:root {
    --wood-light: #DEB887;
    --wood-dark: #8B4513;
    --wood-border: #5C2A0A;
    --sky-blue: #7cd5f4;
    --grass-green: #7ecb20;
    --star-gold: #FFD700;
    --font-main: 'Nunito', sans-serif;
    --font-alt: 'Poppins', sans-serif;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: var(--font-alt);
    background: url('../assets/bg.png') no-repeat center center fixed;
    background-size: cover;
    display: flex;
    justify-content: center;
    align-items: stretch;
    height: 100dvh;
    overflow: hidden;
    user-select: none;
}

#game-wrapper {
    position: relative;
    width: 100%;
    max-width: 860px;
    display: flex;
    justify-content: center;
    align-items: stretch;
    padding: 8px;
}

/* Mascot */
#mascot-container {
    position: absolute;
    bottom: -10px;
    left: -90px;
    width: 160px;
    height: 160px;
    z-index: 50;
    pointer-events: none;
}

#mascot {
    width: 100%;
    height: 100%;
    object-fit: contain;
    filter: drop-shadow(5px 5px 10px rgba(0,0,0,0.3));
}

.idle-anim {
    animation: float 4s ease-in-out infinite;
}

.happy-anim {
    animation: jump 0.6s cubic-bezier(0.175, 0.885, 0.32, 1.275) 2;
}

.speech-bubble {
    position: absolute;
    top: -30px;
    right: -15px;
    background: #FFF;
    border: 3px solid var(--wood-border);
    border-radius: 20px;
    padding: 8px 16px;
    font-family: var(--font-main);
    font-size: 1.3rem;
    color: var(--wood-dark);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    animation: popIn 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.speech-bubble::after {
    content: '';
    position: absolute;
    bottom: -15px;
    left: 20px;
    border-width: 15px 15px 0 0;
    border-style: solid;
    border-color: #FFF transparent transparent transparent;
    display: block;
    width: 0;
}
.speech-bubble::before {
    content: '';
    position: absolute;
    bottom: -22px;
    left: 17px;
    border-width: 19px 19px 0 0;
    border-style: solid;
    border-color: var(--wood-border) transparent transparent transparent;
    display: block;
    width: 0;
    z-index: -1;
}

/* Main Board */
.wooden-board {
    width: 100%;
    height: 100%;
    background: var(--wood-light);
    border: 8px solid var(--wood-dark);
    border-radius: 26px;
    box-shadow: 0 15px 40px rgba(0,0,0,0.4), inset 0 0 30px rgba(139, 69, 19, 0.5);
    position: relative;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    background-image:
        repeating-linear-gradient(
            to right,
            transparent,
            transparent 40px,
            rgba(139, 69, 19, 0.1) 40px,
            rgba(139, 69, 19, 0.1) 42px
        );
}

.screen {
    display: none;
    padding: 16px 20px;
    flex-direction: column;
    flex: 1;
    overflow: hidden;
    align-items: center;
    justify-content: center;
}

.screen.active {
    display: flex;
}

/* Headers */
.game-header-title {
    background: #FFF;
    border: 5px solid var(--wood-dark);
    border-radius: 28px;
    padding: 8px 24px;
    margin-bottom: 16px;
    box-shadow: 0 8px 0px rgba(139, 69, 19, 0.3);
    transform: rotate(-3deg);
    flex-shrink: 0;
}

h1 {
    font-family: var(--font-main);
    font-size: 2.6rem;
    color: #FF5E7E;
    text-align: center;
    line-height: 1.1;
    text-shadow: 3px 3px 0px #FFE66D, 5px 5px 0px rgba(0,0,0,0.2);
    letter-spacing: 2px;
}

.nav-header {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
    padding: 0 6px;
    flex-shrink: 0;
}

.title-wood {
    font-family: var(--font-main);
    font-size: 1.8rem;
    color: #FFF;
    text-shadow: 3px 3px 0px var(--wood-dark), -2px -2px 0px var(--wood-dark), 2px -2px 0px var(--wood-dark), -2px 2px 0px var(--wood-dark), 2px 2px 0px var(--wood-dark);
}

