/* 刷题包「功能介绍」页样式 —— 叠在 guide.css 之上（导航 / 页脚 / 按钮 / FAQ / 相关阅读沿用那一份）。
   每页一个主色（body[data-accent]），截图全部是 App 的真实运行画面（scripts/capture-features.cjs 生成）。 */
body.f-page{--acc:#5f9bf7;--acc-2:#5c8af0;--acc-ink:#3a58ab;--acc-soft:#eef3fb;--acc-line:#c3d9fb;--panel-a:#dbe9fe;--panel-b:#f4f8ff;--glow-a:rgba(95,155,247,.28);--glow-b:rgba(124,107,247,.20);overflow-x:hidden}
body.f-page[data-accent=violet]{--acc:#7c6bf7;--acc-2:#6366f1;--acc-ink:#4c3fc4;--acc-soft:#f2f0ff;--acc-line:#d9d3ff;--panel-a:#e3deff;--panel-b:#f8f6ff;--glow-a:rgba(124,107,247,.30);--glow-b:rgba(95,155,247,.22)}
body.f-page[data-accent=clay]{--acc:#c8643c;--acc-2:#b4532d;--acc-ink:#8f3f1f;--acc-soft:#fbf1ea;--acc-line:#efd3c2;--panel-a:#f5e2d2;--panel-b:#fdf8f2;--glow-a:rgba(200,100,60,.22);--glow-b:rgba(232,170,88,.22)}
body.f-page[data-accent=emerald]{--acc:#0f9f7a;--acc-2:#0b8a69;--acc-ink:#0a6b52;--acc-soft:#ebf8f3;--acc-line:#bfe8d9;--panel-a:#d5f1e6;--panel-b:#f3fbf8;--glow-a:rgba(15,159,122,.22);--glow-b:rgba(95,155,247,.20)}
body.f-page[data-accent=rose]{--acc:#8b6cf0;--acc-2:#d9608f;--acc-ink:#5a3fc0;--acc-soft:#f6f0fd;--acc-line:#e2d3f7;--panel-a:#ecdcfb;--panel-b:#fdf6fa;--glow-a:rgba(139,108,240,.26);--glow-b:rgba(232,120,160,.22)}

.f-main{padding-top:0}
.f-sec{padding:72px 0}
.f-sec.alt{background:#fff;border-block:1px solid var(--brand-50)}
.f-sec.tight{padding:48px 0}
@media(max-width:640px){.f-sec{padding:52px 0}.f-sec.tight{padding:36px 0}}
.f-head{max-width:44rem;margin:0 auto 44px;text-align:center}
.f-head.left{margin-left:0;text-align:left}
.f-eyebrow{display:block;font-size:13px;font-weight:700;letter-spacing:.14em;color:var(--acc-ink);margin:0 0 12px}
.f-head h2,.f-copy h2{font-size:clamp(26px,3.6vw,36px);line-height:1.28;font-weight:900;letter-spacing:-.01em;margin:0;text-wrap:balance}
.f-head p{margin:16px 0 0;color:var(--slate-600);font-size:16.5px;line-height:1.85}

/* ── 手机外框（截图自带状态栏和灵动岛，外框只做一圈深色边 + 圆角） ── */
.dev{--w:260px;position:relative;flex-shrink:0;width:var(--w);margin:0;padding:calc(var(--w)*.028);border-radius:calc(var(--w)*.165);background:linear-gradient(160deg,#2a2f3a,#0d1017 45%,#1a1e27);box-shadow:0 40px 70px -28px rgba(30,45,79,.5),0 12px 24px -12px rgba(30,45,79,.25),inset 0 0 0 1px rgba(255,255,255,.1)}
.dev::after{content:"";position:absolute;inset:0;border-radius:inherit;pointer-events:none;box-shadow:inset 0 1px 0 rgba(255,255,255,.18)}
.dev img{display:block;width:100%;height:auto;border-radius:calc(var(--w)*.135);background:#eef3fb;cursor:zoom-in}
.shot-fig{margin:0;display:flex;flex-direction:column;align-items:center;gap:14px;min-width:0}
.shot-fig figcaption{font-size:13px;line-height:1.55;color:var(--slate-500);text-align:center;max-width:17rem}
.shot-fig figcaption b{color:var(--slate-700);font-weight:700}

