/* =========================================================
   数题胶片 · AI 数学应用题生成器
   主题：复古胶片 —— 暖色调 / 胶片颗粒 / 柔和暗角 / 复古排版
   ========================================================= */
:root {
  --c-primary: #4db030;
  --c-accent: #4abf7e;
  --c-cta: #d52ac2;
  --c-bg: #f9fbf8;
  --c-surface: #ffffff;
  --c-text: #1f2c1b;
  --c-muted: #637a5c;
  --c-border: #dde6db;
  --radius: 8px;
  --font-title: 'Noto Serif SC', 'Songti SC', Georgia, 'Times New Roman', serif;
  --font-body: system-ui, -apple-system, 'PingFang SC', 'Microsoft YaHei', 'Segoe UI', sans-serif;
  --shadow-warm: 0 12px 26px -14px rgba(31, 44, 27, .28);
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--c-text);
  background:
    radial-gradient(120% 90% at 12% -8%, rgba(240, 214, 170, .55), transparent 55%),
    radial-gradient(120% 90% at 88% 108%, rgba(216, 162, 96, .22), transparent 55%),
    var(--c-bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img, svg { max-width: 100%; }
a { color: var(--c-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

.wrap { max-width: 1080px; margin: 0 auto; padding: 0 20px; }

/* ---------------- 胶片层叠（颗粒 / 暗角 / 暖色叠层） ---------------- */
.grain, .vignette, .warm {
  position: fixed; inset: -20px; z-index: 70; pointer-events: none;
}
.grain {
  mix-blend-mode: soft-light; opacity: .18;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='160' height='160'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.82' numOctaves='3' stitchTiles='stitch'/></filter><rect width='160' height='160' filter='url(%23n)'/></svg>");
  animation: grainFlicker 7s ease-in-out infinite;
}
@keyframes grainFlicker {
  0%, 100% { opacity: .16; }
  50% { opacity: .24; }
}
.vignette {
  z-index: 69; mix-blend-mode: normal; opacity: 1;
  background: radial-gradient(ellipse 120% 100% at 50% 42%, transparent 56%, rgba(31, 44, 27, .13) 82%, rgba(31, 44, 27, .22) 100%);
}
.warm {
  z-index: 68; mix-blend-mode: soft-light; opacity: 1;
  background:
    radial-gradient(120% 90% at 15% 0%, rgba(216, 162, 96, .4), transparent 55%),
    radial-gradient(120% 90% at 85% 100%, rgba(213, 42, 194, .12), transparent 55%),
    linear-gradient(180deg, rgba(240, 214, 170, .2), transparent 45%);
}

/* ---------------- 顶部与导航 ---------------- */
.site-header {
  position: sticky; top: 0; z-index: 60;
  background: rgba(249, 251, 248, .9);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--c-border);
}
.sprocket {
  height: 11px;
  background: var(--c-primary);
  background-image: repeating-linear-gradient(90deg,
    transparent 0 16px, rgba(249, 251, 248, .9) 16px 30px);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding-top: 12px; padding-bottom: 12px; flex-wrap: wrap; }
.brand { display: inline-flex; align-items: center; gap: 10px; }
.brand:hover { text-decoration: none; }
.brand-mark {
  width: 40px; height: 40px; border-radius: var(--radius);
  display: grid; place-items: center; font-size: 20px;
  background: linear-gradient(160deg, var(--c-primary), var(--c-accent));
  box-shadow: 0 6px 14px -6px rgba(77, 176, 48, .7);
}
.brand-text { display: flex; flex-direction: column; line-height: 1.2; }
.brand-text strong { font-family: var(--font-title); font-size: 19px; letter-spacing: 2px; color: var(--c-text); }
.brand-text small { font-size: 12px; color: var(--c-muted); letter-spacing: 1px; }
.nav { display: flex; gap: 6px; flex-wrap: wrap; }
.nav a {
  font-size: 14px; font-weight: 600; color: var(--c-muted);
  padding: 8px 14px; border-radius: var(--radius);
  border: 1px solid transparent; transition: all .18s ease;
}
.nav a:hover { color: var(--c-text); background: rgba(77, 176, 48, .08); text-decoration: none; }
.nav a.active { color: #fff; background: var(--c-primary); box-shadow: 0 6px 14px -6px rgba(77, 176, 48, .8); }

