/* ==========================================================================
   Gemini 风格视觉：极光背景 + 玻璃拟态 + 渐变文字/按钮 + 入场动效
   全部用 CSS 实现，不引入任何依赖；动效统一尊重 prefers-reduced-motion。
   ========================================================================== */

/* ===== 设计变量 ===== */
:root {
  --brand-1: #4285f4;
  --brand-2: #9b72cb;
  --brand-3: #d96570;

  --bg: #08090d;
  --bg-elev: rgba(255, 255, 255, 0.045);
  --bg-elev-2: rgba(255, 255, 255, 0.075);
  --bg-inset: rgba(0, 0, 0, 0.28);
  --surface: rgba(255, 255, 255, 0.045);
  --surface-2: rgba(255, 255, 255, 0.08);
  --border: rgba(255, 255, 255, 0.10);
  --border-strong: rgba(255, 255, 255, 0.20);

  --text: #eef1f6;
  --text-dim: #a4abb8;
  --text-faint: #737b89;

  --accent: var(--brand-1);
  --accent-soft: color-mix(in srgb, var(--brand-1) 16%, transparent);
  --accent-line: color-mix(in srgb, var(--brand-1) 55%, transparent);

  --ok: #3fb950;
  --warn: #e3b341;
  --err: #ff7b72;

  --radius: 22px;
  --radius-sm: 14px;
  --shadow: 0 30px 60px -40px rgba(0, 0, 0, 0.95);
  --aurora-opacity: 0.55;

  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  --sans: system-ui, -apple-system, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

html[data-theme="light"] {
  --bg: #f7f9fd;
  --bg-elev: rgba(255, 255, 255, 0.75);
  --bg-elev-2: rgba(15, 23, 42, 0.045);
  --bg-inset: rgba(255, 255, 255, 0.85);
  --surface: rgba(255, 255, 255, 0.72);
  --surface-2: rgba(255, 255, 255, 0.92);
  --border: rgba(15, 23, 42, 0.10);
  --border-strong: rgba(15, 23, 42, 0.20);

  --text: #14171c;
  --text-dim: #55606f;
  --text-faint: #818b99;

  --accent: #1a73e8;
  --accent-soft: rgba(26, 115, 232, 0.10);
  --accent-line: rgba(26, 115, 232, 0.40);

  --ok: #1a7f37;
  --warn: #9a6700;
  --err: #d1242f;

  --shadow: 0 26px 50px -34px rgba(23, 43, 77, 0.45);
  --aurora-opacity: 0.34;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

::selection { background: color-mix(in srgb, var(--brand-2) 35%, transparent); }

/* ===== 会缓慢流动的极光背景 ===== */
body::before {
  content: "";
  position: fixed;
  inset: -25vmax;
  z-index: -2;
  pointer-events: none;
  opacity: var(--aurora-opacity);
  background:
    radial-gradient(40vmax 40vmax at 18% 10%, var(--brand-1), transparent 62%),
    radial-gradient(36vmax 36vmax at 84% 6%, var(--brand-2), transparent 62%),
    radial-gradient(44vmax 44vmax at 62% 92%, var(--brand-3), transparent 66%);
  filter: blur(72px) saturate(135%);
  animation: aurora 28s ease-in-out infinite alternate;
}

/* 顶部一层很淡的暗角，让文字始终清晰 */
body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background: radial-gradient(120% 90% at 50% 0%, transparent 30%, color-mix(in srgb, var(--bg) 78%, transparent) 100%);
}

@keyframes aurora {
  0%   { transform: translate3d(-2%, -1%, 0) scale(1)    rotate(0deg); }
  50%  { transform: translate3d(3%, 2%, 0)   scale(1.07) rotate(4deg); }
  100% { transform: translate3d(-1%, 3%, 0)  scale(1.03) rotate(-3deg); }
}

/* ===== 顶栏 ===== */
.topbar {
  position: sticky;
  top: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 10px 22px;
  border-bottom: 1px solid var(--border);
  background: color-mix(in srgb, var(--bg) 68%, transparent);
  backdrop-filter: blur(20px) saturate(180%);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  text-decoration: none;
  font-weight: 650;
  letter-spacing: 0.2px;
  flex: none;
}