/* ── 首屏 ── */
.f-hero{position:relative;padding:128px 0 56px;overflow:hidden}
.f-hero::before{content:"";position:absolute;z-index:0;top:-180px;right:-140px;width:620px;height:620px;border-radius:50%;background:var(--glow-a);filter:blur(90px)}
.f-hero::after{content:"";position:absolute;z-index:0;top:240px;left:-200px;width:480px;height:480px;border-radius:50%;background:var(--glow-b);filter:blur(90px)}
.f-hero-grid{position:relative;z-index:1;display:grid;gap:44px;align-items:center}
@media(min-width:1024px){.f-hero{padding:150px 0 76px}.f-hero-grid{grid-template-columns:minmax(0,1.02fr) minmax(0,1fr);gap:28px}}
.f-kicker{display:inline-flex;align-items:center;gap:8px;font-size:12.5px;font-weight:700;color:var(--acc-ink);background:#fff;border:1px solid var(--acc-line);border-radius:999px;padding:6px 14px;margin:0 0 20px;box-shadow:var(--shadow-soft)}
.f-kicker i{width:8px;height:8px;border-radius:50%;background:var(--acc);box-shadow:0 0 0 4px var(--acc-soft)}
.f-hero h1{font-size:clamp(31px,5vw,50px);line-height:1.18;font-weight:900;letter-spacing:-.02em;margin:0 0 20px;text-wrap:balance}
.f-hero h1 em{display:block;font-style:normal;background:linear-gradient(90deg,var(--acc),var(--acc-2));-webkit-background-clip:text;background-clip:text;color:transparent}
.f-lead{font-size:17.5px;line-height:1.85;color:var(--slate-600);margin:0 0 26px;max-width:35rem}
.f-hero .g-actions{margin-bottom:22px}
.f-hero .btn-primary{background:linear-gradient(135deg,var(--acc),var(--acc-2));box-shadow:0 14px 34px -10px var(--glow-a)}
.f-hero .btn-primary:hover{filter:brightness(1.05)}
.f-points{list-style:none;padding:0;margin:0;display:flex;flex-wrap:wrap;gap:10px 22px;font-size:14px;color:var(--slate-600)}
.f-points li{display:inline-flex;align-items:center;gap:7px}
.f-points svg{width:16px;height:16px;color:var(--acc);flex-shrink:0}
.f-hero-meta{margin:22px 0 0;font-size:12.5px;color:var(--slate-500)}

.f-stack{position:relative;display:flex;justify-content:center;align-items:flex-end;padding:8px 0 4px}
.f-stack .dev{--w:clamp(150px,40vw,250px)}
.f-stack .dev:nth-child(1){z-index:1;margin-right:calc(var(--w)*-.36);transform:rotate(-6deg) translateY(4%);--w:clamp(126px,34vw,214px)}
.f-stack .dev:nth-child(2){z-index:2}
.f-stack .dev:nth-child(3){z-index:1;margin-left:calc(var(--w)*-.36);transform:rotate(6deg) translateY(4%);--w:clamp(126px,34vw,214px)}
.f-stack.two .dev:nth-child(1){transform:rotate(-5deg) translateY(3%);margin-right:calc(var(--w)*-.2)}
.f-stack.two .dev:nth-child(2){transform:rotate(3deg)}
@media(min-width:1024px){.f-stack{justify-content:flex-end;padding-right:6px}.f-stack .dev{--w:262px}.f-stack .dev:nth-child(1),.f-stack .dev:nth-child(3){--w:222px}}

