.fretboard-interval-lesson { min-height: 40vh; background: linear-gradient(rgba(0,0,0,.78), rgba(0,0,0,.78)), url('../images/backgrounds/blackhex.webp') center top / 100% auto repeat-y; }
.fretboard-interval-lesson::before { display: none; }
.lesson-content-wrap.fretboard-lesson-footer { min-height: 0; padding-top: 0; padding-bottom: 0; }
.lesson-hero-media .fretboard-hero-guitar { position: absolute; inset: 0 0 0 auto; width: min(75%, 1200px); height: 100%; object-fit: contain; object-position: right center; opacity: .65; pointer-events: none; }
.lesson-hero-media .lesson-hero-overlay { z-index: 1; }
.lesson-hero-media .fretboard-hero-staff { left: -3%; right: auto; z-index: 3; opacity: .10; filter: brightness(0) saturate(100%) invert(78%) sepia(32%) saturate(640%) hue-rotate(3deg) brightness(104%) blur(4px); }
.fretboard-interval-lesson .lesson-section a:not(.theory-hero__button) { color: #efc65f; text-decoration: underline; }
.fretboard-interval-lesson .lesson-section a:not(.theory-hero__button):hover,
.fretboard-interval-lesson .lesson-section a:not(.theory-hero__button):focus-visible { color: #fff0b8; }
.lesson-section > .interval-letter-diagram { width: min(100%, 620px); margin: 2rem 0; padding: 1.5rem; border-top: 1px solid #d6a441; border-bottom: 1px solid #d6a441; text-align: center; }
.interval-letter-diagram__notes { display: flex; align-items: center; justify-content: space-between; gap: .35rem; color: #efc65f; }
.interval-letter-diagram__notes span { font-size: clamp(1.5rem, 4vw, 2.2rem); font-weight: 700; }
.interval-letter-diagram__notes i { color: #c9b88f; font-size: 1.2rem; font-style: normal; }
.interval-letter-diagram figcaption { margin-top: .8rem; color: #e6ded0; font-size: .85rem; }

.moving-fifth-section { background: #292723; padding: clamp(2.5rem, 5vw, 5rem) 0; }
.moving-fifth-section > .moving-fifth { width: min(90vw, 1500px); max-width: none; margin: 0 auto; padding: 0; }
.moving-fifth-section .moving-fifth__heading { color: #f3cd70; }
.moving-fifth-section .moving-fifth figcaption { color: #fff; }
.moving-fifth__heading { display: grid; place-items: center; margin-bottom: 1rem; color: #efc65f; font-size: 1.6rem; font-weight: 700; }
.moving-fifth__heading span { grid-area: 1 / 1; }
.moving-fifth__board { overflow-x: auto; }
.moving-fifth__svg { display: block; width: 100%; min-width: 560px; height: auto; }
.moving-fifth__svg circle { stroke: #111; stroke-width: 3; }
.moving-fifth__svg text { fill: #14100a; font: bold 30px sans-serif; text-anchor: middle; dominant-baseline: central; }
.moving-fifth__root circle { fill: #e0ad3f; }
.moving-fifth__fifth circle { fill: #f5e7bc; }
.moving-fifth__root { animation: fifth-root 9s ease-in-out infinite; }
.moving-fifth__fifth { animation: fifth-note 9s ease-in-out infinite; }
.moving-fifth figcaption { margin-top: 1rem; color: #d9d4c9; font-size: .85rem; text-align: center; }
@keyframes fifth-root {
  0%, 27% { transform: translateX(-500px); }
  33.333%, 60.333% { transform: translateX(0); }
  66.666%, 93.666% { transform: translateX(500px); }
  100% { transform: translateX(-500px); }
}
@keyframes fifth-note {
  0%, 27% { transform: translateX(-500px); }
  33.333%, 60.333% { transform: translateX(0); }
  66.666%, 93.666% { transform: translateX(500px); }
  100% { transform: translateX(-500px); }
}
.moving-fifth__label { opacity: 0; animation-duration: 9s; animation-iteration-count: infinite; animation-timing-function: steps(1, end); }
.moving-fifth__label--g { animation-name: fifth-label-g; }
.moving-fifth__label--a { animation-name: fifth-label-a; }
.moving-fifth__label--b { animation-name: fifth-label-b; }
@keyframes fifth-label-g { 0% { opacity: 1; } 33.333% { opacity: 0; } 100% { opacity: 1; } }
@keyframes fifth-label-a { 0% { opacity: 0; } 33.333% { opacity: 1; } 66.666% { opacity: 0; } }
@keyframes fifth-label-b { 0% { opacity: 0; } 66.666% { opacity: 1; } 100% { opacity: 0; } }
@media (prefers-reduced-motion: reduce) { .moving-fifth__root, .moving-fifth__fifth, .moving-fifth__label { animation: none; } .moving-fifth__root, .moving-fifth__fifth { transform: translateX(-500px); } .moving-fifth__label--g { opacity: 1; } }

