;
}

#start-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 26px rgba(192, 82, 42, 0.55);
}

#start-btn:active {
  transform: translateY(0);
  box-shadow: 0 2px 10px rgba(192, 82, 42, 0.35);
}

/* ── Game container ── */

#game-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
}

/* ── Board wrapper (horizontal: panel | board | panel) ── */

.board-wrapper {
  display: flex;
  flex-direction: row;
  align-items: stretch;
  gap: 16px;
}

.board-area {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

/* ── Player panels (vertical, flanking the board) ── */

.player-panel {
  width: 110px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 16px 10px;
  background: rgba(255, 255, 255, 0.04);
  border: 2px solid transparent;
  border-radius: 12px;
  transition: border-color 0.2s, background 0.2s;
}

.player-panel.active {
  border-color: #e07b39;
  background: rgba(224, 123, 57, 0.07);
}

.panel-piece {
  font-size: 28px;
  line-height: 1;
}

.panel-name {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.45);
  text-align: center;
  word-break: break-word;
}

.panel-score {
  font-size: 40px;
  font-weight: 800;
  color: #fff;
  line-height: 1;
}

/* Turn info: only visible when panel is active */

.turn-info {
  display: none;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  margin-top: 4px;
}

.player-panel.active .turn-info {
  display: flex;
}

.turn-label {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #e07b39;
}

.resign-btn {
  padding: 5px 10px;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.5);
  background: rgba(220, 53, 69, 0.1);
  border: 1px solid rgba(220, 53, 69, 0.3);
  border-radius: 6px;
  cursor: pointer;
  transition: color 0.15s, background 0.15s, border-color 0.15s;
}

.resign-btn:hover {
  color: #fff;
  background: rgba(220, 53, 69, 0.3);
  border-color: rgba(220, 53, 69, 0.6);
}

/* ── Win banner ── */

#win-banner {
  padding: 10px 16px;
  background: linear-gradient(135deg, rgba(224,123,57,0.18), rgba(192,82,42,0.12));
  border: 1px solid rgba(224, 123, 57, 0.4);
  border-radius: 8px;
  text-align: center;
}

#win-text {
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: #e07b39;
}

/* ── Game actions ── */

.game-actions {
  display: flex;
  gap: 12px;
  width: 100%;
}

#back-btn {
  padding: 10px 20px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.5);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 8px;
  cursor: pointer;
  transition: color 0.15s, background 0.15s;
}

#back-btn:hover {
  color: #fff;
  background: rgba(255, 255, 255, 0.1);
}

/* ── Board ── */

#board {
  border-collapse: collapse;
  border-radius: 8px;
  overflow: hidden;
  box-shadow:
    0 0 0 4px #4a3728,
    0 0 0 8px #2c1f15,
    0 8px 40px rgba(0, 0, 0, 0.7);
  cursor: pointer;
}

tr td {
  width: 68px;
  height: 68px;
  padding: 0;
  transition: background-color 0.15s ease;
}

/* dark squares */
tr:nth-child(n) td:nth-child(n + 1) {
  background: #3b2314;
}

/* light squares */
tr:nth-child(2n) td:nth-child(2n + 1),
tr:nth-child(2n + 1) td:nth-child(2n) {
  background: #c8a97e;
}

/* ── Pieces ── */

#peca, #dama {
  cursor: pointer;
  width: 80%;
  height: 80%;
  margin: 10%;
  border-radius: 50%;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

#peca.black, #dama.black {
  background: radial-gradient(circle at 35% 35%, #555, #111);
  box-shadow:
    inset 0 -3px 6px rgba(255,255,255,0.1),
    inset 0 2px 4px rgba(255,255,255,0.15),
    0 4px 10px rgba(0,0,0,0.6);
  border: 2px solid #000;
}

#peca.white, #dama.white {
  background: radial-gradient(circle at 35% 35%, #fff, #c0c0c0);
  box-shadow:
    inset 0 -3px 6px rgba(0,0,0,0.15),
    inset 0 2px 4px rgba(255,255,255,0.8),
    0 4px 10px rgba(0,0,0,0.4);
  border: 2px solid #aaa;
}

#peca:hover, #dama:hover {
  transform: scale(1.08);
  box-shadow:
    0 6px 16px rgba(0,0,0,0.5),
    0 0 0 3px rgba(255,255,255,0.3);
}

#dama {
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 26px;
}

/* ── Highlighted squares ── */

table tr td.verde {
  background-color: rgba(72, 199, 116, 0.55) !important;
  box-shadow: inset 0 0 0 3px rgba(72, 199, 116, 0.8);
}

table tr td.amarelo {
  background-color: rgba(255, 214, 0, 0.55) !important;
  box-shadow: inset 0 0 0 3px rgba(255, 214, 0, 0.8);
}

table tr td.vermelho {
  background-color: rgba(220, 53, 69, 0.55) !important;
  box-shadow: inset 0 0 0 3px rgba(220, 53, 69, 0.8);
}

/* ── Start button ── */

#generate {
  cursor: pointer;
  padding: 12px 36px;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #fff;
  background: linear-gradient(135deg, #e07b39, #c0522a);
  border: none;
  border-radius: 8px;
  box-shadow: 0 4px 16px rgba(192, 82, 42, 0.45);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