/* ── 数字条 ── */
.f-stats{position:relative;z-index:1;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:1px;background:var(--acc-line);border:1px solid var(--acc-line);border-radius:22px;overflow:hidden;box-shadow:var(--shadow-soft);margin-top:40px}
@media(min-width:768px){.f-stats{grid-template-columns:repeat(4,minmax(0,1fr))}}
.f-stats div{background:#fff;padding:22px 18px;text-align:center}
.f-stats b{display:block;font-size:26px;line-height:1.2;font-weight:900;letter-spacing:-.01em;color:var(--ink)}
.f-stats b small{font-size:14px;font-weight:700;margin-left:2px;color:var(--slate-600)}
.f-stats span{display:block;margin-top:6px;font-size:13px;color:var(--slate-500);line-height:1.5}

/* ── 图文交替 ── */
.f-row{display:grid;gap:36px;align-items:center}
.f-row+.f-row{margin-top:88px}
@media(max-width:640px){.f-row+.f-row{margin-top:60px}}
@media(min-width:960px){.f-row{grid-template-columns:minmax(0,1fr) minmax(0,1.06fr);gap:64px}.f-row.rev .f-copy{order:2}.f-row.rev .f-media{order:1}}
.f-num{display:inline-flex;align-items:center;gap:10px;font-size:13px;font-weight:800;letter-spacing:.12em;color:var(--acc-ink);margin:0 0 14px}
.f-num::before{content:"";width:28px;height:3px;border-radius:99px;background:linear-gradient(90deg,var(--acc),var(--acc-2))}
.f-copy>p{margin:16px 0 0;color:var(--slate-600);font-size:16.5px;line-height:1.9}
.f-copy>p strong,.f-list strong{color:var(--ink)}
.f-list{list-style:none;padding:0;margin:22px 0 0;display:grid;gap:13px}
.f-list li{position:relative;padding-left:32px;color:var(--slate-700);font-size:15.5px;line-height:1.75}
.f-list li::before{content:"";position:absolute;left:0;top:4px;width:20px;height:20px;border-radius:50%;background:var(--acc-soft) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%231e2d4f' stroke-width='3.2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='20 6 9 17 4 12'/%3E%3C/svg%3E") center/11px no-repeat;border:1px solid var(--acc-line)}
.f-copy .f-note{margin-top:20px;font-size:13.5px;color:var(--slate-500);line-height:1.7;padding:12px 14px;border-radius:12px;background:var(--acc-soft);border:1px solid var(--acc-line)}
.f-copy .f-link{display:inline-flex;align-items:center;gap:6px;margin-top:20px;font-weight:700;color:var(--acc-ink)}
.f-copy .f-link svg{width:16px;height:16px}
.f-panel{position:relative;border-radius:32px;padding:40px 20px 34px;display:flex;justify-content:center;align-items:flex-start;gap:clamp(12px,3vw,28px);overflow:hidden;border:1px solid rgba(255,255,255,.85);box-shadow:var(--shadow-soft);background:radial-gradient(60% 45% at 12% 4%,var(--glow-a),transparent 70%),radial-gradient(50% 40% at 94% 22%,var(--glow-b),transparent 70%),linear-gradient(180deg,var(--panel-a),var(--panel-b))}
.f-panel .dev{--w:clamp(132px,38vw,236px)}
.f-panel.one .dev{--w:clamp(190px,58vw,266px)}
.f-panel.dark{background:radial-gradient(60% 45% at 12% 4%,rgba(95,155,247,.32),transparent 70%),radial-gradient(50% 40% at 94% 22%,rgba(216,178,110,.18),transparent 70%),linear-gradient(180deg,#141c33,#0c1020);border-color:rgba(255,255,255,.08)}
.f-panel.dark figcaption{color:rgba(255,255,255,.72)}.f-panel.dark figcaption b{color:#fff}
@media(max-width:480px){.f-panel{padding:26px 12px 24px;border-radius:24px}.shot-fig figcaption{font-size:12px}}

