/* ============================================================
   style.css — 化学合成游戏 ChemCraft
   风格：实验室 + 草稿纸 / 黑板 + 科研感
   ============================================================ */

/* ---- CSS 变量 ---- */
:root {
  --bg:            #f5f1ea;
  --surface:       #ffffff;
  --surface-alt:   #ece6da;
  --sidebar-bg:    #e8e2d5;
  --sidebar-border:#d5cfc2;
  --text:          #2c3e50;
  --text-light:    #7f8c8d;
  --accent:        #2c5f8a;
  --accent-light:  #457b9d;
  --danger:        #c0392b;
  --success:       #27ae60;
  --warning:       #f39c12;
  --shadow:        0 2px 8px rgba(0,0,0,0.08);
  --shadow-lg:     0 4px 20px rgba(0,0,0,0.12);
  --radius:        8px;
  --radius-sm:     4px;
  --sidebar-w:     260px;
  --header-h:      56px;

  /* 黑板色 */
  --blackboard:    #2c3e50;
}

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

html, body {
  height: 100%;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", sans-serif;
  font-size: 14px;
  color: var(--text);
  background: var(--bg);
  overflow: hidden;
  user-select: none;
  -webkit-user-select: none;
}

/* ---- App 布局 ---- */
.app {
  display: flex;
  height: 100vh;
  width: 100vw;
}

/* ---- 侧栏 ---- */
.sidebar {
  width: var(--sidebar-w);
  min-width: var(--sidebar-w);
  background: var(--sidebar-bg);
  border-right: 1px solid var(--sidebar-border);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  z-index: 10;
  box-shadow: var(--shadow);
}

.sidebar-header {
  padding: 16px 16px 12px;
  border-bottom: 1px solid var(--sidebar-border);
}

.sidebar-header h2 {
  font-size: 18px;
  color: var(--accent);
  font-weight: 700;
  letter-spacing: -0.3px;
}

.sidebar-header .subtitle {
  font-size: 11px;
  color: var(--text-light);
  margin-top: 2px;
}

.sidebar-section {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-height: 0;
  overflow: hidden;
}

.sidebar-section + .sidebar-section {
  border-top: 1px solid var(--sidebar-border);
}

.section-title {
  padding: 10px 16px 6px;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-light);
}

/* 元素列表 */
.element-list {
  flex: 1;
  overflow-y: auto;
  padding: 4px 8px 8px;
  display: flex;
  flex-wrap: wrap;
  align-content: flex-start;
  gap: 6px;
}

.element-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 68px;
  padding: 8px 4px 6px;
  border-radius: var(--radius);
  cursor: grab;
  transition: all 0.15s ease;
  background: var(--surface);
  border: 1px solid transparent;
  position: relative;
}

.element-item:hover {
  background: #faf7f0;
  border-color: var(--accent-light);
  box-shadow: 0 2px 8px rgba(44,95,138,0.15);
  transform: translateY(-1px);
}

.element-item:active {
  cursor: grabbing;
  transform: scale(0.95);
}

.element-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.element-icon img {
  width: 44px;
  height: 44px;
}

.element-label {
  font-size: 13px;
  font-weight: 700;
  color: var(--text);
  margin-top: 2px;
}

.element-info {
  font-size: 9px;
  color: var(--text-light);
  text-align: center;
  line-height: 1.2;
}

/* 已发现物质 */
.discovered-list {
  flex: 1;
  overflow-y: auto;
  padding: 4px 8px 8px;
}

.discovered-empty {
  padding: 16px;
  text-align: center;
  color: var(--text-light);
  font-size: 12px;
  font-style: italic;
}

.discovered-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 10px;
  margin-bottom: 4px;
  background: var(--surface);
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  transition: all 0.15s;
}

.discovered-item:hover {
  border-color: var(--accent-light);
  box-shadow: 0 1px 4px rgba(0,0,0,0.06);
}

.discovered-formula {
  font-size: 13px;
  font-weight: 600;
  color: var(--accent);
  font-family: 'Times New Roman', Georgia, serif;
  display: flex;
  align-items: center;
}

.discovered-formula sub {
  font-size: 0.7em;
}

.discovered-actions {
  display: flex;
  gap: 4px;
}

.discovered-actions .btn-sm {
  padding: 2px 8px;
  font-size: 11px;
  border-radius: 3px;
  border: 1px solid #ccc;
  background: #f8f8f8;
  cursor: pointer;
  transition: all 0.15s;
}

.discovered-actions .btn-sm:hover {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.discovered-actions .btn-danger:hover {
  background: var(--danger);
  border-color: var(--danger);
}

/* ---- 主工作区 ---- */
.workspace {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
  background:
    /* 网格线 */
    linear-gradient(rgba(0,0,0,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0,0,0,0.03) 1px, transparent 1px),
    var(--surface);
  background-size: 40px 40px;
  background-position: -1px -1px;
}