.brand-mark {
  width: 32px; height: 32px;
  display: grid; place-items: center;
  border-radius: 11px;
  color: #fff;
  background: linear-gradient(140deg, var(--brand-1), var(--brand-2) 60%, var(--brand-3));
  background-size: 180% auto;
  box-shadow: 0 8px 20px -10px var(--brand-2);
  transition: transform .4s cubic-bezier(.2,.8,.3,1), background-position .6s ease;
}
.brand:hover .brand-mark { transform: rotate(-8deg) scale(1.06); background-position: 100% center; }

.brand-text { font-size: 15px; }

.topbar-actions { display: flex; align-items: center; gap: 6px; flex: none; margin-left: auto; }

.ghost-link {
  position: relative;
  color: var(--text-dim);
  text-decoration: none;
  font-size: 14px;
  padding: 6px 12px;
  border-radius: 999px;
  transition: color .2s, background .2s;
}
.ghost-link:hover { color: var(--text); background: var(--bg-elev-2); }

.icon-btn {
  display: grid; place-items: center;
  width: 36px; height: 36px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--bg-elev);
  color: var(--text-dim);
  cursor: pointer;
  transition: transform .35s cubic-bezier(.2,.8,.3,1), color .2s, border-color .2s, box-shadow .3s;
}
.icon-btn:hover {
  color: var(--text);
  border-color: var(--border-strong);
  transform: rotate(18deg) scale(1.06);
  box-shadow: 0 0 0 6px color-mix(in srgb, var(--brand-1) 12%, transparent);
}
html[data-theme="dark"] .i-sun { display: none; }
html[data-theme="light"] .i-moon { display: none; }

/* ===== 主体 ===== */
.app {
  flex: 1;
  width: 100%;
  max-width: 900px;
  margin: 0 auto;
  padding: 26px 20px 64px;
}

/* ===== 首屏 ===== */
.hero {
  position: relative;
  text-align: center;
  padding: 26px 0 26px;
  margin-bottom: 8px;
}

.hero::before {
  content: "";
  position: absolute;
  left: 50%; top: -90px;
  width: 480px; height: 320px;
  transform: translateX(-50%);
  background: radial-gradient(closest-side, color-mix(in srgb, var(--brand-2) 34%, transparent), transparent 70%);
  filter: blur(50px);
  pointer-events: none;
  z-index: -1;
  animation: breathe 9s ease-in-out infinite;
}

@keyframes breathe {
  0%, 100% { opacity: .55; transform: translateX(-50%) scale(1); }
  50%      { opacity: .95; transform: translateX(-50%) scale(1.12); }
}

.hero h1 {
  margin: 0 0 14px;
  font-size: clamp(27px, 5.2vw, 46px);
  line-height: 1.18;
  font-weight: 700;
  letter-spacing: -0.03em;
  background: linear-gradient(100deg,
    var(--text) 6%, var(--brand-1) 30%, var(--brand-2) 48%, var(--brand-3) 64%, var(--text) 94%);
  background-size: 260% auto;
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
  animation: sheen 10s linear infinite;
}

@keyframes sheen { to { background-position: 260% center; } }

.hero p {
  margin: 0 auto;
  max-width: 62ch;
  color: var(--text-dim);
  font-size: 15.5px;
}
.hero p strong { color: var(--text); font-weight: 600; }

.hero-note {
  margin-top: 14px !important;
  font-size: 13.5px !important;
  color: var(--text-faint) !important;
}

.hero-badges {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
  margin-top: 18px;
}
.badge {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-size: 12.5px;
  color: var(--text-dim);
  padding: 5px 13px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  backdrop-filter: blur(10px);
  transition: transform .25s cubic-bezier(.2,.8,.3,1), color .2s, border-color .2s;
}
.badge:hover { transform: translateY(-2px); color: var(--text); border-color: var(--border-strong); }
.badge .dot {
  width: 6px; height: 6px; border-radius: 50%;
  background: linear-gradient(140deg, var(--brand-1), var(--brand-2));
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--brand-1) 16%, transparent);
}

