/* ============================================
   证件照工具 - 全局样式系统
   设计方向：专业蓝 + 干净利落 + 细节打磨
   ============================================ */

/* --- Google Fonts 在HTML中引入 --- */

/* === CSS Variables === */
:root {
  /* 主色 */
  --c-primary: #2563EB;
  --c-primary-hover: #1D4ED8;
  --c-primary-light: #EFF6FF;
  --c-primary-pale: #DBEAFE;
  --c-primary-glow: rgba(37, 99, 235, 0.12);

  /* 辅助色 */
  --c-accent: #F59E0B;
  --c-accent-hover: #D97706;
  --c-success: #10B981;
  --c-danger: #EF4444;

  /* 中性色 */
  --c-bg: #F1F5F9;
  --c-bg-card: #FFFFFF;
  --c-bg-elevated: #FFFFFF;
  --c-border: #E2E8F0;
  --c-border-light: #F1F5F9;
  --c-text: #0F172A;
  --c-text-secondary: #475569;
  --c-text-muted: #94A3B8;
  --c-text-inverse: #FFFFFF;

  /* 圆角 */
  --r-sm: 6px;
  --r-md: 10px;
  --r-lg: 14px;
  --r-xl: 20px;
  --r-full: 9999px;

  /* 阴影 */
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.06);
  --shadow-lg: 0 8px 30px rgba(0,0,0,0.08);
  --shadow-xl: 0 12px 40px rgba(0,0,0,0.12);
  --shadow-primary: 0 4px 14px rgba(37, 99, 235, 0.25);

  /* 字体 */
  --font-body: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-display: 'Noto Sans SC', sans-serif;

  /* 动画 */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --duration-fast: 0.15s;
  --duration-normal: 0.25s;
  --duration-slow: 0.4s;

  /* 布局 */
  --max-width: 1200px;
  --nav-height: 64px;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  color: var(--c-text);
  background: var(--c-bg);
  line-height: 1.6;
  min-height: 100vh;
}

a {
  color: var(--c-primary);
  text-decoration: none;
  transition: color var(--duration-fast);
}
a:hover {
  color: var(--c-primary-hover);
}

img {
  max-width: 100%;
  display: block;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  outline: none;
}

input, select {
  font-family: inherit;
}

/* === 通用容器 === */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* === 导航栏 === */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--c-border);
  height: var(--nav-height);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--c-text);
  text-decoration: none;
}

.nav-logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--c-primary) 0%, #3B82F6 100%);
  border-radius: var(--r-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 1.1rem;
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.3);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
  list-style: none;
}

.nav-links a {
  color: var(--c-text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  padding: 8px 14px;
  border-radius: var(--r-full);
  transition: all var(--duration-fast);
}

.nav-links a:hover {
  color: var(--c-primary);
  background: var(--c-primary-light);
}

.nav-links a.active {
  color: var(--c-primary);
  background: var(--c-primary-light);
}

/* 移动端汉堡菜单 */
.nav-toggle {
  display: none;
  background: none;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  border-radius: var(--r-md);
}

.nav-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--c-text);
  position: relative;
  transition: background var(--duration-fast);
}

.nav-toggle span::before,
.nav-toggle span::after {
  content: '';
  display: block;
  width: 20px;
  height: 2px;
  background: var(--c-text);
  position: absolute;
  left: 0;
  transition: transform var(--duration-normal) var(--ease-out);
}
.nav-toggle span::before { top: -6px; }
.nav-toggle span::after  { top: 6px; }

/* === 工具区 === */
.tool-section {
  padding: 32px 0 48px;
}

.tool-layout {
  display: grid;
  grid-template-columns: 1fr 380px;
  gap: 28px;
  align-items: start;
}

/* 上传/预览区 */
.tool-preview {
  background: var(--c-bg-card);
  border-radius: var(--r-lg);
  border: 1px solid var(--c-border);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  min-height: 480px;
  display: flex;
  flex-direction: column;
}

.upload-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 48px 32px;
  cursor: pointer;
  transition: all var(--duration-normal) var(--ease-out);
  border: 2px dashed transparent;
  margin: 16px;
  border-radius: var(--r-lg);
  background: var(--c-bg);
}

.upload-area:hover {
  border-color: var(--c-primary);
  background: var(--c-primary-light);
}

.upload-area.drag-over {
  border-color: var(--c-primary);
  background: var(--c-primary-light);
  transform: scale(1.01);
}

.upload-icon {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  background: var(--c-primary-pale);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}

.upload-icon svg {
  width: 32px;
  height: 32px;
  color: var(--c-primary);
}

.upload-title {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--c-text);
  margin-bottom: 8px;
}

