/* ==========================================================================
   common.css — ox-skull-fe 通用样式
   所有页面共享的基础变量、重置、按钮、容器等通用规则
   ========================================================================== */

:root {
  --nnk-primary: #4f46e5;          /* 主色 indigo */
  --nnk-primary-2: #7c3aed;        /* 渐变次色 violet */
  --nnk-accent: #06b6d4;           /* 强调色 cyan */
  --nnk-bg: #ffffff;
  --nnk-bg-soft: #f8f9fe;
  --nnk-text: #0f172a;
  --nnk-text-muted: #5b6472;
  --nnk-border: #e8eaf2;
  --nnk-border-strong: #d8dcf0;
  --nnk-radius: 14px;
  --nnk-radius-lg: 24px;
  --nnk-shadow: 0 12px 40px rgba(79, 70, 229, 0.10);
  --nnk-shadow-lg: 0 24px 70px rgba(79, 70, 229, 0.18);
  --nnk-font: "PingFang SC", "Microsoft YaHei", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --nnk-grad: linear-gradient(135deg, #4f46e5 0%, #7c3aed 55%, #06b6d4 130%);
  --nnk-grad-soft: linear-gradient(135deg, rgba(79, 70, 229, 0.10), rgba(124, 58, 237, 0.07), rgba(6, 182, 212, 0.10));
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--nnk-font);
  color: var(--nnk-text);
  background: var(--nnk-bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: inherit; text-decoration: none; }
ul { list-style: none; }
img { max-width: 100%; display: block; }

/* 容器 */
.nnk-container {
  width: 100%;
  max-width: 1160px;
  margin: 0 auto;
  padding: 0 24px;
}

/* 渐变文字 */
.nnk-grad-text {
  background: var(--nnk-grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* 按钮 */
.nnk-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 30px;
  border-radius: 999px;
  border: none;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.18s ease, box-shadow 0.25s ease, border-color 0.2s ease, color 0.2s ease;
  white-space: nowrap;
}
.nnk-btn:hover { transform: translateY(-2px); }
.nnk-btn:active { transform: translateY(0); }
.nnk-btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
  box-shadow: none;
  transform: none;
}

.nnk-btn--primary {
  background: var(--nnk-grad);
  color: #fff;
  box-shadow: 0 8px 24px rgba(79, 70, 229, 0.32), inset 0 1px 0 rgba(255, 255, 255, 0.25);
}
.nnk-btn--primary:hover {
  box-shadow: 0 14px 34px rgba(79, 70, 229, 0.42), inset 0 1px 0 rgba(255, 255, 255, 0.25);
}

.nnk-btn--ghost {
  background: #fff;
  color: var(--nnk-text);
  border: 1px solid var(--nnk-border-strong);
}
.nnk-btn--ghost:hover {
  border-color: var(--nnk-primary);
  color: var(--nnk-primary);
  box-shadow: 0 6px 18px rgba(79, 70, 229, 0.10);
}

/* 区块标题 */
.nnk-section { padding: 96px 0; }
.nnk-section__tag {
  display: inline-block;
  padding: 7px 18px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--nnk-primary);
  background: rgba(79, 70, 229, 0.07);
  border: 1px solid rgba(79, 70, 229, 0.12);
  margin-bottom: 18px;
}
.nnk-section__title {
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.01em;
  margin-bottom: 16px;
}
.nnk-section__desc {
  font-size: 17px;
  line-height: 1.75;
  color: var(--nnk-text-muted);
  max-width: 640px;
}
.nnk-section--center { text-align: center; }
.nnk-section--center .nnk-section__desc { margin: 0 auto; }

/* ==========================================================================
   功能页通用样式(抠图 / 去背景 / AI 生图)
   ========================================================================== */

/* 功能页统一背景(让白色卡片浮起来) */
.nnk-page {
  background: #f7f8fc;
  background-image: linear-gradient(180deg, #edf0fb 0%, #f7f8fc 380px);
}

/* 顶部工具栏 */
.appbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--nnk-border);
}
.appbar__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  gap: 16px;
}
.appbar__logo {
  display: flex;
  align-items: center;
  gap: 9px;
  font-size: 18px;
  font-weight: 800;
  letter-spacing: -0.01em;
  flex: none;
  background: var(--nnk-grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.appbar__logo svg { width: 28px; height: 28px; }
.appbar__tabs { display: flex; gap: 6px; overflow-x: auto; }
.appbar__tab {
  padding: 8px 16px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 600;
  color: var(--nnk-text-muted);
  white-space: nowrap;
  transition: color 0.2s, background 0.2s, box-shadow 0.2s;
}
.appbar__tab:hover { color: var(--nnk-primary); }
.appbar__tab.is-active {
  color: #fff;
  background: var(--nnk-grad);
  box-shadow: 0 6px 18px rgba(79, 70, 229, 0.28);
}

/* 页面标题区 */
.page-head { padding: 44px 0 8px; text-align: center; }
.page-head h1 { font-size: clamp(26px, 4vw, 38px); font-weight: 800; letter-spacing: -0.01em; margin-bottom: 10px; }
.page-head p { color: var(--nnk-text-muted); font-size: 16px; }

/* 棋盘格(透明底预览) */
.checkerboard {
  background-color: #fff;
  background-image:
    linear-gradient(45deg, #f0f2f7 25%, transparent 25%),
    linear-gradient(-45deg, #f0f2f7 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #f0f2f7 75%),
    linear-gradient(-45deg, transparent 75%, #f0f2f7 75%);
  background-size: 16px 16px;
  background-position: 0 0, 0 8px, 8px -8px, -8px 0;
}

/* 工具两栏布局 */
.tool {
  display: grid;
  grid-template-columns: 380px 1fr;
  gap: 28px;
  align-items: start;
  padding: 32px 0 80px;
}
@media (max-width: 920px) { .tool { grid-template-columns: 1fr; } }

/* 上传拖拽区 */
.dropzone {
  border: 2px dashed var(--nnk-border-strong);
  border-radius: var(--nnk-radius-lg);
  padding: 48px 24px;
  text-align: center;
  cursor: pointer;
  color: var(--nnk-text-muted);
  transition: border-color 0.2s, background 0.2s;
}
.dropzone:hover, .dropzone.is-drag {
  border-color: var(--nnk-primary);
  background: rgba(79, 70, 229, 0.04);
}
.dropzone svg { width: 44px; height: 44px; color: var(--nnk-primary); margin-bottom: 14px; }
.dropzone p { font-size: 15px; }
.dropzone .hint { font-size: 13px; color: #9ca3af; margin-top: 6px; }

/* 加载动画 */
.spinner {
  width: 36px; height: 36px;
  border: 3px solid rgba(79, 70, 229, 0.16);
  border-top-color: var(--nnk-primary);
  border-radius: 50%;
  margin: 0 auto 14px;
  animation: nnkSpin 0.8s linear infinite;
}
@keyframes nnkSpin { to { transform: rotate(360deg); } }