/* Buttons */
.menu-options {
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 100%;
    flex: 1;
    justify-content: center;
    gap: 0;
}

.btn-menu {
    background: none;
    border: none;
    width: 100%;
    max-width: 340px;
    cursor: pointer;
    transition: transform 0.1s;
    outline: none;
    margin-bottom: 9px;
    flex-shrink: 0;
}

.btn-inner {
    background: #FF9F1C;
    border: 4px solid #FFF;
    border-radius: 20px;
    padding: 10px 22px;
    font-size: 1.75rem;
    font-family: var(--font-main);
    color: #FFF;
    text-shadow: 2px 2px 0px rgba(0,0,0,0.3);
    box-shadow: 0 7px 0px #D35400, 0 10px 12px rgba(0,0,0,0.2);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
}

.btn-wood-2 .btn-inner { background: #4ECDC4; box-shadow: 0 7px 0px #028090, 0 10px 14px rgba(0,0,0,0.2); }
.btn-wood-3 .btn-inner { background: #9D4EDD; box-shadow: 0 7px 0px #5A189A, 0 10px 14px rgba(0,0,0,0.2); }

.btn-menu:hover { transform: scale(1.04) rotate(2deg); }
.btn-menu:active .btn-inner {
    transform: translateY(10px);
    box-shadow: 0 0px 0px #D35400, 0 4px 8px rgba(0,0,0,0.2);
}

.btn-back {
    background: #FF5E7E;
    border: 3px solid #FFF;
    border-radius: 13px;
    padding: 6px 13px;
    font-family: var(--font-main);
    font-size: 1.1rem;
    color: #FFF;
    cursor: pointer;
    box-shadow: 0 4px 0px #C9184A;
    transition: all 0.1s;
}
.btn-back:active { transform: translateY(5px); box-shadow: none; }

.score-board {
    background: var(--wood-dark);
    border: 3px solid #FFF;
    border-radius: 13px;
    padding: 5px 15px;
    font-family: var(--font-main);
    font-size: 1.3rem;
    color: #FFF;
    box-shadow: 0 4px 0px #5C2A0A;
    display: flex;
    align-items: center;
    gap: 6px;
}

.star-icon { font-size: 1.5rem; filter: drop-shadow(2px 2px 0px rgba(0,0,0,0.5)); }

.stage-options {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
    align-content: center;
    flex: 1;
    overflow-y: auto;
    padding: 4px 2px;
}

.btn-stage {
    background: #32E0C4;
    border: 3px solid #FFF;
    border-radius: 16px;
    padding: 9px 20px;
    font-family: var(--font-main);
    font-size: 1.25rem;
    color: #FFF;
    cursor: pointer;
    box-shadow: 0 5px 0px #028090;
    transition: all 0.1s;
    text-shadow: 2px 2px 0px rgba(0,0,0,0.2);
}
.btn-stage:hover { transform: scale(1.05) rotate(-2deg); }
.btn-stage:active { transform: translateY(7px); box-shadow: none; }

/* Game Area */
#game-container {
    width: 100%;
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    overflow: hidden;
    min-height: 0;
}

#screen-category {
    justify-content: flex-start;
}

.game-header-board {
    background: #FFF;
    border: 4px solid var(--wood-dark);
    border-radius: 18px;
    padding: 8px 22px;
    text-align: center;
    margin-bottom: 10px;
    box-shadow: 0 6px 0px rgba(139, 69, 19, 0.2);
    flex-shrink: 0;
    width: 100%;
}

#stage-title { font-family: var(--font-alt); font-size: 0.85rem; color: #666; margin-bottom: 2px; font-weight: bold; }
.prompt { font-family: var(--font-main); font-size: 1.85rem; color: #E63946; }

.game-area {
    background: rgba(255, 255, 255, 0.4);
    border: 4px dashed var(--wood-dark);
    border-radius: 18px;
    padding: 14px;
    width: 100%;
    flex: 1;
    min-height: 0;
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    justify-content: center;
    align-items: center;
    overflow-y: auto;
    overflow-x: hidden;
}