/* ===== 玻璃面板 ===== */
.panel {
  position: relative;
  padding: 18px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: linear-gradient(180deg, var(--surface), color-mix(in srgb, var(--surface) 35%, transparent));
  backdrop-filter: blur(16px);
  box-shadow: 0 1px 0 rgba(255, 255, 255, 0.06) inset, var(--shadow);
  transition: border-color .3s, box-shadow .35s, transform .35s cubic-bezier(.2,.8,.3,1);
}
.panel + .panel { margin-top: 14px; }
.panel:focus-within {
  border-color: color-mix(in srgb, var(--brand-1) 45%, var(--border));
  box-shadow: 0 1px 0 rgba(255, 255, 255, 0.06) inset,
              0 0 0 4px color-mix(in srgb, var(--brand-1) 12%, transparent),
              0 34px 70px -44px color-mix(in srgb, var(--brand-1) 70%, transparent);
}

/* ===== 提示词卡片 ===== */
.prompt-card { overflow: hidden; }
.prompt-card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 2px;
  background: linear-gradient(90deg, var(--brand-1), var(--brand-2), var(--brand-3), var(--brand-1));
  background-size: 220% auto;
  animation: sheen 6s linear infinite;
}

.prompt-title {
  margin: 2px 0 8px;
  font-size: 17px;
  font-weight: 650;
  letter-spacing: -0.01em;
}

.prompt-lead { margin: 0 0 12px; font-size: 13.5px; color: var(--text-dim); max-width: 68ch; }
.prompt-lead strong { color: var(--text); }

.prompt-box {
  position: relative;
  margin: 0 0 12px;
  padding: 13px 15px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-inset);
  color: var(--text);
  font-family: var(--mono);
  font-size: 12.5px;
  line-height: 1.75;
  white-space: pre-wrap;
  word-break: break-word;
}
.prompt-box::before {
  content: "";
  position: absolute;
  left: 0; top: 12px; bottom: 12px;
  width: 3px;
  border-radius: 0 3px 3px 0;
  background: linear-gradient(180deg, var(--brand-1), var(--brand-2), var(--brand-3));
}
.prompt-box::after {
  content: "▍";
  margin-left: 2px;
  color: var(--brand-2);
  animation: blink 1.15s steps(2, start) infinite;
}

@keyframes blink { 50% { opacity: 0; } }

/* ===== 表单控件 ===== */
.field { display: block; }

.lbl {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px;
  margin-bottom: 8px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-dim);
  letter-spacing: 0.01em;
}
.hint { font-weight: 400; font-size: 12px; color: var(--text-faint); }

textarea, input[type="text"], input[type="number"] {
  width: 100%;
}

textarea, input[type="text"], input[type="number"], select, input[type="file"] {
  padding: 11px 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: color-mix(in srgb, var(--bg-inset) 80%, transparent);
  color: var(--text);
  font: inherit;
  outline: none;
  transition: border-color .2s, box-shadow .3s, background .2s;
}

/* select / file 放在 .opts 这种横向排布里时不能被拉满整行 */
select { width: auto; min-width: 92px; max-width: 100%; padding: 10px 12px; }
input[type="file"] { max-width: 100%; padding: 8px 10px; font-size: 13px; color: var(--text-dim); }
input[type="file"]::file-selector-button {
  margin-right: 10px;
  padding: 5px 12px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--bg-elev-2);
  color: var(--text);
  font: inherit;
  font-size: 12.5px;
  cursor: pointer;
  transition: border-color .2s, background .2s;
}
input[type="file"]::file-selector-button:hover { border-color: var(--border-strong); }
textarea {
  font-family: var(--mono);
  font-size: 12.8px;
  line-height: 1.75;
  resize: vertical;
  tab-size: 2;
}
textarea::placeholder, input::placeholder { color: var(--text-faint); }

textarea:focus, input:focus, select:focus {
  border-color: color-mix(in srgb, var(--brand-1) 55%, transparent);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--brand-1) 15%, transparent);
  background: color-mix(in srgb, var(--bg-inset) 60%, transparent);
}

