:root {
    --verb-ink: #20243b;
    --verb-muted: #5e6478;
    --verb-red: #b71c1c;
    --verb-blue: #0d47a1;
    --verb-sky: #0277bd;
    --verb-green: #2e7d32;
    --verb-gold: #ef8c18;
    --verb-paper: #ffffff;
    --verb-bg: #f4f7f6;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
    margin: 0;
    color: var(--verb-ink);
    background:
        radial-gradient(circle at 8% 3%, rgba(2, 119, 189, .10), transparent 24rem),
        radial-gradient(circle at 92% 18%, rgba(183, 28, 28, .08), transparent 22rem),
        var(--verb-bg);
    font-family: Arial, Helvetica, sans-serif;
}

.verb-page {
    width: min(1180px, calc(100% - 32px));
    margin: 0 auto;
    padding: 24px 0 64px;
}

.verb-series {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
    margin-bottom: 26px;
    padding: 8px;
    border: 1px solid #dfe3ec;
    border-radius: 16px;
    background: rgba(255, 255, 255, .82);
    box-shadow: 0 8px 24px rgba(32, 36, 59, .06);
}

.verb-series a {
    padding: 11px 10px;
    border-radius: 11px;
    color: #5a6073;
    font-size: 14px;
    font-weight: 700;
    text-align: center;
    text-decoration: none;
}

.verb-series a:hover { background: #eef4fb; color: var(--verb-blue); }

.verb-series a.is-current {
    color: #fff;
    background: linear-gradient(135deg, var(--verb-blue), var(--verb-sky));
    box-shadow: 0 5px 14px rgba(13, 71, 161, .24);
}

.verb-heading {
    max-width: 850px;
    margin: 0 auto 28px;
    text-align: center;
}

.verb-kicker,
.verb-section-heading > span,
.verb-ai-section > div > span {
    display: inline-block;
    margin-bottom: 8px;
    color: var(--verb-red);
    font-size: 12px;
    font-weight: 800;
    letter-spacing: .13em;
    text-transform: uppercase;
}

.verb-heading h1 {
    margin: 0;
    color: var(--verb-red);
    font-size: clamp(30px, 5vw, 48px);
    line-height: 1.08;
}

.verb-heading p {
    margin: 14px auto 0;
    color: var(--verb-muted);
    font-size: 18px;
    line-height: 1.55;
}

.verb-concept-map {
    position: relative;
    padding: clamp(22px, 4vw, 40px);
    overflow: hidden;
    border: 1px solid #e0e4ec;
    border-radius: 26px;
    background: var(--verb-paper);
    box-shadow: 0 14px 42px rgba(32, 36, 59, .10);
}

.verb-concept-map::before,
.verb-concept-map::after {
    position: absolute;
    width: 240px;
    height: 240px;
    border-radius: 50%;
    content: "";
    filter: blur(2px);
    pointer-events: none;
}

.verb-concept-map::before { top: -150px; left: -100px; background: rgba(2, 119, 189, .08); }
.verb-concept-map::after { right: -120px; bottom: -170px; background: rgba(183, 28, 28, .07); }

.verb-central-node {
    position: relative;
    z-index: 2;
    width: min(620px, 100%);
    margin: 0 auto;
    padding: 24px 28px;
    border: 3px solid var(--verb-red);
    border-radius: 20px;
    background: #fff;
    text-align: center;
    box-shadow: 0 10px 26px rgba(183, 28, 28, .13);
}

.verb-central-node span {
    color: var(--verb-blue);
    font-size: 12px;
    font-weight: 800;
    letter-spacing: .12em;
    text-transform: uppercase;
}

.verb-central-node h2 {
    margin: 6px 0 8px;
    color: var(--verb-red);
    font-size: clamp(24px, 4vw, 34px);
}

.verb-central-node p { margin: 0; font-size: 16px; line-height: 1.5; }

.verb-branches {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 20px;
    padding-top: 72px;
}

.verb-branches-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.verb-branches-4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }

.verb-branches::before {
    position: absolute;
    top: 34px;
    left: 16.66%;
    right: 16.66%;
    height: 3px;
    border-radius: 3px;
    background: var(--verb-sky);
    content: "";
}

.verb-branches-2::before { left: 25%; right: 25%; }
.verb-branches-4::before { left: 25%; right: 25%; }

.verb-branches::after {
    position: absolute;
    top: 0;
    left: 50%;
    width: 3px;
    height: 36px;
    background: var(--verb-sky);
    content: "";
}

