/* ========================================
   CSS Variables - 清新純色配色
   ======================================== */
:root {
  /* 主色調 */
  --color-primary: #4A90A4;
  --color-primary-hover: #3A7A8E;
  --color-primary-active: #2D6270;

  /* 次要色 */
  --color-secondary: #6B7280;
  --color-secondary-hover: #5B626F;
  --color-secondary-active: #4B525F;

  /* 成功/錯誤 */
  --color-success: #10B981;
  --color-danger: #EF4444;

  /* 背景色 */
  --color-bg: #F8FAFC;
  --color-bg-card: #FFFFFF;
  --color-bg-input: #FFFFFF;

  /* 文字色 */
  --color-text: #1F2937;
  --color-text-light: #6B7280;
  --color-text-inverse: #FFFFFF;

  /* 邊框色 */
  --color-border: #E5E7EB;
  --color-border-focus: #4A90A4;

  /* 圓角 */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-full: 50%;

  /* 間距 */
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;

  /* 字體大小 */
  --font-size-sm: 14px;
  --font-size-md: 16px;
  --font-size-lg: 18px;
  --font-size-xl: 24px;

  /* 陰影 */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
}

/* ========================================
   Reset & Base
   ======================================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-tap-highlight-color: transparent;
  /* 禁止雙擊縮放 */
  touch-action: manipulation;
  height: 100%;
  overflow: hidden;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.5;
  height: 100%;
  overflow: hidden;
  /* 禁止拖曳和選取 */
  touch-action: manipulation;
  -webkit-user-select: none;
  user-select: none;
  overscroll-behavior: none;
}

/* 允許輸入框選取文字 */
input, textarea {
  -webkit-user-select: text;
  user-select: text;
}

/* ========================================
   Screen Container
   ======================================== */
.screen {
  display: none;
  padding: var(--spacing-md);
  max-width: 480px;
  margin: 0 auto;
  height: 100%;
  overflow: hidden;
  box-sizing: border-box;
}

.screen.active {
  display: flex;
  flex-direction: column;
}

.app-title {
  font-size: var(--font-size-xl);
  text-align: center;
  margin-bottom: var(--spacing-lg);
  color: var(--color-primary);
}

.screen-title {
  font-size: var(--font-size-lg);
  text-align: center;
  margin-bottom: var(--spacing-md);
}

/* ========================================
   Tab Navigation
   ======================================== */
.tab-container {
  display: flex;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
}

.tab-btn {
  flex: 1;
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: var(--font-size-md);
  border: 2px solid var(--color-border);
  background-color: var(--color-bg-card);
  color: var(--color-text-light);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.2s ease;
}

.tab-btn.active {
  border-color: var(--color-primary);
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
}

.tab-panel {
  display: none;
}

.tab-panel.active {
  display: block;
}

/* ========================================
   Form Elements
   ======================================== */
.form-group {
  margin-bottom: var(--spacing-md);
}

.form-group label {
  display: block;
  font-size: var(--font-size-sm);
  color: var(--color-text-light);
  margin-bottom: var(--spacing-xs);
}

.input {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: var(--font-size-md);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  background-color: var(--color-bg-input);
  color: var(--color-text);
  transition: border-color 0.2s ease;
}

.input:focus {
  outline: none;
  border-color: var(--color-border-focus);
}

.input::placeholder {
  color: var(--color-text-light);
}

select.input {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%236B7280' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 36px;
}

/* ========================================
   Buttons
   ======================================== */
.btn {
  display: inline-block;
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-lg);
  font-size: var(--font-size-md);
  font-weight: 500;
  text-align: center;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background-color 0.2s ease;
}

.btn-primary {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
}

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

.btn-primary:active {
  background-color: var(--color-primary-active);
}

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

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

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

.btn-success {
  background-color: var(--color-success);
  color: var(--color-text-inverse);
}

.btn-danger {
  background-color: var(--color-danger);
  color: var(--color-text-inverse);
}

.btn-small {
  width: auto;
  padding: var(--spacing-xs) var(--spacing-md);
  font-size: var(--font-size-sm);
}

/* ========================================
   Code Display (認證碼顯示)
   ======================================== */
.code-display {
  display: flex;
  justify-content: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-sm);
  cursor: pointer;
}

#create-code-display,
#join-code-display {
  padding: var(--spacing-sm);
  border-radius: var(--radius-md);
  transition: background-color 0.2s ease;
}

#create-code-display:hover,
#join-code-display:hover {
  background-color: var(--color-border);
}

.code-box {
  width: 44px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-xl);
  font-weight: 600;
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  background-color: var(--color-bg-card);
  color: var(--color-text);
}

.code-box.filled {
  border-color: var(--color-primary);
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
}

/* ========================================
   Numpad Overlay (數字鍵盤彈出層)
   ======================================== */
.numpad-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 1000;
  justify-content: center;
  align-items: center;
}

