.time-setter,
.mode-selector,
.topic-selector {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    margin: 0 0 1.4rem 0;
    flex-wrap: wrap;
}

.subject-break {
    flex-basis: 100%;
    height: 0;
}

/* Group two subject buttons as a minimal segmented control */
.subject-btn-group {
    display: inline-flex;
    gap: 0;
    border: var(--pixel-border);
    border-radius: var(--radius-md);
    overflow: hidden;
}
.subject-btn-group .subject-btn {
    border-radius: 0;
    margin: 0;
}
.subject-btn-group .subject-btn + .subject-btn {
    border-left: 2px solid var(--primary);
}

/* 모드 버튼 세그먼트 스타일 - 평면 디자인 */
.mode-btn-group {
    display: inline-flex;
    gap: 0;
    border: var(--pixel-border);
    border-radius: var(--radius-sm);
    overflow: hidden;
    box-shadow: 0.2rem 0.2rem 0 var(--border-strong);
    background: var(--surface-muted);
    position: relative;
}

/* 슬라이딩 배경 제거 */
.mode-btn-group::before {
    display: none;
}

/* Hard 모드 선택 시 - 사용 안 함 */
.mode-btn-group[data-selected='hard-core']::before {
    display: none;
}

.mode-btn-group .mode-btn {
    border-radius: 0;
    margin: 0;
    border: none !important;
    box-shadow: none;
    background: transparent;
    color: var(--text-dark);
    min-width: 7.2rem;
    max-width: none;
    padding: 0.9rem 1rem;
    font-size: 1.2rem;
    line-height: 1;
    transition: none;
    position: relative;
    z-index: 1;
}

.mode-btn-group .mode-btn:hover {
    transform: none;
    box-shadow: none;
    background: var(--surface-elevated);
    color: var(--text-light);
}

.mode-btn-group .mode-btn:active {
    transform: translateY(2px); /* 클릭 시 아래로만 이동 */
    box-shadow: none;
}

.mode-btn-group .mode-btn + .mode-btn {
    border-left: 0.2rem solid var(--border-strong) !important;
}

.mode-btn-group .mode-btn.selected {
    color: var(--text-light) !important; /* 흰색 텍스트 */
    font-weight: 900;
    background: var(--primary-strong) !important;
    transform: none !important;
    box-shadow: none !important;
    border: none !important;
}

/* Group curriculum buttons (총론, 창체) with visual grouping */
.curriculum-group {
    display: inline-flex;
    gap: 0;
    border: var(--pixel-border);
    border-radius: var(--radius-md);
    overflow: hidden;
    background: var(--surface-muted);
    box-shadow: 0.3rem 0.3rem 0 var(--border-strong);
    position: relative;
}
.curriculum-group .subject-btn {
    border-radius: 0;
    margin: 0;
    border: none !important;
    box-shadow: none !important;
    position: relative;
}
.curriculum-group .subject-btn:hover {
    transform: none !important;
    box-shadow: none !important;
}
.curriculum-group .subject-btn + .subject-btn {
    border-left: 2px solid var(--primary) !important;
}
.curriculum-group .subject-btn:first-child {
    border-top-left-radius: 0;
    border-bottom-left-radius: 0;
}
.curriculum-group .subject-btn:last-child {
    border-top-right-radius: 0;
    border-bottom-right-radius: 0;
}

/* Arrange topic buttons in two rows with up to four per row */
.topic-selector {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(12rem, 1fr));
}
@media (min-width: 900px) {
    #start-modal .topic-selector {
        grid-template-columns: repeat(4, minmax(120px, 1fr));
    }
}
.topic-btn {
    width: 100%;
}
#time-setting-display {
    font-family: var(--font-mono);
    font-size: 3rem;
    color: var(--text-dark);
    width: 8ch;
    text-align: center;
    flex-shrink: 0;
}

.mode-time-grid #time-setting-display {
    font-size: 1.7rem;
    width: 5ch;
}
.time-control-btn {
    font-size: 1.6rem;
    padding: 0.7rem 0.9rem;
    min-width: 4.2rem;
    flex-shrink: 0;
    border-color: var(--border-strong) !important;
}

.mode-time-grid .time-control-btn {
    font-size: 1.6rem;
    padding: 0.7rem 0.9rem;
    min-width: 4.2rem;
}
.subject-btn,
.mode-btn,
.topic-btn,
#random-subject-btn {
    font-size: 1.45rem;
    min-height: 4.4rem;
}
.subject-btn,
.mode-btn,
.topic-btn,
#random-subject-btn,
#start-game-btn,
.time-control-btn {
    font-family: var(--font-display);
}
.subject-btn.selected,
.mode-btn.selected,
.topic-btn.selected {
    /* 점 패턴 제거 - 단순한 레드 배경 */
    background: var(--primary-strong) !important;
    color: var(--text-light) !important;
    font-weight: 900;
    transform: none;
    box-shadow: 0.25rem 0.25rem 0 var(--border-strong);
    border: 0.3rem solid var(--accent) !important;
    border-radius: var(--radius-sm);
}