.verb-branch {
    position: relative;
    min-width: 0;
    padding: 24px 18px 18px;
    border: 2px solid var(--branch-color, var(--verb-blue));
    border-radius: 18px;
    background: #fff;
    box-shadow: 0 8px 22px rgba(32, 36, 59, .08);
}

.verb-branch::before {
    position: absolute;
    top: -38px;
    left: 50%;
    width: 3px;
    height: 35px;
    background: var(--verb-sky);
    content: "";
}

.verb-branch::after {
    position: absolute;
    top: -6px;
    left: calc(50% - 5px);
    width: 0;
    height: 0;
    border-top: 9px solid var(--verb-sky);
    border-right: 5px solid transparent;
    border-left: 5px solid transparent;
    content: "";
}

.verb-tone-blue { --branch-color: #0d47a1; --branch-soft: #eef4ff; }
.verb-tone-red { --branch-color: #b71c1c; --branch-soft: #fff0f0; }
.verb-tone-green { --branch-color: #2e7d32; --branch-soft: #eff8f0; }
.verb-tone-gold { --branch-color: #c26900; --branch-soft: #fff6e7; }

.verb-branch-number {
    position: absolute;
    top: -17px;
    left: 18px;
    display: grid;
    width: 34px;
    height: 34px;
    place-items: center;
    border-radius: 50%;
    color: #fff;
    background: var(--branch-color);
    font-weight: 800;
    box-shadow: 0 4px 10px rgba(32, 36, 59, .18);
}

.verb-branch h3 {
    margin: 0 0 8px;
    color: var(--branch-color);
    font-size: 21px;
    text-align: center;
}

.verb-branch-lead {
    min-height: 42px;
    margin: 0 0 14px;
    color: var(--verb-muted);
    font-size: 14px;
    line-height: 1.45;
    text-align: center;
}

.verb-nodes { display: grid; gap: 10px; }

.verb-node {
    padding: 13px;
    border-radius: 12px;
    background: var(--branch-soft);
}

.verb-node h4 { margin: 0 0 5px; color: var(--branch-color); font-size: 15px; }
.verb-node > p { margin: 0; font-size: 14px; line-height: 1.45; }

.verb-node .verb-example {
    margin-top: 8px;
    padding-top: 8px;
    border-top: 1px dashed #b9c5d3;
    color: #35394b;
    font-style: italic;
}

.verb-node .verb-example strong { color: var(--branch-color); font-style: normal; }

.verb-notice {
    position: relative;
    z-index: 2;
    display: flex;
    gap: 12px;
    align-items: center;
    margin: 24px auto 0;
    padding: 15px 18px;
    border-left: 5px solid var(--verb-gold);
    border-radius: 12px;
    background: #fff7df;
    line-height: 1.45;
}

.verb-notice strong { color: #9a4d00; white-space: nowrap; }

.verb-map-cta {
    position: relative;
    z-index: 2;
    display: block;
    width: max-content;
    max-width: 100%;
    margin: 26px auto 0;
    padding: 13px 22px;
    border-radius: 999px;
    color: #fff;
    background: var(--verb-red);
    font-weight: 800;
    text-decoration: none;
    box-shadow: 0 6px 16px rgba(183, 28, 28, .22);
}

.verb-flashcards-section {
    width: min(760px, 100%);
    margin: 60px auto 0;
    scroll-margin-top: 90px;
}

.verb-section-heading { margin-bottom: 24px; text-align: center; }
.verb-section-heading h2 { margin: 0; color: var(--verb-red); font-size: 32px; }
.verb-section-heading p { margin: 8px 0 0; color: var(--verb-muted); line-height: 1.5; }

.verb-progress { margin-bottom: 12px; }
.verb-progress-copy { display: flex; justify-content: space-between; margin-bottom: 7px; color: #555d73; font-size: 13px; font-weight: 700; }
.verb-progress-track { height: 8px; overflow: hidden; border-radius: 999px; background: #dfe5ec; }
.verb-progress-track span { display: block; width: 0; height: 100%; border-radius: inherit; background: linear-gradient(90deg, var(--verb-sky), var(--verb-green)); transition: width .35s ease; }

.verb-card-area { perspective: 1200px; }

.verb-flashcard {
    width: 100%;
    min-height: 350px;
    cursor: pointer;
    outline: none;
}

.verb-flashcard:focus-visible .verb-flashcard-inner { box-shadow: 0 0 0 4px rgba(2, 119, 189, .25), 0 15px 34px rgba(32, 36, 59, .16); }