.numpad-overlay.active {
  display: flex;
}

.numpad-modal {
  background-color: var(--color-bg-card);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-md);
  max-width: 90vw;
}

.numpad-header {
  text-align: center;
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
}

#numpad-code-display {
  cursor: default;
  margin-bottom: var(--spacing-md);
}

#numpad-code-display:hover {
  background-color: transparent;
}

/* ========================================
   Numpad (數字鍵盤)
   ======================================== */
.numpad {
  padding: var(--spacing-md);
  background-color: var(--color-bg-card);
  border-radius: var(--radius-lg);
}

.numpad-row {
  display: flex;
  justify-content: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-sm);
}

.numpad-row:last-child {
  margin-bottom: 0;
}

.numpad-btn {
  width: 72px;
  height: 56px;
  font-size: var(--font-size-xl);
  font-weight: 500;
  border: none;
  border-radius: var(--radius-md);
  background-color: var(--color-bg);
  color: var(--color-text);
  cursor: pointer;
  transition: background-color 0.15s ease;
}

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

.numpad-btn:active {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
}

.numpad-empty {
  visibility: hidden;
}

.numpad-backspace {
  font-size: var(--font-size-lg);
}

/* ========================================
   Waiting Screen (等待連線畫面)
   ======================================== */
.room-info {
  background-color: var(--color-bg-card);
  padding: var(--spacing-md);
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-md);
  box-shadow: var(--shadow-sm);
}

.room-info p {
  margin-bottom: var(--spacing-xs);
}

.room-info p:last-child {
  margin-bottom: 0;
}

.room-name span,
.room-code span {
  font-weight: 600;
  color: var(--color-primary);
}

.player-list,
.pending-requests {
  background-color: var(--color-bg-card);
  padding: var(--spacing-md);
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-md);
  box-shadow: var(--shadow-sm);
}

.player-list h3,
.pending-requests h3 {
  font-size: var(--font-size-md);
  margin-bottom: var(--spacing-sm);
}

.player-list ul,
.pending-requests ul {
  list-style: none;
}

.player-list li,
.pending-requests li {
  padding: var(--spacing-sm);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.player-list li:last-child,
.pending-requests li:last-child {
  border-bottom: none;
}

.pending-requests .request-actions {
  display: flex;
  gap: var(--spacing-xs);
}

.hidden {
  display: none !important;
}

/* ========================================
   Game Screen (遊戲畫面)
   ======================================== */
.game-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-md);
}

.game-header .screen-title {
  margin-bottom: 0;
}

.game-players {
  background-color: var(--color-bg-card);
  padding: var(--spacing-md);
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-md);
  box-shadow: var(--shadow-sm);
}

.game-players h3 {
  font-size: var(--font-size-md);
  margin-bottom: var(--spacing-sm);
}

.player-avatars {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.player-avatar {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-text-inverse);
}

/* ========================================
   Chat (聊天介面)
   ======================================== */
.chat-container {
  background-color: var(--color-bg-card);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  height: 400px;
}

.chat-messages {
  flex: 1;
  overflow-y: auto;
  padding: var(--spacing-md);
}

.chat-message {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-sm);
}

.chat-message:last-child {
  margin-bottom: 0;
}

.chat-message .avatar {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-inverse);
  flex-shrink: 0;
}

.chat-message .content {
  flex: 1;
}

.chat-message .sender {
  font-size: var(--font-size-sm);
  font-weight: 600;
  margin-bottom: 2px;
}

.chat-message .text {
  font-size: var(--font-size-md);
  word-break: break-word;
}

/* 系統訊息樣式 */
.chat-message.system {
  justify-content: center;
}

.chat-message.system .text {
  font-size: var(--font-size-sm);
  color: var(--color-text-light);
  font-style: italic;
}

.chat-input-container {
  display: flex;
  gap: var(--spacing-sm);
  padding: var(--spacing-md);
  border-top: 1px solid var(--color-border);
}

.chat-input-container .input {
  flex: 1;
}

.chat-input-container .btn {
  width: auto;
  flex-shrink: 0;
}

/* ========================================
   Responsive (RWD)
   ======================================== */
@media (min-width: 768px) {
  .screen {
    padding: var(--spacing-xl);
  }

  .code-box {
    width: 52px;
    height: 60px;
  }

  .numpad-btn {
    width: 80px;
    height: 64px;
  }

  .chat-container {
    height: 500px;
  }
}

/* ========================================
   連線狀態指示器
   ======================================== */
.connection-status {
  position: fixed;
  top: 8px;
  right: 8px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  z-index: 1000;
  transition: background-color 0.3s ease;
}

.connection-status.connected {
  background-color: var(--color-success);
}

.connection-status.reconnecting {
  background-color: #FFA500;
  animation: pulse 1s ease-in-out infinite;
}

.connection-status.disconnected {
  background-color: var(--color-danger);
}

@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.4;
  }
}