/* ---------------- 首页 Hero ---------------- */
.hero { display: grid; grid-template-columns: 1.15fr .85fr; gap: 36px; align-items: center; padding: 46px 0 12px; }
.hero-copy { position: relative; z-index: 1; }
.stamp {
  display: inline-block; padding: 4px 14px; margin-bottom: 16px;
  border: 1.6px dashed var(--c-cta); color: var(--c-cta);
  border-radius: var(--radius); transform: rotate(-2deg);
  font-size: 13px; letter-spacing: 3px; font-weight: 600;
  background: rgba(213, 42, 194, .05);
}
.hero h1 {
  margin: 0 0 16px; font-family: var(--font-title); font-weight: 900;
  font-size: clamp(32px, 5.2vw, 54px); line-height: 1.18; letter-spacing: 1px;
}
.hero h1 .hl { color: var(--c-primary); position: relative; }
.hero h1 .hl::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: 4px; height: 10px;
  background: rgba(213, 42, 194, .22); border-radius: 4px; z-index: -1;
}
.lead { color: var(--c-muted); font-size: 17px; max-width: 520px; margin: 0 0 22px; }
.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; }

.hero-photo { position: relative; height: 300px; z-index: 1; }
.pola {
  position: absolute; width: 190px; background: var(--c-surface);
  border: 1px solid var(--c-border); border-radius: var(--radius);
  box-shadow: var(--shadow-warm); padding: 14px 14px 10px;
  transition: transform .3s ease, box-shadow .3s ease;
  animation: fadeUp .7s both;
}
.pola span { display: block; font-family: var(--font-title); font-size: 34px; font-weight: 900; letter-spacing: 2px; text-align: center; padding: 26px 0; color: var(--c-text); }
.pola i { display: block; font-style: normal; font-size: 12px; color: var(--c-muted); text-align: center; border-top: 1px dashed var(--c-border); padding-top: 8px; letter-spacing: 1px; }
.pola::before { content: ""; position: absolute; inset: 6px; border: 1px dashed rgba(77, 176, 48, .35); border-radius: 6px; pointer-events: none; }
.pola.p1 { top: 4px; left: 4px; transform: rotate(-6deg); z-index: 3; animation-delay: .05s; }
.pola.p2 { top: 44px; right: 0; transform: rotate(5deg); z-index: 2; animation-delay: .15s; }
.pola.p3 { bottom: 0; left: 42px; transform: rotate(-2deg); z-index: 4; animation-delay: .25s; }
.pola:hover { transform: rotate(0deg) translateY(-4px); box-shadow: 0 22px 36px -16px rgba(31, 44, 27, .35); }

/* ---------------- 卡片 / 面板 ---------------- */
.card {
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-warm);
}
.panel { padding: 24px 26px; margin: 30px 0; position: relative; overflow: hidden; }
.panel::before {
  content: ""; position: absolute; left: 0; top: 0; right: 0; height: 4px;
  background: linear-gradient(90deg, var(--c-primary), var(--c-accent), var(--c-cta));
}
.panel-head { display: flex; align-items: baseline; justify-content: space-between; gap: 14px; flex-wrap: wrap; margin-bottom: 18px; }
.panel-head h2, .results-title h2 { font-family: var(--font-title); font-size: 22px; margin: 0; letter-spacing: 1px; }
.panel-head p { margin: 0; color: var(--c-muted); font-size: 14px; }

/* ---------------- 表单 ---------------- */
.grid-form { display: grid; grid-template-columns: repeat(5, 1fr); gap: 16px; align-items: end; }
.field { display: flex; flex-direction: column; gap: 7px; }
.field label { font-size: 13px; font-weight: 600; letter-spacing: 1px; color: var(--c-muted); }
select, input[type="number"], input[type="text"] {
  font: inherit; color: var(--c-text); padding: 10px 12px;
  border: 1px solid var(--c-border); border-radius: var(--radius);
  background: var(--c-bg); width: 100%; transition: border-color .15s ease, box-shadow .15s ease;
}
select {
  appearance: none; -webkit-appearance: none; padding-right: 34px;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'><path d='M1 1l5 5 5-5' fill='none' stroke='%23637a5c' stroke-width='2' stroke-linecap='round'/></svg>");
  background-repeat: no-repeat; background-position: right 12px center;
}
select:focus, input:focus {
  outline: none; border-color: var(--c-accent);
  box-shadow: 0 0 0 3px rgba(74, 191, 126, .18);
}
.submit-field .btn { width: 100%; }
.form-hint { grid-column: 1 / -1; font-size: 13px; color: var(--c-muted); margin: 0; }