.lesson-section > .power-chord-diagram { width: min(90vw, 1500px); max-width: none; margin: 2.5rem 0 2.5rem calc(50% - min(45vw, 750px)); padding: 0; }
.moving-fifth__octave { animation: fifth-note 9s ease-in-out infinite; }
.moving-fifth__octave circle { fill: #e0ad3f; }
@media (prefers-reduced-motion: reduce) { .moving-fifth__octave { animation: none; transform: translateX(-500px); } }

.power-chord-diagram .moving-fifth__svg text { font-size: 24px; }

.lesson-section > .tuning-fifth-diagram { width: min(90vw, 1500px); max-width: none; margin: 2.5rem 0 2.5rem calc(50% - min(45vw, 750px)); padding: 0; }
.tuning-fifth-diagram .moving-fifth__root { animation: tuning-root 15s ease-in-out infinite; }
.tuning-fifth-diagram .moving-fifth__fifth { animation: tuning-fifth 15s ease-in-out infinite; }
@keyframes tuning-root {
  0%, 16% { transform: translate(-500px, 0); }
  20%, 36% { transform: translate(-500px, -50px); }
  40%, 56% { transform: translate(-500px, -100px); }
  60%, 76% { transform: translate(-500px, -150px); }
  80%, 96% { transform: translate(-500px, -200px); }
  100% { transform: translate(-500px, 0); }
}
@keyframes tuning-fifth {
  0%, 16% { transform: translate(-500px, 0); }
  20%, 36% { transform: translate(-500px, -50px); }
  40%, 56% { transform: translate(-500px, -100px); }
  60%, 76% { transform: translate(-250px, -150px); }
  80%, 96% { transform: translate(-500px, -200px); }
  100% { transform: translate(-500px, 0); }
}
.tuning-label { opacity: 0; animation-duration: 15s; animation-iteration-count: infinite; animation-timing-function: steps(1, end); }
.tuning-label--g { animation-name: tuning-label-g; }
@keyframes tuning-label-g { 0% { opacity: 1; } 20% { opacity: 0; } 100% { opacity: 1; } }
.tuning-label--c { animation-name: tuning-label-c; }
@keyframes tuning-label-c { 0% { opacity: 0; } 20% { opacity: 1; } 40% { opacity: 0; } }
.tuning-label--f { animation-name: tuning-label-f; }
@keyframes tuning-label-f { 0% { opacity: 0; } 40% { opacity: 1; } 60% { opacity: 0; } }
.tuning-label--bb { animation-name: tuning-label-bb; }
@keyframes tuning-label-bb { 0% { opacity: 0; } 60% { opacity: 1; } 80% { opacity: 0; } }
.tuning-label--d { animation-name: tuning-label-d; }
@keyframes tuning-label-d { 0% { opacity: 0; } 80% { opacity: 1; } 100% { opacity: 0; } }
@media (prefers-reduced-motion: reduce) { .tuning-fifth-diagram .moving-fifth__root, .tuning-fifth-diagram .moving-fifth__fifth, .tuning-label { animation: none; } .tuning-fifth-diagram .moving-fifth__root, .tuning-fifth-diagram .moving-fifth__fifth { transform: translate(-500px, 0); } .tuning-label--g { opacity: 1; } }