/* 비선택된 버튼 스타일 강화 - 평면 디자인 */
.subject-btn:not(.selected),
.topic-btn:not(.selected) {
    background: var(--surface-muted) !important;
    border: var(--pixel-border) !important;
    color: var(--text-light) !important;
    border-radius: var(--radius-sm);
    box-shadow: 0.2rem 0.2rem 0 var(--border-strong);
}

.subject-btn:not(.selected):hover,
.topic-btn:not(.selected):hover {
    background: var(--surface-elevated) !important;
    border-color: var(--accent) !important;
    color: var(--text-light) !important;
    transform: translate(-0.1rem, -0.1rem);
    box-shadow: 0.3rem 0.3rem 0 var(--border-strong);
}

/* 하위 메뉴 버튼 비선택 상태 스타일 - .btn 기본 스타일 덮어쓰기 */
[id$='-submenu'] .btn.topic-sub-btn:not(.selected),
[id$='-submenu'] button.btn.topic-sub-btn:not(.selected),
[id$='-submenu'] .topic-sub-btn:not(.selected),
[id$='-submenu'] button.topic-sub-btn:not(.selected),
.btn.topic-sub-btn:not(.selected),
button.btn.topic-sub-btn:not(.selected),
.topic-sub-btn:not(.selected),
button.topic-sub-btn:not(.selected) {
    font-size: 1.2rem !important;
    padding: 0.5rem 0.6rem !important;
    transition: none !important;
    background: var(--surface-muted) !important;
    border: var(--pixel-border) !important;
    border-color: var(--border-strong) !important;
    color: var(--text-dark) !important;
    box-shadow: 0.2rem 0.2rem 0 var(--border-strong) !important;
    font-weight: normal !important;
    white-space: nowrap !important;
    border-radius: var(--radius-sm) !important;
    cursor: pointer !important;
}

[id$='-submenu'] .btn.topic-sub-btn:not(.selected):hover,
[id$='-submenu'] button.btn.topic-sub-btn:not(.selected):hover,
[id$='-submenu'] .topic-sub-btn:not(.selected):hover,
[id$='-submenu'] button.topic-sub-btn:not(.selected):hover,
.btn.topic-sub-btn:not(.selected):hover,
button.btn.topic-sub-btn:not(.selected):hover,
.topic-sub-btn:not(.selected):hover,
button.topic-sub-btn:not(.selected):hover {
    background: var(--surface-elevated) !important;
    border-color: var(--accent) !important;
    color: var(--text-light) !important;
    transform: translate(-0.1rem, -0.1rem) !important;
    box-shadow: 0.3rem 0.3rem 0 var(--border-strong) !important;
}

[id$='-submenu'] .btn.topic-sub-btn:not(.selected):active,
[id$='-submenu'] button.btn.topic-sub-btn:not(.selected):active,
[id$='-submenu'] .topic-sub-btn:not(.selected):active,
[id$='-submenu'] button.topic-sub-btn:not(.selected):active,
.btn.topic-sub-btn:not(.selected):active,
button.btn.topic-sub-btn:not(.selected):active,
.topic-sub-btn:not(.selected):active,
button.topic-sub-btn:not(.selected):active {
    transform: translateY(2px) !important; /* 클릭 시 아래로만 이동 */
    box-shadow: none !important;
}

.subject-btn.is-selecting {
    background: var(--primary);
    transform: none; /* 평면 디자인 */
    box-shadow: none;
    transition: all 0.1s ease-in-out;
    border: 2px solid var(--border-strong);
}

.subject-btn:active {
    transform: translateY(2px); /* 클릭 시 아래로만 이동 */
    box-shadow: none; /* 평면 디자인 */
}

.subject-btn.high-accuracy {
    border-color: #000000 !important; /* 검은색 외곽선 */
    border-width: 4px !important; /* 두꺼운 테두리 */
    color: var(--text-light);
    position: relative;
    box-shadow: none; /* 평면 디자인 */
}

.subject-btn.high-accuracy:hover {
    border-color: #000000 !important;
    transform: none; /* 평면 디자인 */
    box-shadow: none;
}

.subject-btn.high-accuracy:active {
    border-color: #000000 !important;
    transform: translateY(2px); /* 클릭 시 아래로만 이동 */
    box-shadow: none;
}
#random-subject-btn {
    background-color: var(--accent-warm);
    color: #111827;
}