/* ---------------- 按钮 ---------------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  font: 600 15px var(--font-body); padding: 11px 20px; cursor: pointer;
  border: 1px solid transparent; border-radius: var(--radius);
  transition: transform .16s ease, box-shadow .16s ease, background .16s ease, color .16s ease, border-color .16s ease;
  user-select: none; text-decoration: none; line-height: 1.2;
}
.btn:hover { text-decoration: none; }
.btn:active { transform: translateY(1px) scale(.98); }
.btn-primary { background: var(--c-primary); color: #fff; box-shadow: 0 8px 18px -9px rgba(77, 176, 48, .75); }
.btn-primary:hover { background: #43a02b; transform: translateY(-1px); }
.btn-cta { background: var(--c-cta); color: #fff; box-shadow: 0 8px 18px -9px rgba(213, 42, 194, .7); }
.btn-cta:hover { background: #c025b0; transform: translateY(-1px); }
.btn-ghost { background: var(--c-surface); border-color: var(--c-border); color: var(--c-text); }
.btn-ghost:hover { border-color: var(--c-accent); color: var(--c-primary); }
.btn-lg { padding: 13px 24px; font-size: 16px; }
.btn[disabled] { opacity: .5; cursor: not-allowed; transform: none !important; }

.mini-btn {
  font: 600 12.5px var(--font-body); color: var(--c-muted); cursor: pointer;
  background: transparent; border: 1px solid var(--c-border); border-radius: 999px;
  padding: 3px 11px; transition: all .15s ease;
}
.mini-btn:hover { color: var(--c-cta); border-color: var(--c-cta); }

/* ---------------- 结果区 ---------------- */
.results { margin: 30px 0 40px; }
.results-toolbar { display: flex; align-items: flex-end; justify-content: space-between; gap: 16px; flex-wrap: wrap; margin-bottom: 18px; }
.results-title h2 { margin-bottom: 4px; }
.results-title h2 .count-badge {
  font: 700 13px var(--font-body); color: var(--c-cta); background: rgba(213, 42, 194, .08);
  border: 1px dashed rgba(213, 42, 194, .5); border-radius: 999px; padding: 3px 12px; vertical-align: 3px; margin-left: 6px;
}
.results-title .meta { margin: 0; color: var(--c-muted); font-size: 14px; }
.toolbar-actions { display: flex; gap: 10px; flex-wrap: wrap; }

.problems { display: grid; grid-template-columns: repeat(auto-fill, minmax(310px, 1fr)); gap: 18px; }
.problem-card {
  background: var(--c-surface); border: 1px solid var(--c-border);
  border-radius: var(--radius); box-shadow: var(--shadow-warm);
  overflow: hidden; display: flex; flex-direction: column;
  animation: fadeUp .55s both; position: relative;
}
.problem-card::before {
  content: ""; position: absolute; inset: 0; pointer-events: none; opacity: .4; z-index: 0;
  background: linear-gradient(180deg, rgba(240, 214, 170, .18), transparent 40%);
}
.problem-body { padding: 18px 18px 12px; position: relative; z-index: 1; flex: 1; }
.tags { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 12px; }
.chip {
  font-size: 12px; font-weight: 600; padding: 2px 10px; border-radius: 999px;
  border: 1px solid var(--c-border); color: var(--c-muted); background: var(--c-bg);
  letter-spacing: .5px;
}
.chip.grade { background: rgba(77, 176, 48, .1); color: var(--c-primary); border-color: rgba(77, 176, 48, .35); }
.chip.op { background: rgba(74, 191, 126, .1); color: #2f8f5e; border-color: rgba(74, 191, 126, .4); }
.chip.theme { background: rgba(213, 42, 194, .07); color: var(--c-cta); border-color: rgba(213, 42, 194, .3); }
.chip.diff { background: rgba(216, 162, 96, .12); color: #a5712a; border-color: rgba(216, 162, 96, .4); }

.q { font-family: var(--font-title); font-size: 16.5px; line-height: 1.85; margin: 0 0 12px; color: var(--c-text); }
.qno {
  display: inline-grid; place-items: center; min-width: 26px; height: 26px; padding: 0 4px;
  background: var(--c-primary); color: #fff; border-radius: 6px;
  font-family: var(--font-body); font-size: 13px; margin-right: 8px; vertical-align: 1px;
}

.answer { display: none; margin: 8px 0 4px; border-left: 3px solid var(--c-cta); background: rgba(213, 42, 194, .055); padding: 9px 13px; border-radius: 0 6px 6px 0; font-size: 14px; }
.answer.open { display: block; animation: pop .28s ease; }
.show-all-ans .answer { display: block; }
.ans-line { margin-bottom: 4px; }
.ans-line strong { color: var(--c-cta); font-size: 16px; }
.sol { color: var(--c-muted); font-size: 13.5px; line-height: 1.7; }