.verb-flashcard-inner {
    position: relative;
    width: 100%;
    min-height: 350px;
    transition: transform .55s ease;
    transform-style: preserve-3d;
    box-shadow: 0 15px 34px rgba(32, 36, 59, .16);
    border-radius: 22px;
}

.verb-flashcard.is-flipped .verb-flashcard-inner { transform: rotateY(180deg); }

.verb-card-face {
    position: absolute;
    inset: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 34px;
    border-radius: 22px;
    backface-visibility: hidden;
    text-align: center;
}

.verb-card-front { color: #fff; background: linear-gradient(145deg, var(--verb-blue), var(--verb-sky)); }
.verb-card-back { border: 4px solid var(--verb-red); color: var(--verb-ink); background: #fff; transform: rotateY(180deg); }
.verb-card-tag { margin-bottom: 18px; padding: 6px 10px; border-radius: 999px; background: rgba(255, 255, 255, .16); font-size: 11px; font-weight: 800; letter-spacing: .1em; text-transform: uppercase; }
.verb-card-back .verb-card-tag { color: var(--verb-red); background: #ffeded; }
.verb-card-face p { max-width: 620px; margin: 0; font-size: clamp(20px, 3.6vw, 27px); font-weight: 700; line-height: 1.42; }
.verb-card-front small { margin-top: 28px; opacity: .82; }

.verb-card-actions { display: flex; gap: 10px; justify-content: center; margin-top: 28px; }

.verb-btn {
    padding: 11px 17px;
    border: 0;
    border-radius: 10px;
    color: #fff;
    font: 800 14px Arial, sans-serif;
    cursor: pointer;
}

.verb-btn:hover { filter: brightness(.94); }
.verb-btn-review { background: #c62828; }
.verb-btn-correct { background: var(--verb-green); }
.verb-btn-restart { background: var(--verb-blue); }

.verb-complete {
    padding: 36px 24px;
    border: 2px solid #9fcda2;
    border-radius: 20px;
    background: #eff8f0;
    text-align: center;
}

.verb-complete > span { display: grid; width: 54px; height: 54px; margin: 0 auto 12px; place-items: center; border-radius: 50%; color: #fff; background: var(--verb-green); font-size: 27px; }
.verb-complete h3 { margin: 0; color: var(--verb-green); font-size: 27px; }
.verb-complete p { margin: 8px 0 20px; color: var(--verb-muted); }

.verb-ai-section {
    display: flex;
    gap: 24px;
    align-items: center;
    justify-content: space-between;
    margin-top: 54px;
    padding: 28px 32px;
    border-radius: 22px;
    color: #fff;
    background: linear-gradient(135deg, #24264a, #15162d);
    box-shadow: 0 14px 34px rgba(21, 22, 45, .18);
}

.verb-ai-section > div > span { color: #8f84ff; }
.verb-ai-section h2 { margin: 0 0 7px; font-size: 26px; }
.verb-ai-section p { max-width: 680px; margin: 0; color: #d7d8e7; line-height: 1.5; }
.verb-ai-section .final-link { flex: 0 0 auto; padding: 13px 20px; border-radius: 999px; color: #fff; background: #6556e8; font-weight: 800; text-decoration: none; box-shadow: 0 7px 18px rgba(101, 86, 232, .3); }

@media (max-width: 900px) {
    .verb-branches,
    .verb-branches-2,
    .verb-branches-4 { grid-template-columns: 1fr; gap: 16px; padding-top: 44px; }
    .verb-branches::before { display: none; }
    .verb-branches::after { height: 35px; }
    .verb-branch::before,
    .verb-branch::after { display: none; }
    .verb-branch { padding-top: 22px; }
    .verb-branch-lead { min-height: 0; }
}

@media (max-width: 680px) {
    .verb-page { width: min(100% - 20px, 1180px); padding-top: 14px; }
    .verb-series { grid-template-columns: repeat(2, 1fr); }
    .verb-series a { font-size: 12px; }
    .verb-heading p { font-size: 16px; }
    .verb-concept-map { padding: 20px 14px; border-radius: 19px; }
    .verb-central-node { padding: 20px 16px; }
    .verb-notice { align-items: flex-start; flex-direction: column; gap: 5px; }
    .verb-card-face { padding: 25px 18px; }
    .verb-flashcard,
    .verb-flashcard-inner { min-height: 390px; }
    .verb-card-actions { width: 100%; flex-direction: column; }
    .verb-card-actions .verb-btn { width: 100%; }
    .verb-ai-section { align-items: flex-start; flex-direction: column; padding: 24px 20px; }
    .verb-ai-section .final-link { width: 100%; text-align: center; }
}