/* ── 电脑 / 平板窗口 ── */
.win{margin:0;overflow:hidden;border-radius:18px;background:#fff;box-shadow:0 50px 90px -40px rgba(30,45,79,.45),0 0 0 1px rgba(30,45,79,.07)}
.win-bar{display:flex;align-items:center;gap:7px;height:38px;padding:0 14px;background:linear-gradient(#f8fafd,#eef2f8);border-bottom:1px solid #e3e9f3}
.win-bar i{width:11px;height:11px;border-radius:50%;display:block}
.win-bar span{flex:1;text-align:center;margin-right:47px;font-size:12px;color:#64748b;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.win img{display:block;width:100%;height:auto;cursor:zoom-in}
.win-cap{margin:14px 0 0;text-align:center;font-size:13px;color:var(--slate-500)}

/* ── 卡片格 ── */
.f-cards{display:grid;gap:18px;grid-template-columns:1fr}
@media(min-width:600px){.f-cards{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(min-width:940px){.f-cards{grid-template-columns:repeat(3,minmax(0,1fr))}}
.f-card{background:#fff;border:1px solid var(--brand-50);border-radius:22px;padding:26px 24px;box-shadow:var(--shadow-soft);transition:border-color .2s,transform .2s}
.f-sec.alt .f-card{background:var(--mist);box-shadow:none;border-color:#e6edf9}
.f-card:hover{border-color:var(--acc-line);transform:translateY(-2px)}
.f-card .ico{width:46px;height:46px;border-radius:14px;display:flex;align-items:center;justify-content:center;background:var(--acc-soft);color:var(--acc-ink);border:1px solid var(--acc-line);margin-bottom:16px}
.f-card .ico svg{width:22px;height:22px}
.f-card h3{margin:0 0 8px;font-size:17px;font-weight:800;line-height:1.4}
.f-card p{margin:0;font-size:14.5px;line-height:1.8;color:var(--slate-600)}

/* ── 步骤 ── */
.f-steps{list-style:none;counter-reset:fs;padding:0;margin:0;display:grid;gap:18px;grid-template-columns:repeat(auto-fit,minmax(220px,1fr))}
.f-steps li{counter-increment:fs;position:relative;background:#fff;border:1px solid var(--brand-50);border-radius:22px;padding:58px 22px 24px;box-shadow:var(--shadow-soft)}
.f-sec.alt .f-steps li{background:var(--mist);box-shadow:none;border-color:#e6edf9}
.f-steps li::before{content:counter(fs);position:absolute;left:22px;top:20px;width:30px;height:30px;border-radius:10px;display:flex;align-items:center;justify-content:center;font-weight:900;font-size:15px;color:#fff;background:linear-gradient(135deg,var(--acc),var(--acc-2));box-shadow:0 8px 20px -6px var(--glow-a)}
.f-steps strong{display:block;font-size:16.5px;font-weight:800;margin:0 0 6px;color:var(--ink)}
.f-steps p{margin:0;font-size:14.5px;line-height:1.8;color:var(--slate-600)}

/* ── 表格 ── */
.f-table{width:100%;border-collapse:separate;border-spacing:0;font-size:14.5px;background:#fff;border:1px solid var(--acc-line);border-radius:18px;overflow:hidden;box-shadow:var(--shadow-soft)}
.f-table th{background:var(--acc-soft);color:var(--ink);font-weight:800;text-align:left;padding:13px 16px;border-bottom:1px solid var(--acc-line);white-space:nowrap}
.f-table td{padding:13px 16px;border-bottom:1px solid #eef2f8;vertical-align:top;color:var(--slate-700);line-height:1.7}
.f-table tr:last-child td{border-bottom:0}.f-table td:first-child{font-weight:700;color:var(--ink)}
.f-table-wrap{overflow-x:auto;-webkit-overflow-scrolling:touch}
.f-table-note{margin:14px 2px 0;font-size:13px;color:var(--slate-500);line-height:1.7}
@media(max-width:640px){.f-table{font-size:13px}.f-table th,.f-table td{padding:10px 11px}.f-table th{white-space:normal}}

