/* ============ 主题变量 ============ */
:root {
  --bg: #f4f1f8;
  --surface: #ffffff;
  --surface-2: #f7f2fa;
  --on-surface: #1c1b1f;
  --on-surface-variant: #49454f;
  --primary: #6750a4;
  --on-primary: #ffffff;
  --primary-container: #eaddff;
  --on-primary-container: #21005d;
  --outline: #79747e;
  --outline-variant: #cac4d0;
  --error: #b3261e;
  --shadow: 0 4px 16px rgba(0, 0, 0, 0.10);
  --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.14);
  --radius: 18px;
}

html.dark {
  --bg: #141218;
  --surface: #1d1b20;
  --surface-2: #241f2c;
  --on-surface: #e6e0e9;
  --on-surface-variant: #cac4d0;
  --primary: #d0bcff;
  --on-primary: #381e72;
  --primary-container: #4f378b;
  --on-primary-container: #eaddff;
  --outline: #938f99;
  --outline-variant: #49454f;
  --error: #f2b8b5;
  --shadow: 0 4px 16px rgba(0, 0, 0, 0.45);
  --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.55);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--on-surface);
  font-family: "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 15px;
  line-height: 1.5;
  transition: background 0.25s, color 0.25s;
}

.svg-defs { position: absolute; width: 0; height: 0; overflow: hidden; }
.icon { width: 22px; height: 22px; fill: currentColor; display: inline-block; vertical-align: middle; }

/* ============ 顶栏 ============ */
.app-bar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 16px;
  background: color-mix(in srgb, var(--surface) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--outline-variant);
}
.app-title { font-size: 17px; font-weight: 600; letter-spacing: 0.2px; }
.spacer { flex: 1; }

.icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border: none;
  border-radius: 50%;
  background: transparent;
  color: var(--on-surface-variant);
  cursor: pointer;
  transition: background 0.18s, color 0.18s;
}
.icon-btn:hover { background: color-mix(in srgb, var(--primary) 12%, transparent); color: var(--primary); }
.icon-btn:active { background: color-mix(in srgb, var(--primary) 22%, transparent); }

/* ============ 布局 ============ */
.container {
  max-width: 920px;
  margin: 0 auto;
  padding: 24px 16px 48px;
}

.card {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}
.card-header { padding: 24px 24px 16px; }
.brand { display: flex; align-items: center; gap: 16px; }
.brand-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 52px;
  height: 52px;
  border-radius: 16px;
  background: var(--primary-container);
  color: var(--primary);
  flex: 0 0 auto;
}
.brand-icon .icon { width: 30px; height: 30px; }
.brand-text h1 { margin: 0; font-size: 22px; font-weight: 700; }
.subtitle { margin: 4px 0 0; font-size: 13px; color: var(--on-surface-variant); }

.divider { border: none; border-top: 1px solid var(--outline-variant); margin: 0; }
.card-body { padding: 20px 24px 28px; }

/* ============ 表单控件 ============ */
.field-label {
  display: block;
  font-size: 13px;
  font-weight: 500;
  color: var(--on-surface-variant);
  margin-bottom: 6px;
}
.select, .input, .textarea {
  width: 100%;
  font: inherit;
  color: var(--on-surface);
  background: var(--surface-2);
  border: 1px solid var(--outline-variant);
  border-radius: 12px;
  padding: 12px 14px;
  transition: border-color 0.18s, box-shadow 0.18s;
  outline: none;
}
.select:focus, .input:focus, .textarea:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--primary) 20%, transparent);
}
.textarea {
  resize: vertical;
  min-height: 160px;
  font-family: ui-monospace, "SFMono-Regular", "Menlo", "Consolas", monospace;
  font-size: 13.5px;
  line-height: 1.6;
  white-space: pre;
  overflow: auto;
}
.select { cursor: pointer; appearance: none;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 24 24'><path fill='%2379747e' d='M7 10l5 5 5-5z'/></svg>");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 40px;
}

/* ============ 面板 ============ */
.panel { display: flex; flex-direction: column; gap: 16px; margin-top: 18px; }
.options-row { display: flex; flex-wrap: wrap; gap: 12px; }
.options-row > * { flex: 1 1 200px; }