.upload-hint {
  font-size: 0.85rem;
  color: var(--c-text-muted);
}

.upload-btn {
  margin-top: 20px;
  padding: 12px 28px;
  background: var(--c-primary);
  color: white;
  font-weight: 600;
  font-size: 0.95rem;
  border-radius: var(--r-full);
  transition: all var(--duration-fast);
  box-shadow: var(--shadow-primary);
}

.upload-btn:hover {
  background: var(--c-primary-hover);
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(37, 99, 235, 0.3);
}

/* Canvas预览 */
.preview-canvas-wrap {
  flex: 1;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 24px;
  position: relative;
  background: repeating-conic-gradient(#e5e7eb 0% 25%, transparent 0% 50%) 50% / 16px 16px;
}

.preview-canvas-wrap.active {
  display: flex;
}

.preview-canvas-wrap canvas {
  max-width: 100%;
  max-height: 420px;
  border-radius: var(--r-sm);
  box-shadow: var(--shadow-lg);
}

/* 重新上传 */
.re-upload-bar {
  display: none;
  padding: 12px 16px;
  border-top: 1px solid var(--c-border);
  justify-content: space-between;
  align-items: center;
}

.re-upload-bar.active {
  display: flex;
}

.re-upload-bar .file-name {
  font-size: 0.82rem;
  color: var(--c-text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 200px;
}

.re-upload-bar button {
  font-size: 0.82rem;
  color: var(--c-primary);
  background: var(--c-primary-light);
  padding: 6px 14px;
  border-radius: var(--r-full);
  font-weight: 500;
  transition: all var(--duration-fast);
}

.re-upload-bar button:hover {
  background: var(--c-primary-pale);
}

/* === 控制面板 === */
.tool-panel {
  background: var(--c-bg-card);
  border-radius: var(--r-lg);
  border: 1px solid var(--c-border);
  box-shadow: var(--shadow-sm);
  padding: 0;
  position: sticky;
  top: calc(var(--nav-height) + 20px);
}

.panel-header {
  padding: 20px 24px 16px;
  border-bottom: 1px solid var(--c-border-light);
}

.panel-header h2 {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--c-text);
}

.panel-body {
  padding: 20px 24px;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

/* 面板分组 */
.panel-group label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--c-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 10px;
}

/* 尺寸选择器 */
.size-select {
  width: 100%;
  padding: 10px 14px;
  border: 1px solid var(--c-border);
  border-radius: var(--r-md);
  font-size: 0.92rem;
  color: var(--c-text);
  background: var(--c-bg);
  transition: border-color var(--duration-fast);
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='%2394A3B8' viewBox='0 0 16 16'%3E%3Cpath d='M4 6l4 4 4-4'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
}

.size-select:focus {
  border-color: var(--c-primary);
  box-shadow: 0 0 0 3px var(--c-primary-glow);
}

.size-info {
  margin-top: 8px;
  padding: 10px 14px;
  background: var(--c-primary-light);
  border-radius: var(--r-md);
  font-size: 0.82rem;
  color: var(--c-primary-hover);
  line-height: 1.6;
  display: none;
}

.size-info.active {
  display: block;
}

/* 背景色选择 */
.bg-color-options {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.bg-color-btn {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 3px solid var(--c-border);
  cursor: pointer;
  transition: all var(--duration-fast);
  position: relative;
}

.bg-color-btn:hover {
  transform: scale(1.1);
}

.bg-color-btn.selected {
  border-color: var(--c-primary);
  box-shadow: 0 0 0 3px var(--c-primary-glow);
}

.bg-color-btn[data-color="white"] { background: #FFFFFF; }
.bg-color-btn[data-color="blue"]  { background: #438EDB; }
.bg-color-btn[data-color="red"]   { background: #D93A3A; }

.bg-color-btn.custom-color {
  background: conic-gradient(red, yellow, lime, aqua, blue, magenta, red);
  position: relative;
  overflow: hidden;
}

#customColorInput {
  position: absolute;
  width: 100%;
  height: 100%;
  opacity: 0;
  cursor: pointer;
}

/* 操作按钮组 */
.action-buttons {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding-top: 4px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 20px;
  border-radius: var(--r-md);
  font-size: 0.92rem;
  font-weight: 600;
  transition: all var(--duration-fast);
  white-space: nowrap;
}

.btn-primary {
  background: var(--c-primary);
  color: white;
  box-shadow: var(--shadow-primary);
}
.btn-primary:hover {
  background: var(--c-primary-hover);
  transform: translateY(-1px);
}
.btn-primary:disabled {
  opacity: 0.5;
  pointer-events: none;
  box-shadow: none;
}

