:root {
  --bg-main: #0b0f19;
  --bg-card: #151d30;
  --bg-card-hover: #1e2942;
  --border-color: #263554;
  --text-main: #f1f5f9;
  --text-muted: #94a3b8;
  
  --color-primary: #38bdf8;
  --color-primary-hover: #0ea5e9;
  
  --color-white-player: #f8fafc;
  --color-black-player: #475569;
  --color-accent: #f59e0b; /* Yellow for highlights */
  --color-success: #10b981; /* Green for moves */
  --color-danger: #ef4444; /* Red for captures/checks */
}

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

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background-color: var(--bg-main);
  color: var(--text-main);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

.hidden {
  display: none !important;
}

/* ============================================================
   LOBBY OVERLAY
   ============================================================ */
#lobby-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 100;
  background: radial-gradient(circle at center, #111827 0%, #030712 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.lobby-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  width: 100%;
  max-width: 500px;
  padding: 40px 30px;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
  display: flex;
  flex-direction: column;
}

.logo {
  text-align: center;
  font-size: 2.5rem;
  font-weight: 800;
  letter-spacing: 0.15em;
  color: var(--color-primary);
  margin-bottom: 30px;
  text-shadow: 0 0 15px rgba(56, 189, 248, 0.4);
}

.form-section h3 {
  font-size: 1.1rem;
  color: var(--text-muted);
  margin-bottom: 15px;
}

.input-group {
  display: flex;
  gap: 10px;
  margin-bottom: 20px;
}

input[type="text"] {
  flex: 1;
  background-color: var(--bg-main);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  padding: 12px 16px;
  border-radius: 8px;
  font-size: 1rem;
  outline: none;
  transition: border-color 0.2s;
}

input[type="text"]:focus {
  border-color: var(--color-primary);
}

button {
  background-color: var(--color-primary);
  color: #0f172a;
  border: none;
  padding: 12px 24px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: background-color 0.2s, transform 0.1s;
}

button:hover {
  background-color: var(--color-primary-hover);
}

button:active {
  transform: scale(0.98);
}

button:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  transform: none;
}

.welcome-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 25px;
  padding-bottom: 15px;
  border-bottom: 1px solid var(--border-color);
  font-size: 1rem;
}

.text-btn {
  background: none;
  color: var(--color-primary);
  padding: 0;
  border-radius: 0;
  font-size: 0.9rem;
}
.text-btn:hover {
  background: none;
  text-decoration: underline;
  color: var(--color-primary-hover);
}

.create-room-box {
  background-color: rgba(255,255,255,0.02);
  border: 1px dashed var(--border-color);
  padding: 15px;
  border-radius: 10px;
  margin-bottom: 25px;
}

.rooms-list-container {
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.rooms-list {
  max-height: 250px;
  overflow-y: auto;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  background-color: var(--bg-main);
}

.no-rooms {
  text-align: center;
  padding: 30px 20px;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.room-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 18px;
  border-bottom: 1px solid var(--border-color);
  transition: background-color 0.15s;
}

.room-item:last-child {
  border-bottom: none;
}

.room-item:hover {
  background-color: var(--bg-card-hover);
}

.room-info {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.room-name {
  font-weight: 600;
  font-size: 1rem;
}

.room-players {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.join-btn {
  padding: 8px 16px;
  font-size: 0.9rem;
}

/* ============================================================
   GAME SCREEN
   ============================================================ */
#game-container {
  width: 100%;
  height: 100%;
  display: grid;
  grid-template-columns: 1fr 380px;
}

#canvas-container {
  position: relative;
  width: 100%;
  height: 100%;
}

#canvas-container canvas {
  display: block;
  width: 100%;
  height: 100%;
}

#hint {
  position: absolute;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  color: #a1a1aa;
  font-size: 0.85rem;
  background: rgba(15, 23, 42, 0.8);
  backdrop-filter: blur(4px);
  padding: 8px 16px;
  border-radius: 20px;
  border: 1px solid var(--border-color);
  pointer-events: none;
  text-align: center;
  white-space: nowrap;
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.3);
}

/* ============================================================
   SIDEBAR
   ============================================================ */
#sidebar {
  background-color: var(--bg-card);
  border-left: 1px solid var(--border-color);
  height: 100%;
  display: flex;
  flex-direction: column;
  padding: 20px;
  gap: 20px;
  overflow: hidden;
}