/* Playful Bubbles for objects */
.object-item {
    font-size: 2.5rem;
    cursor: pointer;
    background: #FFF;
    border: 3px solid var(--sky-blue);
    border-radius: 50%;
    width: 64px;
    height: 64px;
    display: flex;
    justify-content: center;
    align-items: center;
    box-shadow: 0 5px 10px rgba(0,0,0,0.1), inset 0 -3px 6px rgba(0,0,0,0.05);
    transition: all 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    user-select: none;
    position: relative;
}

.object-item:hover { transform: scale(1.1) rotate(10deg); border-color: var(--grass-green); }

.object-item.selected {
    background: #E8F8F5;
    border-color: var(--grass-green);
    transform: translateY(-12px) scale(1.12);
    box-shadow: 0 12px 18px rgba(0,0,0,0.2), inset 0 -4px 8px rgba(0,0,0,0.05);
}

.object-item.selected::after {
    content: '✅';
    position: absolute;
    bottom: -13px;
    right: -9px;
    font-size: 1.7rem;
    animation: popIn 0.3s ease forwards;
    filter: drop-shadow(0 2px 4px rgba(0,0,0,0.2));
}

/* Game Controls */
.game-controls { display: flex; gap: 12px; margin-top: 10px; flex-shrink: 0; }

.btn-action {
    padding: 8px 24px;
    font-size: 1.4rem;
    font-family: var(--font-main);
    border: 4px solid #FFF;
    border-radius: 18px;
    color: #FFF;
    cursor: pointer;
    box-shadow: 0 7px 0px rgba(0,0,0,0.2);
    transition: all 0.1s;
    text-shadow: 2px 2px 0px rgba(0,0,0,0.3);
}

.btn-submit { background: var(--grass-green); box-shadow: 0 8px 0px #558B16; }
.btn-submit:active { transform: translateY(8px); box-shadow: none; }

.btn-next { background: #FF9F1C; box-shadow: 0 8px 0px #D35400; }
.btn-next:active { transform: translateY(8px); box-shadow: none; }

/* Inputs */
.fraction-input {
    width: 72px;
    height: 58px;
    font-size: 2.2rem;
    text-align: center;
    border: 4px solid var(--sky-blue);
    border-radius: 13px;
    font-family: var(--font-main);
    color: var(--wood-dark);
    box-shadow: inset 0 3px 7px rgba(0,0,0,0.1);
}
.fraction-input:focus { outline: none; border-color: var(--grass-green); }

/* Fractions */
.fraction {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    font-size: 2.2rem;
    font-family: var(--font-main);
    color: var(--wood-dark);
    margin: 0 8px;
    line-height: 1;
}
.fraction-top { border-bottom: 4px solid var(--wood-dark); padding: 0 6px; }
.fraction-bottom { padding: 0 6px; }

/* Multiple Choice */
.choice-container { display: flex; gap: 14px; flex-wrap: wrap; justify-content: center; }

.btn-choice {
    background: #FFF;
    border: 4px solid var(--wood-dark);
    border-radius: 18px;
    padding: 12px 22px;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    box-shadow: 0 6px 0px rgba(139, 69, 19, 0.3);
    margin: 4px;
}

.btn-choice:hover { transform: translateY(-8px) scale(1.04); }
.btn-choice:active { transform: translateY(8px); box-shadow: none; }

.btn-choice.correct { background: var(--grass-green); border-color: #FFF; }
.btn-choice.correct .fraction, .btn-choice.correct .fraction-top { color: #FFF; border-color: #FFF; }
.btn-choice.wrong { background: #EF476F; border-color: #FFF; }
.btn-choice.wrong .fraction, .btn-choice.wrong .fraction-top { color: #FFF; border-color: #FFF; }

/* Comparing Signs */
.compare-container {
    background: #FFF;
    border: 5px solid var(--sky-blue);
    border-radius: 26px;
    padding: 16px 28px;
    display: flex;
    align-items: center;
    gap: 28px;
    box-shadow: 0 8px 18px rgba(0,0,0,0.1);
}

