/* ===== 凑十法分解练习 ===== */
#mtApp .mt-hero { text-align: center; padding: 12px 10px 0; }
#mtApp .mt-hero h1 { font-size: 30px; font-weight: 800; color: var(--c-text); margin-bottom: 10px; }
#mtApp .mt-hero p { font-size: 15px; color: var(--c-text-sub); line-height: 1.7; }

#mtApp .mt-bar { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; margin: 18px 0; }
#mtApp .mt-tab {
    border: 2px solid var(--c-primary); background: transparent; color: var(--c-primary);
    border-radius: 999px; padding: 8px 16px; font-size: 14px; font-weight: 700;
    cursor: pointer; transition: background .15s, color .15s;
}
#mtApp .mt-tab.is-on { background: var(--c-primary); color: #fff; }

#mtApp .mt-panel {
    max-width: 720px; margin: 0 auto; background: var(--c-surface);
    border: 1px solid var(--c-border); border-radius: var(--radius-md);
    padding: 20px 16px; box-shadow: var(--shadow-md); text-align: center;
}

#mtApp .mt-expr { font-size: 38px; font-weight: 800; color: var(--c-text); letter-spacing: 2px; }
#mtApp .mt-expr .hi { color: var(--c-primary); }

#mtApp .mt-fig { margin: 14px auto 4px; max-width: 440px; }
#mtApp .mt-fig svg { width: 100%; height: auto; display: block; }
#mtApp .mt-moved { animation: mtPop .45s ease; transform-origin: center; }
@keyframes mtPop { 0% { transform: scale(.4); opacity: 0; } 70% { transform: scale(1.18); } 100% { transform: scale(1); opacity: 1; } }

#mtApp .mt-tip {
    display: inline-block; margin-top: 8px; padding: 8px 16px; border-radius: 999px;
    background: var(--c-primary-soft); border: 1px solid var(--c-border);
    font-size: 14px; font-weight: 700; color: var(--c-primary);
}

#mtApp .mt-q { margin-top: 18px; font-size: 18px; font-weight: 800; color: var(--c-text); line-height: 1.8; }
#mtApp .mt-q b { color: var(--c-primary); font-size: 22px; }

#mtApp .mt-opts { display: flex; flex-wrap: wrap; gap: 10px; justify-content: center; margin-top: 14px; }
#mtApp .mt-opt {
    border: 2px solid var(--c-border); background: var(--c-surface-soft); color: var(--c-text);
    border-radius: 14px; padding: 13px 18px; font-size: 19px; font-weight: 800; cursor: pointer; transition: .15s;
}
#mtApp .mt-opt:hover { border-color: var(--c-primary); color: var(--c-primary); }
#mtApp .mt-opt.ok { border-color: var(--c-accent-green); background: var(--c-primary-soft); color: var(--c-primary); }
#mtApp .mt-opt.bad { border-color: #e03131; color: #e03131; }

#mtApp .mt-fill { margin-top: 14px; display: none; }
#mtApp .mt-fill.show { display: block; }
#mtApp .mt-in {
    width: 110px; height: 62px; border: 2px solid var(--c-primary); border-radius: 14px;
    background: var(--c-surface-soft); color: var(--c-primary);
    font-size: 28px; font-weight: 800; text-align: center; outline: none;
}
#mtApp .mt-in.ok { border-color: var(--c-accent-green); background: var(--c-primary-soft); }
#mtApp .mt-in.bad { border-color: #e03131; background: #fff0f0; color: #e03131; }

#mtApp .mt-steps {
    margin-top: 16px; display: flex; flex-wrap: wrap; gap: 10px; justify-content: center;
    font-size: 15px; font-weight: 700; color: var(--c-text-sub);
}
#mtApp .mt-steps span { padding: 6px 14px; border-radius: 999px; background: var(--c-surface-soft); border: 1px solid var(--c-border); }
#mtApp .mt-steps span.done { background: var(--c-primary-soft); color: var(--c-primary); border-color: var(--c-primary); }

#mtApp .mt-msg { font-size: 17px; font-weight: 800; min-height: 26px; margin-top: 14px; color: var(--c-text); }
#mtApp .mt-msg.ok { color: var(--c-primary); }
#mtApp .mt-msg.bad { color: #e03131; }

#mtApp .mt-ctrl { display: flex; flex-wrap: wrap; gap: 10px; justify-content: center; margin-top: 18px; }
#mtApp .mt-btn {
    border: none; border-radius: 999px; padding: 12px 20px; font-size: 15px; font-weight: 700;
    color: #fff; cursor: pointer; background: linear-gradient(135deg, var(--c-primary), var(--c-accent-cyan));
    box-shadow: var(--shadow-md);
}
#mtApp .mt-btn.gray { background: var(--c-surface-2); color: var(--c-text); box-shadow: none; border: 1px solid var(--c-border); }
#mtApp .mt-btn:disabled { opacity: .5; cursor: default; }

#mtApp .mt-stat {
    max-width: 720px; margin: 18px auto 0; background: var(--c-surface);
    border: 1px solid var(--c-border); border-radius: var(--radius-md);
    padding: 14px 18px; box-shadow: var(--shadow-md); text-align: center;
    font-size: 14px; line-height: 1.9; color: var(--c-text-sub);
}
#mtApp .mt-stat b { color: var(--c-primary); font-size: 18px; }

#mtApp .mt-ai, #mtApp .mt-info { max-width: 720px; margin: 30px auto 0; }
#mtApp .mt-ai h2, #mtApp .mt-info h2 { font-size: 20px; font-weight: 800; color: var(--c-text); margin-bottom: 10px; }
#mtApp .mt-ai p { font-size: 14px; color: var(--c-text-sub); line-height: 1.8; margin-bottom: 14px; }
#mtApp .mt-ai-row { display: flex; gap: 10px; flex-wrap: wrap; }
#mtApp .mt-out {
    margin-top: 14px; background: var(--c-surface-soft); border: 1px solid var(--c-border);
    border-radius: var(--radius-sm); padding: 16px 18px;
    font-size: 15px; line-height: 1.85; color: var(--c-text); white-space: pre-wrap;
}
#mtApp .mt-info ul { list-style: disc; padding-left: 22px; margin-bottom: 24px; }
#mtApp .mt-info li { font-size: 14px; line-height: 1.9; color: var(--c-text-sub); margin-bottom: 8px; }
#mtApp .mt-info li b { color: var(--c-text); }

@media (max-width: 560px) {
    #mtApp .mt-hero h1 { font-size: 24px; }
    #mtApp .mt-expr { font-size: 30px; }
}