.btn-accent {
  background: var(--c-accent);
  color: white;
  box-shadow: 0 4px 14px rgba(245, 158, 11, 0.25);
}
.btn-accent:hover {
  background: var(--c-accent-hover);
  transform: translateY(-1px);
}

.btn-outline {
  background: var(--c-bg-card);
  color: var(--c-text);
  border: 1px solid var(--c-border);
}
.btn-outline:hover {
  border-color: var(--c-primary);
  color: var(--c-primary);
  background: var(--c-primary-light);
}

.btn-download {
  background: linear-gradient(135deg, var(--c-success) 0%, #059669 100%);
  color: white;
  font-size: 1rem;
  padding: 14px 24px;
  box-shadow: 0 4px 14px rgba(16, 185, 129, 0.3);
}
.btn-download:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(16, 185, 129, 0.35);
}

/* AI抠图状态 */
.ai-status {
  display: none;
  align-items: center;
  gap: 10px;
  padding: 12px 16px;
  background: var(--c-primary-light);
  border-radius: var(--r-md);
  font-size: 0.85rem;
  color: var(--c-primary);
}

.ai-status.active {
  display: flex;
}

.ai-spinner {
  width: 18px;
  height: 18px;
  border: 2px solid var(--c-primary-pale);
  border-top-color: var(--c-primary);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* === 照片检测结果面板 === */
.check-result-panel {
  display: none;
  border-top: 1px solid var(--c-border-light);
  padding-top: 16px;
}

.check-result-panel.active {
  display: block;
}

.check-result-title {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--c-text);
  margin-bottom: 12px;
}

.check-item {
  padding: 8px 12px;
  border-radius: var(--r-md);
  font-size: 0.82rem;
  margin-bottom: 6px;
  line-height: 1.5;
}

.check-pass {
  background: #ECFDF5;
  color: #065F46;
}

.check-fail {
  background: #FEF2F2;
  color: #991B1B;
}

.check-warn {
  background: #FFFBEB;
  color: #92400E;
}

.check-hint {
  background: var(--c-bg);
  color: var(--c-text-muted);
  font-style: italic;
}

/* === 宫格排版预览 === */
.grid-preview-wrap {
  display: none;
  padding: 16px;
  border-top: 1px solid var(--c-border);
  background: var(--c-bg);
}

.grid-preview-wrap.active {
  display: block;
}

.grid-preview-title {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--c-text-secondary);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.grid-info {
  font-weight: 400;
  font-size: 0.78rem;
  color: var(--c-text-muted);
  background: var(--c-bg-card);
  padding: 2px 10px;
  border-radius: var(--r-full);
  border: 1px solid var(--c-border);
}

.grid-preview-wrap canvas {
  max-width: 100%;
  border-radius: var(--r-sm);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--c-border);
}

/* === 常用尺寸网格区 === */
.sizes-section {
  padding: 56px 0 64px;
}

.section-header {
  text-align: center;
  margin-bottom: 40px;
}

.section-header h2 {
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--c-text);
  margin-bottom: 10px;
}

.section-header p {
  font-size: 0.95rem;
  color: var(--c-text-secondary);
}

/* 分类标签页 */
.size-tabs {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-bottom: 32px;
  flex-wrap: wrap;
}

.size-tab {
  padding: 8px 20px;
  border-radius: var(--r-full);
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--c-text-secondary);
  background: var(--c-bg-card);
  border: 1px solid var(--c-border);
  cursor: pointer;
  transition: all var(--duration-fast);
}

.size-tab:hover {
  border-color: var(--c-primary);
  color: var(--c-primary);
}

.size-tab.active {
  background: var(--c-primary);
  color: white;
  border-color: var(--c-primary);
  box-shadow: var(--shadow-primary);
}

/* 尺寸卡片网格 - 桌面4列，移动2列 */
.size-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.size-card {
  background: var(--c-bg-card);
  border: 1px solid var(--c-border);
  border-radius: var(--r-lg);
  padding: 20px;
  cursor: pointer;
  transition: all var(--duration-normal) var(--ease-out);
  text-decoration: none;
  color: inherit;
  position: relative;
  overflow: hidden;
}

.size-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--c-primary);
  transform: scaleX(0);
  transition: transform var(--duration-normal) var(--ease-out);
}

.size-card:hover {
  border-color: var(--c-primary);
  box-shadow: var(--shadow-md);
  transform: translateY(-3px);
}

.size-card:hover::before {
  transform: scaleX(1);
}

.size-card-icon {
  font-size: 1.6rem;
  margin-bottom: 12px;
}

.size-card-name {
  font-size: 1rem;
  font-weight: 700;
  color: var(--c-text);
  margin-bottom: 6px;
}