select { cursor: pointer; }

input[type="checkbox"] { accent-color: var(--brand-1); width: auto; }

label.opt {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text-dim);
}

/* ===== 按钮 ===== */
.btn {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 17px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--bg-elev-2);
  color: var(--text);
  font: inherit;
  font-size: 14px;
  font-weight: 560;
  cursor: pointer;
  overflow: hidden;
  isolation: isolate;
  -webkit-tap-highlight-color: transparent;
  transition: transform .2s cubic-bezier(.2,.8,.3,1), box-shadow .3s, border-color .2s, background .2s, color .2s;
}
.btn::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background: linear-gradient(105deg, transparent 34%, rgba(255, 255, 255, 0.20) 50%, transparent 66%);
  transform: translateX(-130%);
  transition: transform .65s ease;
}
.btn:hover { transform: translateY(-2px); border-color: var(--border-strong); }
.btn:hover::after { transform: translateX(130%); }
.btn:active { transform: translateY(0) scale(.98); }
.btn:focus-visible { outline: 2px solid var(--accent-line); outline-offset: 2px; }

.btn.primary {
  border-color: transparent;
  color: #fff;
  background-image: linear-gradient(100deg, var(--brand-1), var(--brand-2) 55%, var(--brand-3));
  background-size: 170% auto;
  box-shadow: 0 12px 28px -16px color-mix(in srgb, var(--brand-1) 90%, transparent);
}
.btn.primary:hover {
  background-position: 100% center;
  box-shadow: 0 18px 36px -16px color-mix(in srgb, var(--brand-2) 90%, transparent);
}

.btn.tiny { font-size: 12.5px; padding: 6px 13px; font-weight: 500; }
.btn.copied { border-color: transparent; color: #fff; background-image: linear-gradient(100deg, var(--ok), #2ea043); }

/* ===== 布局小工具 ===== */
.row { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; }
.row.wrap-end { justify-content: flex-end; }
.opts { display: flex; flex-wrap: wrap; gap: 10px 16px; align-items: center; }
.opts > * { flex: none; }
.io { display: grid; gap: 14px; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.kv { display: grid; gap: 4px; font-size: 13px; }
.kv .k { color: var(--text-faint); font-size: 12px; }
.kv .v { font-family: var(--mono); word-break: break-all; }
.mono { font-family: var(--mono); }

/* ===== 提示信息 ===== */
.msg {
  display: block;
  margin-top: 10px;
  padding: 9px 13px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--bg-elev-2);
  font-size: 13px;
  color: var(--text-dim);
}
.msg.err  { color: var(--err);  border-color: color-mix(in srgb, var(--err) 35%, transparent);  background: color-mix(in srgb, var(--err) 10%, transparent); }
.msg.warn { color: var(--warn); border-color: color-mix(in srgb, var(--warn) 35%, transparent); background: color-mix(in srgb, var(--warn) 10%, transparent); }
.msg.ok   { color: var(--ok);   border-color: color-mix(in srgb, var(--ok) 35%, transparent);   background: color-mix(in srgb, var(--ok) 10%, transparent); }

/* ===== 结果统计 ===== */
.stat-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(118px, 1fr));
  gap: 10px;
  margin-top: 12px;
}
.stat {
  padding: 11px 13px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-elev-2);
  animation: pop .4s cubic-bezier(.2,.9,.3,1.2) both;
}
.stat:nth-child(2) { animation-delay: .05s; }
.stat:nth-child(3) { animation-delay: .1s; }
.stat:nth-child(4) { animation-delay: .15s; }
.stat:nth-child(5) { animation-delay: .2s; }
.stat .k { font-size: 11.5px; color: var(--text-faint); }
.stat .v { font-size: 16px; font-weight: 620; letter-spacing: -0.01em; }

@keyframes pop { from { opacity: 0; transform: translateY(8px) scale(.96); } to { opacity: 1; transform: none; } }

/* ===== 输出框 ===== */
.out {
  padding: 13px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-inset);
  font-family: var(--mono);
  font-size: 12.8px;
  white-space: pre-wrap;
  word-break: break-word;
  overflow: auto;
}
.out.tall { min-height: 180px; }