.minor-third-diagram .moving-fifth__root, .minor-third-diagram .moving-fifth__fifth { animation: minor-shape 9s ease-in-out infinite; }
@keyframes minor-shape { 0%, 27% { transform: translateX(0); } 33.333%, 60.333% { transform: translateX(500px); } 66.666%, 93.666% { transform: translateX(750px); } 100% { transform: translateX(0); } }
.minor-third-diagram .moving-fifth__fifth circle { fill: #83daa9; }
.minor-label { opacity: 0; animation-duration: 9s; animation-iteration-count: infinite; animation-timing-function: steps(1, end); }
.minor-label--a { animation-name: fifth-label-g; }
.minor-label--b { animation-name: fifth-label-a; }
.minor-label--c { animation-name: fifth-label-b; }
@media (prefers-reduced-motion: reduce) { .minor-third-diagram .moving-fifth__root, .minor-third-diagram .moving-fifth__fifth, .minor-label { animation: none; } .minor-third-diagram .moving-fifth__root, .minor-third-diagram .moving-fifth__fifth { transform: none; } .minor-label--a { opacity: 1; } }

.minor-strings-diagram .moving-fifth__root { animation: minor-strings-root 15s ease-in-out infinite; }
.minor-strings-diagram .moving-fifth__fifth { animation: minor-strings-third 15s ease-in-out infinite; }
@keyframes minor-strings-root {
  0%, 16% { transform: translate(0, 0); }
  20%, 36% { transform: translate(0, -50px); }
  40%, 56% { transform: translate(0, -100px); }
  60%, 76% { transform: translate(0, -150px); }
  80%, 96% { transform: translate(0, -200px); }
  100% { transform: translate(0, 0); }
}
@keyframes minor-strings-third {
  0%, 16% { transform: translate(0, 0); }
  20%, 36% { transform: translate(0, -50px); }
  40%, 56% { transform: translate(0, -100px); }
  60%, 76% { transform: translate(250px, -150px); }
  80%, 96% { transform: translate(0, -200px); }
  100% { transform: translate(0, 0); }
}
.minor-strings-label { opacity: 0; animation-duration: 15s; animation-iteration-count: infinite; animation-timing-function: steps(1, end); }
.minor-strings-label--ab { animation-name: tuning-label-g; }
.minor-strings-label--d { animation-name: tuning-label-c; }
.minor-strings-label--g { animation-name: tuning-label-f; }
.minor-strings-label--c { animation-name: tuning-label-bb; }
.minor-strings-label--e { animation-name: tuning-label-d; }
@media (prefers-reduced-motion: reduce) { .minor-strings-diagram .moving-fifth__root, .minor-strings-diagram .moving-fifth__fifth, .minor-strings-label { animation: none; } .minor-strings-diagram .moving-fifth__root, .minor-strings-diagram .moving-fifth__fifth { transform: translate(0, 0); } .minor-strings-label--ab { opacity: 1; } }

.major-third-diagram .moving-fifth__root, .major-third-diagram .moving-fifth__fifth { animation: minor-shape 9s ease-in-out infinite; }
.major-third-diagram .moving-fifth__fifth circle { fill: #83daa9; }
@media (prefers-reduced-motion: reduce) { .major-third-diagram .moving-fifth__root, .major-third-diagram .moving-fifth__fifth { animation: none; transform: none; } }

.major-strings-diagram .moving-fifth__root { animation: tuning-root 15s ease-in-out infinite; }
.major-strings-diagram .moving-fifth__fifth { animation: major-strings-third 15s ease-in-out infinite; }
@keyframes major-strings-third {
  0%, 16% { transform: translate(0, 0); }
  20%, 36% { transform: translate(0, -50px); }
  40%, 56% { transform: translate(0, -100px); }
  60%, 76% { transform: translate(250px, -150px); }
  80%, 96% { transform: translate(0, -200px); }
  100% { transform: translate(0, 0); }
}
@keyframes major-strings-root {
  0%, 16% { transform: translate(0, 0); }
  20%, 36% { transform: translate(0, -50px); }
  40%, 56% { transform: translate(0, -100px); }
  60%, 76% { transform: translate(0, -150px); }
  80%, 96% { transform: translate(0, -200px); }
  100% { transform: translate(0, 0); }
}
.major-strings-diagram .moving-fifth__root { animation-name: major-strings-root; }
@media (prefers-reduced-motion: reduce) { .major-strings-diagram .moving-fifth__root, .major-strings-diagram .moving-fifth__fifth { animation: none; transform: none; } }