.size-card-spec {
  font-size: 0.78rem;
  color: var(--c-text-muted);
  line-height: 1.5;
}

.size-card-spec span {
  display: inline-block;
  padding: 2px 8px;
  background: var(--c-bg);
  border-radius: var(--r-sm);
  margin-top: 4px;
  font-size: 0.75rem;
}

.size-card-tag {
  position: absolute;
  top: 12px;
  right: 12px;
  padding: 2px 8px;
  border-radius: var(--r-full);
  font-size: 0.68rem;
  font-weight: 600;
  background: var(--c-accent);
  color: white;
}

/* === 功能亮点区 === */
.features-section {
  padding: 56px 0 72px;
  background: linear-gradient(180deg, var(--c-bg) 0%, #E8F0FE 100%);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.feature-card {
  background: var(--c-bg-card);
  border-radius: var(--r-lg);
  padding: 28px 24px;
  text-align: center;
  border: 1px solid var(--c-border);
  transition: all var(--duration-normal) var(--ease-out);
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.feature-icon {
  width: 56px;
  height: 56px;
  margin: 0 auto 16px;
  border-radius: var(--r-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
}

.feature-icon.blue   { background: var(--c-primary-light); }
.feature-icon.green  { background: #ECFDF5; }
.feature-icon.amber  { background: #FFFBEB; }
.feature-icon.purple { background: #F5F3FF; }

.feature-card h3 {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--c-text);
  margin-bottom: 8px;
}

.feature-card p {
  font-size: 0.82rem;
  color: var(--c-text-secondary);
  line-height: 1.6;
}

/* === 页脚 === */
.footer {
  background: var(--c-text);
  color: var(--c-text-muted);
  padding: 40px 0 24px;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 32px;
  margin-bottom: 32px;
}

.footer-brand h3 {
  color: white;
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 10px;
}

.footer-brand p {
  font-size: 0.82rem;
  line-height: 1.7;
  color: #94A3B8;
}

.footer-col h4 {
  color: #CBD5E1;
  font-size: 0.82rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 14px;
}

.footer-col ul {
  list-style: none;
}

.footer-col li {
  margin-bottom: 8px;
}

.footer-col a {
  color: #94A3B8;
  font-size: 0.85rem;
  transition: color var(--duration-fast);
}

.footer-col a:hover {
  color: white;
}

.footer-bottom {
  padding-top: 20px;
  border-top: 1px solid #1E293B;
  font-size: 0.78rem;
  color: #64748B;
  text-align: center;
}

/* === Loading overlay === */
.loading-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.5);
  backdrop-filter: blur(4px);
  z-index: 200;
  align-items: center;
  justify-content: center;
}

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

.loading-box {
  background: white;
  padding: 32px 40px;
  border-radius: var(--r-lg);
  text-align: center;
  box-shadow: var(--shadow-xl);
}

.loading-box .ai-spinner {
  width: 36px;
  height: 36px;
  margin: 0 auto 16px;
  border-width: 3px;
}

.loading-box p {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--c-text);
}

/* === Toast 提示 === */
.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(80px);
  padding: 12px 24px;
  background: var(--c-text);
  color: white;
  border-radius: var(--r-full);
  font-size: 0.88rem;
  font-weight: 500;
  z-index: 300;
  opacity: 0;
  transition: all var(--duration-normal) var(--ease-out);
  pointer-events: none;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

.toast.error {
  background: var(--c-danger);
}

/* === 页面入场动画 === */
@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-up {
  animation: fadeUp 0.5s var(--ease-out) both;
}

.fade-up-delay-1 { animation-delay: 0.08s; }
.fade-up-delay-2 { animation-delay: 0.16s; }
.fade-up-delay-3 { animation-delay: 0.24s; }
.fade-up-delay-4 { animation-delay: 0.32s; }

/* === 响应式 === */
@media (max-width: 1024px) {
  .tool-layout {
    grid-template-columns: 1fr 340px;
  }
  .size-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 24px;
  }
}

@media (max-width: 768px) {
  :root {
    --nav-height: 56px;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: white;
    flex-direction: column;
    padding: 12px 16px;
    border-bottom: 1px solid var(--c-border);
    box-shadow: var(--shadow-md);
  }

  .nav-links.open {
    display: flex;
  }

  .nav-toggle {
    display: flex;
  }

  .tool-layout {
    grid-template-columns: 1fr;
  }

  .tool-panel {
    position: static;
  }

  .tool-preview {
    min-height: 360px;
  }

  .size-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
  }

  .size-card {
    padding: 16px;
  }

  .section-header h2 {
    font-size: 1.3rem;
  }

  .features-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }

  .feature-card {
    padding: 20px 16px;
  }
}