#generate:hover {
  background: linear-gradient(135deg, #f08c4a, #d0623a);
  transform: translateY(-2px);
  box-shadow: 0 6px 22px rgba(192, 82, 42, 0.55);
}

#generate:active {
  transform: translateY(0);
  box-shadow: 0 2px 8px rgba(192, 82, 42, 0.4);
}

/* ── Misc ── */

h1, h2, h3, h6 {
  margin: 0;
  color: #fff;
}

#controle {
  background: rgba(255, 255, 255, 0.06);
  padding: 8px 12px;
  border-radius: 8px;
  display: flex;
  justify-content: flex-end;
  margin-bottom: 12px;
  gap: 8px;
  backdrop-filter: blur(4px);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.box {
  display: flex;
  flex-direction: column;
  padding: 1%;
}

@media (max-width: 720px) {
  body, html {
    min-height: 100%;
  }

  body {
    display: block;
    --sidebar-mobile-width: min(82vw, 300px);
  }

  .sidebar-toggle {
    position: fixed;
    top: 12px;
    left: 12px;
    z-index: 40;
    width: 42px;
    height: 42px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    background: rgba(18, 18, 42, 0.92);
    border: 1px solid rgba(255, 255, 255, 0.12);
    border-radius: 8px;
    font-family: Arial, sans-serif;
    font-size: 24px;
    font-weight: 700;
    line-height: 1;
    cursor: pointer;
    box-shadow: 0 4px 18px rgba(0, 0, 0, 0.35);
  }

  body.sidebar-open .sidebar-toggle {
    left: calc(var(--sidebar-mobile-width) - 54px);
    background: rgba(18, 18, 42, 0.98);
  }

  .sidebar-backdrop {
    position: fixed;
    inset: 0;
    z-index: 20;
    display: block;
    background: rgba(0, 0, 0, 0.55);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.18s ease;
  }

  .sidebar {
    position: fixed;
    inset: 0 auto 0 0;
    z-index: 30;
    width: var(--sidebar-mobile-width);
    min-width: 0;
    transform: translateX(-100%);
    visibility: hidden;
    pointer-events: none;
    transition: transform 0.18s ease;
    box-shadow: 12px 0 28px rgba(0, 0, 0, 0.35);
  }

  body.sidebar-open .sidebar {
    transform: translateX(0);
    visibility: visible;
    pointer-events: auto;
  }

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

  .game {
    min-height: 100%;
    align-items: stretch;
    justify-content: flex-start;
    gap: 12px;
    padding: 64px 12px 12px;
  }

  #menu {
    max-width: none;
    gap: 20px;
  }

  .menu-title {
    font-size: clamp(36px, 11vw, 48px);
  }

  .mode-cards,
  .version-options,
  .difficulty-options,
  .player-inputs {
    gap: 10px;
  }

  #game-container {
    align-items: stretch;
    gap: 12px;
    width: 100%;
    min-height: 100%;
  }

  .board-wrapper {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    grid-template-areas:
      "white black"
      "board board";
    align-items: stretch;
    gap: 10px;
    width: 100%;
  }

  #panel-white {
    grid-area: white;
  }

  #panel-black {
    grid-area: black;
  }

  .board-area {
    grid-area: board;
    align-items: center;
    width: 100%;
  }

  .player-panel {
    width: auto;
    min-width: 0;
    min-height: 76px;
    flex-direction: row;
    justify-content: space-between;
    gap: 8px;
    padding: 10px;
    border-radius: 10px;
  }

  .panel-piece {
    flex: 0 0 auto;
    font-size: 20px;
  }

  .panel-name {
    min-width: 0;
    flex: 1 1 auto;
    overflow: hidden;
    text-align: left;
    text-overflow: ellipsis;
    white-space: nowrap;
    word-break: normal;
  }

  .panel-score {
    flex: 0 0 auto;
    font-size: 30px;
  }

  .turn-info {
    flex: 0 0 auto;
    align-items: flex-end;
    gap: 4px;
    margin-top: 0;
  }

  .turn-label {
    font-size: 9px;
    white-space: nowrap;
  }

  .resign-btn {
    padding: 4px 8px;
    font-size: 9px;
  }

  #board {
    --board-size: clamp(220px, min(calc(100vw - 24px), calc(100vh - 240px)), 560px);
    width: var(--board-size);
    height: var(--board-size);
    table-layout: fixed;
  }

  #board tr {
    height: 12.5%;
  }

  tr td {
    width: 12.5%;
    height: 12.5%;
  }

  #peca, #dama {
    border-width: 1px;
  }

  #dama {
    font-size: clamp(14px, 5vw, 22px);
  }

  .game-actions {
    gap: 10px;
  }

  #back-btn,
  #generate {
    flex: 1;
    min-width: 0;
    padding: 12px 10px;
    font-size: clamp(11px, 3.2vw, 14px);
  }
}

@media (max-width: 420px) {
  .game {
    padding: 62px 10px 10px;
  }

  .mode-cards,
  .version-options,
  .difficulty-options,
  .player-inputs,
  .game-actions {
    flex-direction: column;
  }

  .player-panel {
    min-height: 64px;
    padding: 8px;
  }

  .panel-piece {
    display: none;
  }

  .panel-score {
    font-size: 26px;
  }

  #board {
    --board-size: clamp(180px, min(calc(100vw - 20px), calc(100vh - 220px)), 420px);
  }
}