/* Unit 1, Lesson 4: check diagram, rails calculator, pick-the-rail game. */
.mm-bill { animation: mm-fly 3s ease-in-out infinite; }
@keyframes mm-fly { 0% { translate: -70px 50px; opacity: 0; } 15% { opacity: 1; } 50% { translate: 0 0; } 85% { opacity: 1; } 100% { translate: 70px 50px; opacity: 0; } }
.mm-bee { animation: mm-buzz 2.4s ease-in-out infinite alternate; }
.mm-bee.b2 { animation-duration: 3s; animation-direction: alternate-reverse; }
.mm-bee.b3 { animation-duration: 2s; }
@keyframes mm-buzz { to { translate: 60px 12px; } }
.split-msg[data-tone="good"], .fd-why[data-tone="good"] { border-color: var(--good); }
.split-msg[data-tone="warn"], .fd-why[data-tone="warn"] { border-color: var(--wants); }
.md-card { background: var(--card); border-radius: 24px; padding: clamp(18px, 3.5vw, 30px); box-shadow: 0 1px 0 var(--line), 0 24px 50px -30px rgba(60, 50, 30, .25); margin-top: 20px; }
.md-card .split-msg { margin: 16px 0 0; font-size: 17px; line-height: 1.55; padding-left: 14px; border-left: 4px solid var(--line); }
.md-lab { display: block; font-size: 15px; color: var(--ink-2); margin: 0 0 8px; }
.md-lab b { color: var(--ink); }
.rt-chips { display: flex; flex-wrap: wrap; gap: 8px; }
.oa-ic { display: inline-grid; place-items: center; width: 40px; height: 40px; border-radius: 12px; background: color-mix(in srgb, var(--accent) 14%, transparent); color: var(--accent); flex: none; }
.oa-ic svg { width: 22px; height: 22px; }
.mt-key { display: flex; flex-wrap: wrap; gap: 6px 18px; margin-top: 12px; font-size: 14px; color: var(--ink-2); }
.mt-key span { display: inline-flex; align-items: center; gap: 6px; }
.mt-key i { display: inline-block; width: 14px; height: 14px; border-radius: 4px; }
.neg { color: var(--wants); }
.ok { color: var(--good); }
.fd { margin-top: 28px; background: var(--card); border-radius: 24px; padding: clamp(16px, 3vw, 28px); box-shadow: 0 1px 0 var(--line), 0 24px 50px -30px rgba(60, 50, 30, .25); }
.fd-top { display: flex; justify-content: space-between; gap: 16px 24px; align-items: flex-start; padding-bottom: 16px; border-bottom: 1px solid var(--line); }
.fd-top small, .pg-score small { display: block; font-size: 12px; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; color: var(--ink-3); }
.fd-top > div > b { display: block; margin-top: 6px; font-family: var(--serif); font-weight: 500; font-size: clamp(20px, 2.4vw, 24px); line-height: 1.35; }
.pg-score { text-align: right; flex: none; }
.pg-score b { font-family: var(--serif); font-weight: 500; font-size: 26px; color: var(--good); font-variant-numeric: tabular-nums; }
.pg-score b.neg { color: var(--wants); }
.fd-grid { display: grid; grid-template-columns: minmax(0, 340px) minmax(0, 1fr); gap: 28px; margin-top: 22px; align-items: start; }
.fd-phone { background: var(--ink); border-radius: 34px; padding: 12px; box-shadow: 0 20px 40px -24px rgba(0, 0, 0, .45); }
.fd-screen { background: var(--paper); border-radius: 24px; padding: 18px 18px 14px; min-height: 330px; animation: fd-in .4s var(--ease); }
.fd-bar { display: flex; justify-content: space-between; align-items: baseline; gap: 10px; margin-bottom: 16px; }
.fd-bar b { font-family: var(--serif); font-weight: 500; font-size: 19px; color: #2f7a55; }
.fd-bar span { font-size: 12.5px; color: var(--ink-3); text-align: right; }
.fd-alert { background: color-mix(in srgb, var(--wants) 16%, transparent); color: var(--wants); font-weight: 700; font-size: 14px; border-radius: 10px; padding: 8px 10px; margin-bottom: 12px; }
.fd-screen > small { font-size: 12px; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; color: var(--ink-3); }
.fd-avail { font-family: var(--serif); font-size: 44px; line-height: 1.1; margin: 2px 0 12px; font-variant-numeric: tabular-nums; }
.fd-line { display: flex; justify-content: space-between; gap: 12px; padding: 8px 0; border-top: 1px solid var(--line); font-size: 14px; }
.fd-line span { color: var(--ink-2); }