.problem-card .foot {
  display: flex; align-items: center; justify-content: space-between; gap: 10px;
  padding: 9px 14px; border-top: 1px dashed var(--c-border);
  background: linear-gradient(180deg, rgba(77, 176, 48, .08), rgba(74, 191, 126, .03));
  font-size: 12.5px; color: var(--c-muted); position: relative; z-index: 1;
}
.foot-idx { letter-spacing: .5px; }

.results-foot { margin-top: 20px; }
.hint { color: var(--c-muted); font-size: 14px; background: rgba(74, 191, 126, .07); border: 1px dashed rgba(74, 191, 126, .4); border-radius: var(--radius); padding: 12px 16px; }

/* ---------------- 在线练习 ---------------- */
.practice { padding: 34px 0 50px; max-width: 720px; margin: 0 auto; }
.practice-empty { padding: 46px 30px; text-align: center; }
.practice-empty h2 { font-family: var(--font-title); margin: 0 0 8px; }
.practice-empty p { color: var(--c-muted); margin: 0 0 20px; }
.quiz-top { display: flex; flex-direction: column; gap: 10px; margin-bottom: 16px; }
.quiz-meta { display: flex; justify-content: space-between; font-weight: 600; color: var(--c-muted); font-size: 14px; }
.quiz-meta b { color: var(--c-text); }
.progress { height: 8px; border-radius: 999px; background: var(--c-border); overflow: hidden; }
.progress > i { display: block; height: 100%; width: 0; border-radius: 999px; background: linear-gradient(90deg, var(--c-primary), var(--c-accent)); transition: width .4s ease; }

.quiz-card { padding: 26px 26px 22px; }
.quiz-card .bigq { font-size: 19px; margin-bottom: 16px; }
.answer-input { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.answer-input input {
  flex: 1; min-width: 160px; font-size: 22px; font-family: var(--font-title);
  padding: 12px 14px; border: 1.6px solid var(--c-border); border-radius: var(--radius);
}
.answer-input input:focus { border-color: var(--c-cta); box-shadow: 0 0 0 3px rgba(213, 42, 194, .14); }
.unit { font-size: 17px; font-weight: 600; color: var(--c-muted); }
.input-hint { width: 100%; margin: 6px 0 0; font-size: 13px; color: var(--c-muted); }
.quiz-nav { display: flex; gap: 12px; margin-top: 18px; flex-wrap: wrap; }
.quiz-nav .btn:last-child { margin-left: auto; }

/* 得分卡 */
.score-card { padding: 34px 28px; text-align: center; }
.score-head { display: flex; align-items: center; justify-content: center; gap: 26px; flex-wrap: wrap; margin-bottom: 20px; }
.score-ring {
  width: 132px; height: 132px; border-radius: 50%; position: relative;
  display: grid; place-items: center;
  background: conic-gradient(var(--c-primary) var(--pct, 0%), var(--c-border) 0);
}
.score-ring::before { content: ""; position: absolute; inset: 12px; background: var(--c-surface); border-radius: 50%; }
.score-ring b { position: relative; font-family: var(--font-title); font-size: 30px; color: var(--c-text); }
.score-info { text-align: left; }
.score-info h2 { font-family: var(--font-title); margin: 0 0 6px; font-size: 22px; }
.score-info p { margin: 4px 0; color: var(--c-muted); }
.score-info .praise { color: var(--c-primary); font-weight: 700; }

.review-list { margin-top: 22px; text-align: left; display: grid; gap: 12px; }
.review-item {
  border: 1px solid var(--c-border); border-radius: var(--radius);
  padding: 14px 16px; background: var(--c-bg); position: relative;
}
.review-item.ok { border-left: 4px solid var(--c-primary); }
.review-item.bad { border-left: 4px solid var(--c-cta); }
.review-head { display: flex; gap: 10px; align-items: flex-start; }
.rv-mark {
  width: 24px; height: 24px; border-radius: 50%; flex: none;
  display: grid; place-items: center; font-size: 14px; font-weight: 900; color: #fff;
}
.review-item.ok .rv-mark { background: var(--c-primary); }
.review-item.bad .rv-mark { background: var(--c-cta); }
.review-q { font-family: var(--font-title); font-size: 15.5px; line-height: 1.7; }
.review-ans { margin: 8px 0 6px; font-size: 14px; color: var(--c-muted); }
.review-ans b { color: var(--c-text); }
.review-item .answer { margin: 6px 0 0; }
.score-actions { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; margin-top: 22px; }