.sidebar-card {
  background-color: var(--bg-main);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 16px;
  display: flex;
  flex-direction: column;
}

.fill-remaining {
  flex-grow: 1;
  overflow: hidden;
}

.game-meta-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 8px;
}

#room-title {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--color-primary);
  max-width: 200px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.leave-btn {
  background-color: #ef4444;
  color: #fff;
  padding: 6px 12px;
  font-size: 0.85rem;
  border-radius: 6px;
}
.leave-btn:hover {
  background-color: #dc2626;
}

#turn-indicator {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 4px;
}

#status-message {
  font-size: 0.9rem;
  color: var(--color-accent);
  min-height: 1.3em;
  margin-bottom: 12px;
}

.players-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 16px;
}

.player-slot {
  display: flex;
  align-items: center;
  padding: 10px 12px;
  border-radius: 8px;
  background-color: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border-color);
  gap: 12px;
}

.color-badge {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  border: 1px solid #fff;
}
.color-badge.white {
  background-color: #fff;
}
.color-badge.black {
  background-color: #000;
  border-color: #555;
}

.player-name {
  font-weight: 600;
  font-size: 0.95rem;
  flex-grow: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.player-status {
  font-size: 0.8rem;
  color: var(--color-success);
}

.game-actions button {
  width: 100%;
  padding: 10px;
  font-size: 0.95rem;
}

.spectators-section {
  margin-bottom: 16px;
  background-color: rgba(255, 255, 255, 0.01);
  border: 1px solid var(--border-color);
  padding: 8px 12px;
  border-radius: 8px;
}

.spectators-section h4 {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 4px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

#spectators-list {
  font-size: 0.9rem;
  color: var(--text-main);
  overflow-wrap: break-word;
}

/* ============================================================
   CHAT SECTION
   ============================================================ */
#chat-card h3 {
  font-size: 1rem;
  margin-bottom: 10px;
  color: var(--text-muted);
}

#chat-messages {
  flex-grow: 1;
  overflow-y: auto;
  background-color: var(--bg-main);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 10px;
}

.chat-msg {
  font-size: 0.9rem;
  line-height: 1.4;
  word-break: break-word;
}

.chat-msg.system {
  color: var(--color-accent);
  font-style: italic;
  font-size: 0.85rem;
  border-left: 2px solid var(--color-accent);
  padding-left: 6px;
}

.chat-msg.alert {
  color: var(--color-danger);
  font-weight: bold;
  font-size: 0.85rem;
}

.msg-time {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-right: 6px;
}

.msg-user {
  font-weight: 700;
  color: var(--color-primary);
  margin-right: 4px;
}

#chat-form {
  display: flex;
  gap: 8px;
}

#chat-input {
  flex-grow: 1;
  padding: 10px;
  font-size: 0.9rem;
  border-radius: 6px;
}

#send-chat-btn {
  padding: 10px 16px;
  font-size: 0.9rem;
  border-radius: 6px;
}

/* ============================================================
   LOADER OVERLAY
   ============================================================ */
#loader-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(15, 23, 42, 0.95);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
}

.loader-content {
  text-align: center;
}

.spinner {
  width: 50px;
  height: 50px;
  border: 4px solid var(--border-color);
  border-top: 4px solid var(--color-primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin: 0 auto 20px;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

#loader-text {
  font-size: 1.1rem;
  font-weight: 500;
}

/* ============================================================
   RESPONSIVENESS
   ============================================================ */
@media (max-width: 900px) {
  #game-container {
    grid-template-columns: 1fr;
    grid-template-rows: 1fr 340px;
  }
  
  #sidebar {
    border-left: none;
    border-top: 1px solid var(--border-color);
    padding: 12px;
    gap: 12px;
    flex-direction: row;
  }

  .sidebar-card {
    flex: 1;
    height: 100%;
  }
  
  #hud-card {
    max-width: 300px;
  }

  #hint {
    bottom: 10px;
    font-size: 0.75rem;
    padding: 6px 12px;
  }
}

@media (max-width: 600px) {
  #sidebar {
    flex-direction: column;
    height: 380px;
  }

  #game-container {
    grid-template-rows: 1fr 380px;
  }

  #hud-card {
    max-width: none;
    height: auto;
  }
}

@media (max-width: 480px) {
  .lobby-card {
    padding: 30px 20px;
  }
  .input-group {
    flex-direction: column;
    gap: 12px;
  }
  .input-group input[type="text"],
  .input-group button {
    width: 100%;
  }
}