.btn-sign {
    font-size: 2.6rem;
    width: 66px;
    height: 66px;
    border-radius: 50%;
    border: 4px solid #FFF;
    background: var(--star-gold);
    color: #D35400;
    cursor: pointer;
    box-shadow: 0 7px 0px #E67E22;
    transition: all 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    font-family: var(--font-main);
}

.btn-sign:hover { transform: scale(1.12) rotate(15deg); }
.btn-sign:active { transform: translateY(9px); box-shadow: none; }
.btn-sign.correct { background: var(--grass-green); color: #FFF; box-shadow: 0 8px 0px #558B16; }
.btn-sign.wrong { background: #EF476F; color: #FFF; box-shadow: 0 8px 0px #C9184A; }

/* Compare sign box (empty box in the middle) */
.compare-sign-box {
    width: 66px;
    height: 66px;
    border: 4px dashed var(--wood-dark);
    border-radius: 16px;
    background: rgba(255, 255, 255, 0.6);
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-main);
    font-size: 2.4rem;
    color: var(--wood-dark);
    flex-shrink: 0;
    transition: background 0.2s, border-color 0.2s;
}

.compare-sign-box.sign-correct {
    border-style: solid;
    border-color: var(--grass-green);
    background: rgba(126, 203, 32, 0.18);
    color: #3a8a00;
    animation: popIn 0.35s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

/* Sign buttons row below */
.sign-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
}

/* Pie Charts */
.pie-chart {
    width: 96px;
    height: 96px;
    border-radius: 50%;
    background: #E0E0E0;
    border: 4px solid var(--wood-dark);
    box-shadow: 0 6px 10px rgba(0,0,0,0.2);
}

/* Overlay & Celebration */
.overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.7);
    backdrop-filter: blur(8px);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 100;
}

.celebration-box {
    background: url('https://www.transparenttextures.com/patterns/cubes.png'), var(--sky-blue);
    border: 8px solid #FFF;
    padding: 28px 40px;
    border-radius: 32px;
    text-align: center;
    box-shadow: 0 0 40px rgba(255,255,255,0.5);
    animation: popIn 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.celebration-box h2 { font-size: 3rem; color: #FFF; margin-bottom: 6px; }
.celebration-box p { font-size: 1.7rem; font-family: var(--font-main); color: #FFF; margin-bottom: 12px; text-shadow: 2px 2px 0px rgba(0,0,0,0.2); }

.stars-container { font-size: 3rem; margin-bottom: 16px; animation: bounce 2s infinite; }

/* ── Category 4: Σειροθέτηση ─────────────────────────── */

/* Number Line */
.nl-container {
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.nl-bar {
    display: flex;
    align-items: flex-start;
    gap: 5px;
}

.nl-label-end {
    font-family: var(--font-main);
    font-size: 1.3rem;
    color: var(--wood-dark);
    min-width: 22px;
    text-align: center;
    padding-top: 5px;
}

.nl-track {
    flex: 1;
    position: relative;
    height: 116px;
}

.nl-track::before {
    content: '';
    position: absolute;
    top: 10px;
    left: 0;
    right: 0;
    height: 6px;
    background: var(--wood-dark);
    border-radius: 4px;
    z-index: 0;
}

.nl-slot {
    position: absolute;
    top: 0;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    z-index: 1;
}

.nl-tick {
    width: 5px;
    height: 32px;
    background: var(--wood-dark);
    border-radius: 3px;
}

.nl-drop-box {
    width: 60px;
    min-height: 64px;
    margin-top: 3px;
    border: 3px dashed var(--wood-dark);
    border-radius: 12px;
    background: rgba(255, 255, 255, 0.55);
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 3px;
    transition: background 0.2s, border-color 0.2s;
}

.nl-drop-box.drag-over {
    background: rgba(126, 203, 32, 0.25);
    border-color: var(--grass-green);
    border-style: solid;
}

.nl-drop-box.slot-correct {
    background: rgba(126, 203, 32, 0.2);
    border-color: var(--grass-green);
    border-style: solid;
}