/* ── 截图带（横向三四张） ── */
.f-strip{display:grid;gap:clamp(14px,3vw,30px);grid-template-columns:repeat(2,minmax(0,1fr));justify-items:center}
@media(min-width:860px){.f-strip{grid-template-columns:repeat(var(--n,4),minmax(0,1fr))}}
.f-strip .dev{--w:clamp(138px,40vw,224px)}

/* ── 主题切换器 ── */
.tsw{border-radius:34px;padding:28px 18px 34px;transition:background .5s ease,color .3s ease;border:1px solid rgba(255,255,255,.7);box-shadow:var(--shadow-soft);background:linear-gradient(180deg,#dbe9fe,#f4f8ff);color:var(--ink)}
@media(min-width:768px){.tsw{padding:38px 40px 46px}}
.tsw[data-t=eyecare]{background:linear-gradient(180deg,#dfe7d6,#f3f0e4)}
.tsw[data-t=cream]{background:linear-gradient(180deg,#f0dccb,#fbf4ea)}
.tsw[data-t=glass]{background:radial-gradient(60% 50% at 10% 0,#bcd6ff,transparent 70%),radial-gradient(55% 45% at 100% 10%,#dccfff,transparent 70%),radial-gradient(60% 50% at 90% 100%,#f8d5e2,transparent 70%),#eef2fd}
.tsw[data-t=dark]{background:linear-gradient(180deg,#0f1a33,#1b2a4e);color:#fff;border-color:rgba(255,255,255,.08)}
.tsw[data-t=obsidian]{background:radial-gradient(60% 45% at 80% 0,rgba(216,178,110,.22),transparent 70%),linear-gradient(180deg,#0b0b0e,#1a1712);color:#fff;border-color:rgba(216,178,110,.18)}
.tsw-tabs{display:flex;flex-wrap:wrap;justify-content:center;gap:8px;margin:0 0 30px}
.tsw-tabs button{display:inline-flex;align-items:center;gap:8px;border:1px solid rgba(30,45,79,.1);background:rgba(255,255,255,.72);color:#1e2d4f;font:inherit;font-size:14px;font-weight:700;padding:8px 15px 8px 9px;border-radius:999px;cursor:pointer;transition:transform .15s,box-shadow .2s,background .2s;-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px)}
.tsw-tabs button i{width:22px;height:22px;border-radius:50%;background:linear-gradient(135deg,var(--c1) 50%,var(--c2) 50%);border:2px solid #fff;box-shadow:0 0 0 1px rgba(30,45,79,.14)}
.tsw-tabs button:hover{transform:translateY(-1px)}
.tsw-tabs button[aria-selected=true]{background:#1e2d4f;color:#fff;border-color:#1e2d4f;box-shadow:0 10px 24px -8px rgba(30,45,79,.5)}
.tsw[data-t=dark] .tsw-tabs button[aria-selected=true],.tsw[data-t=obsidian] .tsw-tabs button[aria-selected=true]{background:#fff;color:#1e2d4f;border-color:#fff}
.tsw-stage{display:grid;gap:26px;align-items:center;justify-items:center}
@media(min-width:900px){.tsw-stage{grid-template-columns:minmax(0,1fr) auto;gap:40px;justify-items:start}}
.tsw-info{max-width:26rem;text-align:center}
@media(min-width:900px){.tsw-info{text-align:left}}
.tsw-info h3{margin:0 0 10px;font-size:clamp(24px,3vw,30px);font-weight:900;letter-spacing:-.01em}
.tsw-info p{margin:0;font-size:15.5px;line-height:1.85;opacity:.82}
.tsw-info .tsw-tags{display:flex;flex-wrap:wrap;gap:8px;margin-top:16px;justify-content:center}
@media(min-width:900px){.tsw-info .tsw-tags{justify-content:flex-start}}
.tsw-info .tsw-tags span{font-size:12.5px;font-weight:600;padding:4px 11px;border-radius:999px;background:rgba(255,255,255,.6);border:1px solid rgba(30,45,79,.1)}
.tsw[data-t=dark] .tsw-tags span,.tsw[data-t=obsidian] .tsw-tags span{background:rgba(255,255,255,.1);border-color:rgba(255,255,255,.16)}
.tsw-phones{display:flex;gap:clamp(12px,3vw,26px);justify-content:center}
.tsw-phones .dev{--w:clamp(136px,39vw,232px)}
.tsw-phones img{transition:opacity .25s ease}
.tsw-phones img.swap{opacity:.25}