/* 顶部工具栏 */
.workspace-header {
  height: var(--header-h);
  min-height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px;
  background: var(--blackboard);
  color: #ecf0f1;
  box-shadow: 0 2px 8px rgba(0,0,0,0.2);
  z-index: 5;
}

.formula-display {
  flex: 1;
  font-size: 16px;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
  overflow: hidden;
}

.formula-label {
  color: #bdc3c7;
  font-size: 13px;
}

.formula-badge {
  display: inline-flex;
  align-items: center;
  background: rgba(255,255,255,0.12);
  padding: 4px 12px;
  border-radius: 14px;
  font-family: 'Times New Roman', Georgia, serif;
  font-weight: 700;
  font-size: 15px;
  color: #f1c40f;
  letter-spacing: 1px;
}

.formula-empty {
  color: #95a5a6;
  font-style: italic;
  font-size: 13px;
}

.toolbar {
  display: flex;
  gap: 8px;
  flex-shrink: 0;
}

.btn {
  padding: 7px 16px;
  font-size: 13px;
  font-weight: 600;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.15s;
  white-space: nowrap;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--accent-light);
  transform: translateY(-1px);
  box-shadow: 0 2px 6px rgba(0,0,0,0.2);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-outline {
  background: transparent;
  color: #ecf0f1;
  border: 1px solid rgba(255,255,255,0.3);
}

.btn-outline:hover {
  background: rgba(255,255,255,0.1);
  border-color: rgba(255,255,255,0.6);
}

.btn-danger {
  background: var(--danger);
  color: #fff;
}

.btn-danger:hover {
  background: #e74c3c;
}

/* 画布容器 */
.canvas-container {
  flex: 1;
  position: relative;
  overflow: hidden;
  cursor: crosshair;
}

.canvas-container.dragging {
  cursor: grabbing;
}

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

/* 拖拽幽灵 */
.drag-ghost {
  pointer-events: none;
  z-index: 1000;
  filter: drop-shadow(0 4px 8px rgba(0,0,0,0.3));
}

/* 提示浮层 */
.tooltip {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--blackboard);
  color: #ecf0f1;
  padding: 10px 24px;
  border-radius: 20px;
  font-size: 13px;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.3s;
  z-index: 100;
}

.tooltip.show {
  opacity: 0.95;
}

/* ---- SVG 交互样式 ---- */
.atom-group {
  cursor: grab;
  transition: filter 0.15s;
}

.atom-group:hover .atom-circle {
  filter: brightness(1.15);
}

.atom-group:active {
  cursor: grabbing;
}

.bond-group {
  cursor: pointer;
}

.bond-group line:not(.bond-hit-area) {
  transition: stroke 0.15s;
}

.bond-group:hover line:not(.bond-hit-area) {
  stroke: var(--accent) !important;
}

/* ---- 框选矩形 ---- */
#selection-box {
  pointer-events: none;
}

/* ---- 画布状态光标 ---- */
#canvas-svg[style*="cursor: grab"] {
  cursor: grab;
}

/* ---- 响应式 ---- */
@media (max-width: 768px) {
  .app {
    flex-direction: column;
  }

  .sidebar {
    width: 100%;
    min-width: 100%;
    max-height: 160px;
    flex-shrink: 0;
    flex-direction: row;
    border-right: none;
    border-bottom: 1px solid var(--sidebar-border);
  }

  .sidebar-header {
    display: none;
  }

  .sidebar-section {
    flex-direction: column;
    min-width: 0;
  }

  .element-list {
    flex-wrap: nowrap;
    overflow-x: auto;
    padding: 4px 8px;
  }

  .element-item {
    width: 56px;
    min-width: 56px;
    padding: 6px 2px 4px;
  }

  .element-icon img {
    width: 36px;
    height: 36px;
  }

  .element-label {
    font-size: 10px;
  }

  .element-info {
    display: none;
  }

  .discovered-list {
    flex-wrap: nowrap;
    overflow-x: auto;
  }

  .workspace {
    flex: 1;
  }

  .workspace-header {
    height: 44px;
    min-height: 44px;
    padding: 0 12px;
  }

  .formula-display {
    font-size: 13px;
  }

  .formula-badge {
    font-size: 12px;
    padding: 3px 8px;
  }

  .btn {
    padding: 5px 10px;
    font-size: 11px;
  }
}

@media (max-width: 480px) {
  .sidebar {
    max-height: 120px;
  }

  .element-item {
    width: 44px;
    min-width: 44px;
    padding: 4px 1px 2px;
  }

  .element-icon img {
    width: 28px;
    height: 28px;
  }

  .element-label {
    font-size: 9px;
  }

  .btn {
    padding: 4px 8px;
    font-size: 10px;
  }

  .formula-display {
    font-size: 11px;
  }

  .section-title {
    font-size: 9px;
    padding: 6px 8px 2px;
  }
}