/* Fraction bank (shared by stages 1 & 3) */
.frac-bank {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
    min-height: 64px;
    padding: 8px 12px;
    background: rgba(255, 255, 255, 0.3);
    border: 3px dashed var(--wood-dark);
    border-radius: 14px;
    transition: background 0.2s;
}

/* Draggable fraction card */
.drag-frac {
    background: #FFF;
    border: 3px solid var(--sky-blue);
    border-radius: 14px;
    padding: 5px 12px;
    cursor: grab;
    box-shadow: 0 4px 0px rgba(0, 0, 0, 0.15);
    transition: transform 0.15s, border-color 0.15s;
    user-select: none;
    touch-action: none;
    display: flex;
    align-items: center;
    justify-content: center;
}

.drag-frac:hover {
    transform: scale(1.07) translateY(-3px);
    border-color: var(--grass-green);
}

.drag-frac.frac-dragging {
    opacity: 0.35;
    cursor: grabbing;
}

.drag-frac .fraction {
    font-size: 1.45rem;
    margin: 0 2px;
}

.drag-frac .fraction-top {
    border-bottom-width: 3px;
    padding: 0 4px;
}

.drag-frac .fraction-bottom {
    padding: 0 4px;
}

/* Stage 2 - Three Boxes */
.s2-container {
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.s2-boxes {
    display: flex;
    gap: 10px;
    justify-content: center;
}

.s2-box {
    flex: 1;
    min-width: 100px;
    max-width: 190px;
    background: rgba(255, 255, 255, 0.5);
    border: 3px solid var(--wood-dark);
    border-radius: 18px;
    padding: 8px 7px;
    display: flex;
    flex-direction: column;
    gap: 7px;
    min-height: 130px;
    transition: background 0.2s, border-color 0.2s;
}

.s2-box.drag-over {
    background: rgba(126, 203, 32, 0.22);
    border-color: var(--grass-green);
}

.s2-box.box-correct {
    background: rgba(126, 203, 32, 0.2);
    border-color: var(--grass-green);
}

.s2-label {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2px;
    font-family: var(--font-alt);
    font-size: 0.8rem;
    font-weight: bold;
    color: var(--wood-dark);
    border-bottom: 2px solid var(--wood-dark);
    padding-bottom: 5px;
}

.s2-label .fraction {
    font-size: 1.25rem;
}

.s2-label .fraction-top {
    padding: 0 3px;
    border-bottom-width: 2px;
}

.s2-label .fraction-bottom {
    padding: 0 3px;
}

.box-cmp {
    font-size: 0.75rem;
    color: #666;
}

.s2-content {
    flex: 1;
    display: flex;
    flex-wrap: wrap;
    gap: 5px;
    justify-content: center;
    align-items: flex-start;
    padding: 3px 2px;
    min-height: 60px;
}

/* Menu button colors for categories 4 & 5 */
.btn-wood-4 .btn-inner { background: #E05CFF; box-shadow: 0 7px 0px #9B1FD8, 0 10px 12px rgba(0,0,0,0.2); }
.btn-wood-5 .btn-inner { background: #26de81; box-shadow: 0 7px 0px #20bf6b, 0 10px 12px rgba(0,0,0,0.2); }

/* Problem card (Category 5) */
.problem-card {
    background: #FFF;
    border: 4px solid var(--wood-dark);
    border-radius: 18px;
    padding: 14px 20px;
    text-align: center;
    box-shadow: 0 5px 0px rgba(139,69,19,0.2);
}

.problem-body {
    font-family: var(--font-alt);
    font-size: 1.1rem;
    color: #333;
    line-height: 1.6;
    word-break: break-word;
}

.problem-q {
    font-family: var(--font-main);
    font-size: 1.35rem;
    color: var(--wood-dark);
    margin-top: 8px;
}

/* Numpad */
.input-numpad-row {
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: center;
    align-items: flex-start;
    gap: 16px;
    width: 100%;
}