/* ── 六套主题卡片 ── */
.th-grid{display:grid;gap:20px;grid-template-columns:repeat(2,minmax(0,1fr))}
@media(min-width:900px){.th-grid{grid-template-columns:repeat(3,minmax(0,1fr));gap:26px}}
.th-card{margin:0;border-radius:26px;padding:22px 16px 20px;text-align:center;border:1px solid rgba(30,45,79,.07);box-shadow:var(--shadow-soft);display:flex;flex-direction:column;align-items:center}
.th-card .dev{--w:clamp(120px,34vw,196px);margin-top:16px}
.th-card h3{margin:0;font-size:18px;font-weight:900}
.th-card p{margin:6px 0 0;font-size:13px;line-height:1.6;opacity:.78;min-height:2.9em}
.th-card.on-dark{color:#fff;border-color:rgba(255,255,255,.08)}

/* ── 色块 ── */
.swatches{display:flex;flex-wrap:wrap;gap:14px 18px;margin-top:22px}
.swatches span{display:flex;flex-direction:column;align-items:center;gap:7px;font-size:12.5px;color:var(--slate-600);font-weight:600}
.swatches i{width:44px;height:44px;border-radius:50%;background:var(--c);border:3px solid #fff;box-shadow:0 0 0 1px rgba(30,45,79,.14),0 6px 14px -6px rgba(30,45,79,.25)}

/* ── FAQ / 相关 / 更多功能 ── */
.f-faq{max-width:50rem;margin:0 auto}
.f-faq .faq details{border-color:#e6edf9;border-radius:16px;box-shadow:var(--shadow-soft)}
.f-faq .faq summary{padding:17px 20px;font-size:15.5px}
.f-faq .faq .a{padding:14px 20px 18px;line-height:1.85}
.f-more{display:grid;gap:16px;grid-template-columns:repeat(auto-fit,minmax(212px,1fr))}
.f-more a{position:relative;display:flex;flex-direction:column;gap:6px;background:#fff;border:1px solid var(--brand-50);border-radius:20px;padding:20px 20px 18px;color:var(--ink);box-shadow:var(--shadow-soft);transition:transform .2s,border-color .2s,box-shadow .2s}
.f-more a:hover{transform:translateY(-3px);border-color:var(--brand-200);box-shadow:var(--shadow-lift)}
.f-more .k{font-size:11.5px;font-weight:700;letter-spacing:.06em;color:var(--brand-600)}
.f-more .t{font-size:16px;font-weight:800;line-height:1.45}
.f-more .d{font-size:13.5px;color:var(--slate-500);line-height:1.6}
.f-guides{margin:26px 0 0;font-size:14.5px;color:var(--slate-600);line-height:2}
.f-guides a{font-weight:600}
.f-cta{padding:0 0 72px}
.f-cta .g-bottom{margin:0}

/* ── 点开放大 ── */
.lb{position:fixed;inset:0;z-index:100;display:none;align-items:center;justify-content:center;padding:24px;background:rgba(12,18,34,.82);-webkit-backdrop-filter:blur(6px);backdrop-filter:blur(6px);cursor:zoom-out}
.lb.open{display:flex}
.lb img{max-width:100%;max-height:100%;border-radius:22px;box-shadow:0 30px 80px rgba(0,0,0,.5)}
.lb button{position:absolute;top:16px;right:16px;width:42px;height:42px;border-radius:50%;border:0;background:rgba(255,255,255,.16);color:#fff;font-size:24px;line-height:1;cursor:pointer}

@media(prefers-reduced-motion:reduce){.tsw,.tsw-phones img,.f-card,.f-more a{transition:none}}