/* ===== 正文（静态 SEO 段落） ===== */
.prose {
  max-width: 720px;
  margin: 46px auto 0;
}
.prose h2 {
  position: relative;
  margin: 0 0 16px;
  padding-bottom: 10px;
  font-size: 21px;
  font-weight: 660;
  letter-spacing: -0.02em;
}
.prose h2::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 54px; height: 2px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--brand-1), var(--brand-2), var(--brand-3));
}
.prose h3 { margin: 24px 0 6px; font-size: 15.5px; font-weight: 620; }
.prose p { margin: 0 0 12px; color: var(--text-dim); }
.prose p strong { color: var(--text); }
.prose ol, .prose ul { margin: 0 0 12px; padding-left: 22px; color: var(--text-dim); }
.prose li { margin-bottom: 7px; }
.prose li strong { color: var(--text); }
.prose code {
  font-family: var(--mono);
  font-size: 12.4px;
  padding: 2px 6px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg-elev-2);
  color: var(--text);
  white-space: nowrap;
}

.callout {
  padding: 14px 16px;
  border: 1px solid color-mix(in srgb, var(--brand-1) 30%, transparent);
  border-left-width: 3px;
  border-radius: 4px var(--radius-sm) var(--radius-sm) 4px;
  background: color-mix(in srgb, var(--brand-1) 9%, transparent);
  color: var(--text-dim);
}
.callout strong { color: var(--text); }
.callout code { background: color-mix(in srgb, var(--bg) 40%, transparent); }

/* ===== 页脚 ===== */
.footer {
  position: relative;
  padding: 22px 20px 30px;
  text-align: center;
  font-size: 12.5px;
  color: var(--text-faint);
}
.footer::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--border-strong), transparent);
}

/* ===== 复制成功提示 ===== */
.toast {
  position: fixed;
  left: 50%;
  bottom: 30px;
  z-index: 60;
  padding: 10px 20px;
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  backdrop-filter: blur(16px) saturate(170%);
  box-shadow: var(--shadow);
  color: var(--text);
  font-size: 13.5px;
  opacity: 0;
  transform: translate(-50%, 14px) scale(.96);
  pointer-events: none;
  transition: opacity .28s ease, transform .38s cubic-bezier(.2,.9,.3,1.2);
}
.toast.show { opacity: 1; transform: translate(-50%, 0) scale(1); }
.toast:empty { display: none; }

/* ===== 入场动效 ===== */
@keyframes rise {
  from { opacity: 0; transform: translateY(20px) scale(.994); }
  to   { opacity: 1; transform: none; }
}

@media (prefers-reduced-motion: no-preference) {
  .hero        { animation: rise .75s cubic-bezier(.22,.85,.28,1) both; }
  .prompt-card { animation: rise .75s .1s cubic-bezier(.22,.85,.28,1) both; }
  .tool-body   { animation: rise .75s .2s cubic-bezier(.22,.85,.28,1) both; }
  .prose       { animation: rise .8s .1s cubic-bezier(.22,.85,.28,1) both; }
}

/* ===== 滚动条 ===== */
* { scrollbar-width: thin; scrollbar-color: var(--border-strong) transparent; }
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-thumb {
  background: var(--border-strong);
  border: 3px solid transparent;
  background-clip: content-box;
  border-radius: 999px;
}
::-webkit-scrollbar-thumb:hover { background: color-mix(in srgb, var(--brand-1) 60%, transparent); background-clip: content-box; }

/* ===== 响应式 ===== */
@media (max-width: 640px) {
  .app { padding: 18px 15px 48px; }
  .hero { padding-top: 14px; }
  .hero h1 { font-size: 27px; }
  .hero p { font-size: 14.5px; }
  .prose { margin-top: 34px; }
  .panel { padding: 15px; border-radius: 18px; }
  .btn { padding: 9px 15px; }
  .row .btn { flex: 1 1 auto; justify-content: center; }
}

/* ===== 无障碍：关闭动效 ===== */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }
}

/* ===== 提示词卡片的标题行 ===== */
.prompt-head { display: flex; align-items: center; gap: 10px; margin: 2px 0 8px; }
.prompt-head .prompt-title { margin: 0; }
.prompt-head .step + .prompt-title { font-size: 16px; font-weight: 620; }
.step {
  flex: none;
  font-size: 11.5px;
  font-weight: 620;
  letter-spacing: 0.02em;
  padding: 3px 10px;
  border-radius: 999px;
  color: #fff;
  background: linear-gradient(100deg, var(--brand-1), var(--brand-2));
  box-shadow: 0 6px 16px -10px var(--brand-2);
}