.moving-fifth .fretboard-diagram-title { margin: 0 0 1.4rem; color: #f5f1e8; text-align: center; font-size: clamp(1.2rem, 2vw, 1.7rem); }

.major-third-diagram .moving-fifth__svg text { font-size: 24px; }
.interval-test__button { background: #d6a441; color: #17120a; border: 0; border-radius: 4px; padding: .8rem 1.2rem; font: inherit; font-weight: 700; cursor: pointer; }
.interval-test > #interval-test-start { margin-top: 1.5rem; }
.interval-test__button:focus-visible { outline: 3px solid #fff; outline-offset: 3px; }
.lesson-section .interval-test__progress { color: #efc65f; margin-top: 2rem; }
.interval-test__scroll { overflow-x: auto; margin: 1.5rem 0; }
.interval-test__svg { display: block; width: 100%; min-width: 700px; height: auto; }
.interval-test__target-line { stroke: #f0ca6a; stroke-width: 22; stroke-opacity: .35; }
.interval-test__root circle { fill: #e0ad3f; stroke: #111; stroke-width: 3; }
.interval-test__root text { fill: #111; font: bold 30px sans-serif; }
.interval-test__fret-number { fill: #efc65f; font: 26px sans-serif; }
.interval-test__fret { fill: transparent; cursor: pointer; }
.interval-test__fret:hover, .interval-test__fret:focus { fill: rgba(255, 226, 148, .35); outline: none; stroke: #fff0b8; stroke-width: 5; }
.interval-test__fret[aria-disabled="true"] { cursor: default; }
.interval-test__picked.is-correct { fill: #78dca3; stroke: #111; stroke-width: 3; }
.interval-test__picked.is-wrong { fill: #ef8075; stroke: #111; stroke-width: 3; }
.lesson-section .interval-test__hint { font-size: .85rem; color: #d4cdc0; }
.lesson-section .interval-test__feedback { min-height: 2em; font-weight: 700; }
.lesson-section .interval-test__feedback.is-correct { color: #9fe7b8; }
.lesson-section .interval-test__feedback.is-wrong { color: #ff9c91; }

.interval-test__scroll { width: min(90vw, 1500px); max-width: none; margin-left: calc(50% - min(45vw, 750px)); }
.interval-test .lesson-final-actions { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: .8rem; margin-top: 3rem; }
.interval-test .lesson-final-actions .theory-hero__button { display: inline-flex; width: 100%; min-height: 48px; align-items: center; justify-content: center; padding: .75rem 1.25rem; border: 1px solid #9f792e; border-radius: 8px; color: #f7f3ea; background: rgba(5, 5, 5, .74); font-size: .76rem; font-weight: 800; letter-spacing: .045em; text-decoration: none; text-transform: uppercase; }
.interval-test .lesson-final-actions .theory-hero__button--primary { color: #171109; border-color: #efd58c; background: #d6a441; }
.interval-test .lesson-final-actions .theory-hero__button:focus-visible { outline: 3px solid #fff; outline-offset: 3px; }
@media (max-width: 600px) { .interval-test .lesson-final-actions { grid-template-columns: 1fr; } }
.interval-test__question-card { margin-top: 2rem; padding: 1.25rem 1.5rem; border-left: 3px solid #d6a441; background: #171510; }
.interval-test__status { display: flex; flex-wrap: wrap; justify-content: space-between; gap: .5rem 1.5rem; margin-bottom: .75rem; }
.lesson-section .interval-test__status p { margin: 0; color: #efc65f; font-size: .95rem; }
.interval-test__question-card h3 { margin: 0 0 .55rem; }
.lesson-section .interval-test__question-card > p { margin: 0; }
.interval-test__question-card.is-entering { animation: interval-question-enter .65s cubic-bezier(.2,.8,.2,1) both; }
@keyframes interval-question-enter { from { opacity: 0; transform: translateX(-24px); } to { opacity: 1; transform: translateX(0); } }
@media (prefers-reduced-motion: reduce) { .interval-test__question-card.is-entering { animation: none; } }