.numpad {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 5px;
    background: rgba(255, 255, 255, 0.6);
    border: 3px solid var(--wood-dark);
    border-radius: 18px;
    padding: 8px;
    box-shadow: 0 6px 12px rgba(0,0,0,0.15);
}

.numpad-btn {
    width: 38px;
    height: 38px;
    font-family: var(--font-main);
    font-size: 1.25rem;
    background: #FFF;
    border: 3px solid var(--wood-dark);
    border-radius: 11px;
    color: var(--wood-dark);
    cursor: pointer;
    box-shadow: 0 4px 0px rgba(139,69,19,0.35);
    transition: all 0.1s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.numpad-btn:hover { transform: scale(1.07); }
.numpad-btn:active { transform: translateY(4px); box-shadow: none; }

.numpad-del {
    background: #FF9F1C;
    color: #FFF;
    border-color: #D35400;
    box-shadow: 0 4px 0px #D35400;
}

.fraction-input.input-active {
    border-color: var(--grass-green);
    box-shadow: 0 0 0 3px rgba(126, 203, 32, 0.35), inset 0 3px 7px rgba(0,0,0,0.1);
}

/* Utilities */
.hidden { display: none !important; }

@keyframes popIn {
    0% { transform: scale(0) rotate(-15deg); }
    80% { transform: scale(1.1) rotate(5deg); }
    100% { transform: scale(1) rotate(0deg); }
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-15px); }
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-20px); }
}

@keyframes jump {
    0%, 100% { transform: translateY(0) scale(1); }
    50% { transform: translateY(-40px) scale(1.1); }
}

.bounce-anim { animation: bounce 2s ease-in-out infinite; }
.shake { animation: shake 0.5s cubic-bezier(.36,.07,.19,.97) both; }

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-20px) rotate(-10deg); }
    75% { transform: translateX(20px) rotate(10deg); }
}

/* ── Mobile: all content fits on screen without scrolling ──── */
@media (max-width: 500px) {
    /* Nav header */
    .nav-header { margin-bottom: 8px; }
    .title-wood { font-size: 1.4rem; }

    /* Game header board */
    .game-header-board { padding: 5px 12px; margin-bottom: 6px; }
    .prompt { font-size: 1.4rem; }

    /* Fractions & inputs */
    .fraction { font-size: 1.6rem; }
    .fraction-input { width: 54px; height: 46px; font-size: 1.75rem; }

    /* Action buttons */
    .btn-action { padding: 6px 16px; font-size: 1.15rem; }

    /* Category 1: object items */
    .object-item { width: 52px; height: 52px; font-size: 1.9rem; }

    /* Category 2: pie charts & choice buttons */
    .pie-chart { width: 58px; height: 58px; }
    .btn-choice .pie-chart { width: 32px !important; height: 32px !important; margin-top: 4px !important; }
    .btn-choice { padding: 5px 10px; margin: 2px; }

    /* Category 3: comparison */
    .compare-container { gap: 14px; padding: 10px 16px; }
    .compare-box .pie-chart { margin-top: 6px !important; }
    .btn-sign { width: 52px; height: 52px; font-size: 1.9rem; }
    .compare-sign-box { width: 52px; height: 52px; font-size: 2rem; }

    /* Category 4: number line */
    .nl-track { height: 95px; }
    .nl-drop-box { width: 46px; min-height: 54px; }
    .drag-frac { padding: 4px 8px; }
    .drag-frac .fraction { font-size: 1.15rem; }

    /* Category 4 Stage 2: three boxes */
    .s2-boxes { gap: 6px; }
    .s2-box { min-width: 80px; padding: 5px 4px; min-height: 90px; }
    .s2-label .fraction { font-size: 1.05rem; }

    /* Category 5: problem card & compact numpad */
    .problem-card { padding: 10px 14px; }
    .problem-body { font-size: 1rem; }
    .numpad { gap: 4px; padding: 6px; }
    .numpad-btn { width: 34px; height: 34px; font-size: 1.1rem; }
    .fraction-input { height: 40px; }
    .input-numpad-row { gap: 10px; }
}