/* ---------------- 打印预览 ---------------- */
.print-bar { display: flex; align-items: center; justify-content: space-between; gap: 14px; flex-wrap: wrap; padding: 26px 0 6px; }
.print-bar > div { display: flex; gap: 10px; flex-wrap: wrap; }
.print-tip { color: var(--c-muted); font-size: 13px; margin: 0; }
.sheet-holder { padding: 26px 0 60px; }
.sheet {
  background: var(--c-surface); color: #1a1a1a;
  max-width: 820px; margin: 0 auto; padding: 34px 38px;
  border: 1px solid var(--c-border); border-radius: var(--radius);
  box-shadow: var(--shadow-warm);
  -webkit-print-color-adjust: exact; print-color-adjust: exact;
}
.print-head { display: flex; align-items: flex-end; justify-content: space-between; gap: 14px; flex-wrap: wrap; border-bottom: 2.4px solid #1a1a1a; padding-bottom: 12px; margin-bottom: 12px; }
.print-brand { font-family: var(--font-title); font-size: 25px; font-weight: 900; letter-spacing: 2px; }
.print-blanks { display: flex; gap: 26px; font-size: 13.5px; color: #333; }
.print-blanks span { border-bottom: 1px solid #999; padding-bottom: 2px; min-width: 96px; display: inline-block; }
.print-meta { display: flex; gap: 8px 22px; flex-wrap: wrap; font-size: 13px; color: #444; margin-bottom: 14px; }
.print-meta .sep { color: #bbb; }
.print-problems { display: grid; grid-template-columns: 1fr 1fr; gap: 0 28px; }
@media (max-width: 620px) { .print-problems { grid-template-columns: 1fr; } }
.pitem {
  display: flex; gap: 8px; padding: 9px 2px; border-bottom: 1px dotted #ccc;
  min-height: 62px; break-inside: avoid; font-size: 14.5px; line-height: 1.7;
}
.pno { font-weight: 800; color: var(--c-primary); flex: none; }
.cutline { display: flex; align-items: center; gap: 12px; margin: 20px 0 8px; color: var(--c-muted); font-size: 12.5px; letter-spacing: 2px; }
.cutline::before, .cutline::after { content: ""; flex: 1; border-top: 1.4px dashed #bbb; }
.print-answers {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: 7px 18px; font-size: 13.5px; color: #333;
}
.print-answers span { padding: 6px 8px; border-radius: 6px; background: #f2f6f0; border: 1px solid #e3eadf; }
.print-answers b { color: var(--c-cta); }
.print-foot { margin-top: 22px; font-size: 12px; color: #888; text-align: right; letter-spacing: 1px; }

/* ---------------- 页脚 ---------------- */
.site-footer { border-top: 1px solid var(--c-border); padding: 26px 0 34px; margin-top: 10px; text-align: center; background: rgba(255, 255, 255, .4); }
.site-footer p { margin: 4px 0; color: var(--c-text); font-family: var(--font-title); letter-spacing: 1px; }
.site-footer .foot-note { color: var(--c-muted); font-family: var(--font-body); font-size: 13px; }

/* ---------------- 动画 ---------------- */
@keyframes fadeUp { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: none; } }
@keyframes pop { from { opacity: 0; transform: translateY(-5px); } to { opacity: 1; transform: none; } }
.fade-in { animation: fadeUp .5s both; }

:focus-visible { outline: 2px solid var(--c-cta); outline-offset: 2px; border-radius: 4px; }

/* ---------------- 响应式 ---------------- */
@media (max-width: 860px) {
  .hero { grid-template-columns: 1fr; gap: 26px; padding-top: 30px; }
  .hero-photo { height: 250px; }
  .grid-form { grid-template-columns: repeat(2, 1fr); }
  .submit-field { grid-column: 1 / -1; }
  .header-inner { justify-content: center; }
}
@media (max-width: 520px) {
  .grid-form { grid-template-columns: 1fr; }
  .panel { padding: 20px 16px; }
  .quiz-card { padding: 20px 16px; }
  .pola { width: 160px; }
  .hero-photo { height: 220px; }
}

/* ---------------- 打印样式（试卷输出） ---------------- */
@media print {
  @page { size: A4; margin: 13mm 12mm; }
  body { background: #fff !important; -webkit-print-color-adjust: exact; print-color-adjust: exact; }
  .grain, .vignette, .warm { display: none !important; }
  .site-header, .site-footer, .print-bar { display: none !important; }
  .sheet-holder { padding: 0; }
  .sheet { border: none; box-shadow: none; max-width: none; padding: 0; border-radius: 0; }
  .qno { -webkit-print-color-adjust: exact; print-color-adjust: exact; }
  .answer, .answer.open { display: block !important; }
}