.fd-line b { font-variant-numeric: tabular-nums; white-space: nowrap; }
.fd-line.pend span, .fd-line.pend b { color: var(--wants); }
.fd-sw { font-size: 12.5px; padding: 2px 10px; border-radius: 99px; background: var(--paper-2); color: var(--ink-2); }
.fd-sw.on { background: var(--accent); color: var(--on-color); }
.fd-scene { margin: 0 0 16px; font-size: 18px; line-height: 1.55; }
.fd-opts { display: grid; gap: 8px; }
.fd-opt { font: inherit; font-size: 16px; text-align: left; color: var(--ink); background: var(--paper-2); border: 1.5px solid transparent; border-radius: 14px; padding: 12px 14px; cursor: pointer; transition: border-color .2s, background .2s; }
.fd-opt:hover:not(:disabled) { border-color: var(--ink-3); }
.fd-opt:disabled { cursor: default; }
.fd-opt.right { border-color: var(--good); background: color-mix(in srgb, var(--good) 14%, var(--card)); }
.fd-opt.wrong { border-color: var(--wants); background: color-mix(in srgb, var(--wants) 10%, var(--card)); }
.fd-opt.alt { border-color: color-mix(in srgb, var(--good) 50%, transparent); border-style: dashed; }
.fd-opt:disabled:not(.right):not(.wrong):not(.alt) { opacity: .55; }
.fd-why { margin-top: 16px; font-size: 16px; line-height: 1.55; padding-left: 14px; border-left: 4px solid var(--line); }
.fd-next { margin-top: 16px; width: 100%; justify-content: center; }
.fd-next:disabled { opacity: .5; cursor: default; }
#rr-result { margin-top: 8px; }
.rd-cmp { margin: 12px 0 0; display: grid; gap: 4px; max-width: 620px; }
.rd-cmp div { display: flex; justify-content: space-between; gap: 12px; border-top: 1px solid var(--line); padding-top: 6px; font-size: 15px; }
.rd-cmp dt { color: var(--ink-2); }
.rd-cmp dd { margin: 0; font-weight: 700; text-align: right; }
.rd-cmp dd.ok { color: var(--good); }
.rd-cmp dd.no { color: var(--wants); }
.mm-two { display: grid; grid-template-columns: 1fr 1fr; gap: 16px 28px; margin-top: 16px; }
.mm-check { display: block; width: 100%; max-width: 760px; height: auto; margin: 18px 0 0; }
.rl-rows { display: grid; gap: 8px; margin-top: 22px; }
.rl-row { display: grid; grid-template-columns: minmax(0, 1.6fr) repeat(3, minmax(0, 1fr)); gap: 8px 16px; align-items: center; padding: 12px 14px; border-radius: 14px; background: var(--paper-2); transition: opacity .2s; }
.rl-row.best { box-shadow: inset 0 0 0 2px var(--savings); }
.rl-row.miss { opacity: .45; }
.rl-name b { display: block; }
.rl-name small, .rl-cell small { color: var(--ink-2); font-size: 12.5px; }
.rl-cell small { display: block; font-size: 11.5px; font-weight: 700; letter-spacing: .05em; text-transform: uppercase; color: var(--ink-3); }
.rl-cell b { font-variant-numeric: tabular-nums; }
.mm-rules { list-style: none; padding: 0; margin: 16px 0 0; display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 12px; }
.mm-rules li { display: flex; gap: 14px; align-items: flex-start; background: var(--card); border-radius: 18px; padding: 14px 16px; box-shadow: 0 1px 0 var(--line); }
.mm-n { flex: none; width: 34px; height: 34px; border-radius: 50%; display: grid; place-items: center; background: var(--accent); color: var(--on-color); font-weight: 700; }
.mm-rules b { font-size: 16px; }
.mm-rules p { margin: 3px 0 0; color: var(--ink-2); font-size: 14.5px; line-height: 1.45; }
.rr-scene { margin: 20px 0 16px; font-size: 19px; line-height: 1.55; max-width: 720px; animation: fd-in .4s var(--ease); }
.rr-opts { max-width: 720px; }
#rr .fd-why, #rr .fd-next { max-width: 720px; }
@media (max-width: 760px) {
  .rl-row { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .rl-name { grid-column: 1 / -1; }
  .fd-top { flex-direction: column; }
  .pg-score { text-align: left; }
}
@media (max-width: 560px) {
  .mm-two { grid-template-columns: 1fr; }
  .rr-scene { font-size: 17px; }
}
@media (prefers-reduced-motion: reduce) {
  .mm-bill, .mm-bee, .rr-scene { animation: none; }
}
@keyframes fd-in { from { opacity: 0; transform: translateY(8px); } }