:root { font-family: ui-rounded, "Trebuchet MS", system-ui, sans-serif; color: #143e35; background: #eff8f1; color-scheme: light; }
* { box-sizing: border-box; }
[hidden] { display: none !important; }
body { margin: 0; background: radial-gradient(ellipse at top right, #fff3c7, transparent 65%); min-height: 100vh; }
a { color: #126344; }
button, audio { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
button { cursor: pointer; }
button:disabled { cursor: default; }
:focus-visible { outline: 3px solid #327bd1; outline-offset: 4px; }
h1:focus { outline: none; }
.lesson-nav { max-width: 1080px; margin: auto; display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 12px; padding: 16px 24px; }
.lesson-brand { display: flex; align-items: center; gap: 7px; font-weight: 900; font-size: 20px; text-decoration: none; }
.lesson-brand span { color: #c4472a; }
.lesson-nav form { display: flex; gap: 6px; }
.lesson-nav button { min-height: 44px; border: 1px solid #cadfd2; background: #fff; border-radius: 12px; padding: 8px 12px; color: #143e35; }
.lesson-nav [aria-current] { background: #073f35; color: white; }
.lesson-shell { max-width: 700px; margin: 12px auto 32px; padding: 0 20px; }
.lesson-intro { text-align: center; }
.lesson-badge { display: inline-block; background: #d8f2dd; border-radius: 99px; padding: 8px 16px; font-size: 14px; font-weight: 700; }
.lesson-intro p { line-height: 1.6; }
progress { display: block; width: 100%; height: 12px; margin: 20px 0; border: 0; border-radius: 99px; overflow: hidden; background: #d0e5d6; accent-color: #168a4b; }
progress::-webkit-progress-bar { background: #d0e5d6; }
progress::-webkit-progress-value { background: #168a4b; border-radius: 99px; }
progress::-moz-progress-bar { background: #168a4b; }
.lesson-card { padding: clamp(20px, 4vw, 36px); border: 1px solid #d0e5d6; border-radius: 28px; background: white; box-shadow: 0 14px 45px #143e3510; text-align: center; }
.step-label { color: #527066; font-size: 14px; font-weight: 700; }
h1 { margin: 10px 0 18px; font-size: clamp(24px, 4vw, 32px); line-height: 1.2; }
p { line-height: 1.6; }
.lesson-picture { display: block; width: min(100%, 320px); height: 210px; object-fit: contain; margin: 0 auto 12px; border-radius: 20px; }
.phrase-picture { height: 160px; }
.lesson-word { font-size: 42px; }
.lesson-translation { margin-top: 4px; color: #527066; }
audio { display: block; width: min(100%, 320px); margin: 18px auto; }
.lesson-primary, .lesson-secondary { display: block; width: 100%; min-height: 54px; padding: 15px 20px; border: 0; border-radius: 16px; font-weight: 800; text-decoration: none; line-height: 1.4; }
.lesson-primary { background: #08733e; color: white; }
.lesson-primary:hover { background: #075c33; }
.lesson-secondary { margin-top: 12px; background: #eaf5ee; color: #143e35; }
.lesson-choices { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 12px; margin: 28px 0 14px; }
.lesson-choices button { min-height: 110px; min-width: 0; padding: 8px; border: 2px solid #c8ded0; border-radius: 18px; background: #f5faf6; color: #143e35; font-size: 22px; font-weight: 800; }
.lesson-choices button:hover:not(:disabled) { border-color: #08733e; background: #e6f5e9; }
.lesson-choices img { width: 100%; height: 100px; object-fit: contain; }
.choice-emoji { font-size: clamp(32px, 8vw, 54px); }
.lesson-choices .is-correct { border-color: #148445; background: #d9f3e1; }
.lesson-choices .is-retry { border-style: dashed; }
.lesson-choices :disabled:not(.is-correct) { opacity: .55; }
.lesson-feedback { min-height: 52px; font-weight: 700; }
.lesson-feedback.is-correct { color: #08733e; }
.lesson-phrase { font-size: 32px; }
.lesson-phrase strong { color: #08733e; }
.phrase-choices button { min-height: 70px; }
.phrase-choices span { display: block; }
.lesson-trophy { display: block; font-size: 70px; }
.lesson-summary { margin: 24px 0; padding: 20px; border-radius: 18px; background: #eff8f1; }
.lesson-summary strong { font-size: 24px; }
.lesson-footer { text-align: center; color: #527066; font-size: 14px; margin-top: 24px; }
.lesson-notice { padding: 16px; background: #fff3c7; border-radius: 12px; }
@media (max-width: 420px) { .lesson-nav { padding: 12px 16px; } .lesson-nav form { margin-left: auto; } .lesson-shell { padding: 0 12px; } .lesson-choices { gap: 8px; } .lesson-choices button { padding: 4px; font-size: 18px; } }