.actions { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }
.actions .spacer { flex: 1; }
.hint { font-size: 12px; color: var(--on-surface-variant); margin: 0; }

/* ============ 按钮 ============ */
.btn {
  font: inherit;
  font-weight: 600;
  border: none;
  border-radius: 999px;
  padding: 10px 20px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition: filter 0.18s, background 0.18s, transform 0.05s;
}
.btn:active { transform: translateY(1px); }
.btn .icon { width: 19px; height: 19px; }
.btn.primary { background: var(--primary); color: var(--on-primary); }
.btn.primary:hover { filter: brightness(1.06); }
.btn.tonal { background: var(--primary-container); color: var(--on-primary-container); }
.btn.tonal:hover { filter: brightness(0.97); }
.btn.outlined { background: transparent; color: var(--primary); border: 1px solid var(--outline); }
.btn.outlined:hover { background: color-mix(in srgb, var(--primary) 8%, transparent); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

/* ============ 文件拖拽 ============ */
.file-drop {
  border: 2px dashed var(--outline-variant);
  border-radius: 16px;
  padding: 30px 16px;
  text-align: center;
  cursor: pointer;
  background: var(--surface-2);
  color: var(--on-surface-variant);
  transition: border-color 0.2s, background 0.2s;
}
.file-drop:hover, .file-drop.dragover {
  border-color: var(--primary);
  background: color-mix(in srgb, var(--primary) 8%, var(--surface-2));
}
.file-drop .icon { width: 40px; height: 40px; color: var(--primary); }
.file-drop p { margin: 8px 0 0; font-size: 14px; }
.file-drop .file-name { margin-top: 8px; font-size: 13px; font-weight: 600; color: var(--primary); word-break: break-all; }

/* range */
.range-row { display: flex; align-items: center; gap: 12px; }
.range-row input[type="range"] { flex: 1; accent-color: var(--primary); }

/* ============ 图片预览 ============ */
.preview-wrap { margin-top: 8px; text-align: center; }
.preview-wrap img {
  max-width: 100%;
  max-height: 320px;
  border-radius: 12px;
  border: 1px solid var(--outline-variant);
  background:
    repeating-conic-gradient(#bbb 0% 25%, #fff 0% 50%) 50% / 20px 20px;
}
.preview-meta { font-size: 12px; color: var(--on-surface-variant); margin-top: 6px; }

/* ============ 页脚 ============ */
.site-footer { text-align: center; margin-top: 28px; font-size: 13px; color: var(--on-surface-variant); }
.site-footer .muted { opacity: 0.7; font-size: 12px; margin-top: 4px; }

/* ============ 弹窗 ============ */
.dialog {
  border: none;
  border-radius: var(--radius);
  padding: 0;
  max-width: 460px;
  width: calc(100% - 32px);
  background: var(--surface);
  color: var(--on-surface);
  box-shadow: var(--shadow-lg);
}
.dialog::backdrop { background: rgba(0, 0, 0, 0.45); }
.dialog-head { font-size: 18px; font-weight: 700; padding: 22px 24px 8px; }
.dialog-content { padding: 4px 24px 16px; font-size: 14px; line-height: 1.7; }
.dialog-content ul { padding-left: 20px; margin: 8px 0; }
.dialog-content code { background: var(--surface-2); padding: 2px 6px; border-radius: 6px; font-size: 12px; }
.dialog-actions { display: flex; justify-content: flex-end; padding: 8px 16px 18px; gap: 10px; }

/* ============ Toast ============ */
.toast {
  position: fixed;
  left: 50%;
  bottom: 32px;
  transform: translateX(-50%) translateY(20px);
  background: var(--on-surface);
  color: var(--surface);
  padding: 12px 20px;
  border-radius: 10px;
  font-size: 14px;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s, transform 0.25s;
  z-index: 9999;
  max-width: 90vw;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }
.toast.error { background: var(--error); color: #fff; }

/* ============ 响应式 ============ */
@media (max-width: 600px) {
  .card-header, .card-body { padding-left: 16px; padding-right: 16px; }
  .brand-text h1 { font-size: 19px; }
  .actions .spacer { display: none; }
}