/* ============================================
   Math Arena - Cartoony Theme
   Game + Calculator Styles
   ============================================ */

:root {
    --body-blue: #3a7bd5;
    --body-blue-light: #5a9be6;
    --faceplate: #d6e6f5;
    --display-bg: #c8dcc0;
    --display-border: #2d2d2d;
    --display-text: #1a1a1a;
    --btn-num-bg: #ffffff;
    --btn-num-border: #2d2d2d;
    --btn-num-hover: #f0f0f0;
    --btn-op-bg: #ff9800;
    --btn-op-border: #e68900;
    --btn-op-hover: #ffb74d;
    --btn-func-bg: #64b5f6;
    --btn-func-border: #42a5f5;
    --btn-func-hover: #90caf9;
    --btn-mem-bg: #ce93d8;
    --btn-mem-border: #ba68c8;
    --btn-mem-hover: #e1bee7;
    --btn-eq-bg: #66bb6a;
    --btn-eq-border: #4caf50;
    --btn-eq-hover: #a5d6a7;
    --btn-ac-bg: #ef5350;
    --btn-ac-border: #e53935;
    --btn-ac-hover: #ef9a9a;
    --btn-del-bg: #ffa726;
    --btn-del-border: #fb8c00;
    --btn-shift-bg: #ffee58;
    --btn-shift-border: #fdd835;
    --btn-nav-bg: #b0bec5;
    --btn-nav-border: #90a4ae;
    --btn-mode-bg: #26a69a;
    --btn-mode-border: #00897b;
    --shadow-dark: rgba(0,0,0,0.35);
    --shadow-light: rgba(255,255,255,0.2);
    --font-main: 'Fredoka', sans-serif;
    --border-radius: 12px;
    --btn-radius: 10px;
    --green: #66bb6a;
    --red: #ef5350;
    --gold: #ffd54f;
    --purple: #7c4dff;
}

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

/* Exponent styling */
sup {
    font-size: 0.7em;
    vertical-align: super;
    line-height: 0;
    color: var(--gold);
    font-weight: 600;
}

html, body {
    width: 100%;
    min-height: 100vh;
    font-family: var(--font-main);
    overflow-x: hidden;
}

body {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    flex-direction: column;
    align-items: center;
    position: relative;
}

/* Background decoration */
.bg-decor {
    position: fixed; inset: 0;
    pointer-events: none; overflow: hidden; z-index: 0;
}
.bg-sym {
    position: absolute;
    left: var(--x); top: var(--y);
    font-size: var(--s);
    color: rgba(255,255,255,0.08);
    animation: floaty 6s ease-in-out infinite;
    animation-delay: var(--d);
    font-family: serif;
}
@keyframes floaty {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    50% { transform: translateY(-18px) rotate(8deg); }
}

/* ============================================
   NAVIGATION
   ============================================ */
.top-nav {
    position: fixed; top: 0; left: 0; right: 0;
    z-index: 50;
    display: flex; align-items: center; justify-content: space-between;
    padding: 10px 20px;
    background: rgba(30, 30, 60, 0.85);
    backdrop-filter: blur(8px);
    border-bottom: 3px solid rgba(255,255,255,0.1);
}

.nav-logo {
    font-size: 1.3rem; font-weight: 700; color: #fff;
    letter-spacing: 1px;
}

.nav-tabs { display: flex; gap: 6px; }

.nav-tab {
    font-family: var(--font-main);
    font-size: 0.85rem; font-weight: 600;
    padding: 7px 18px;
    border: 2px solid rgba(255,255,255,0.2);
    border-radius: 20px;
    background: transparent; color: rgba(255,255,255,0.6);
    cursor: pointer; transition: all 0.2s;
}
.nav-tab:hover { background: rgba(255,255,255,0.1); color: #fff; }
.nav-tab.active {
    background: var(--purple); color: #fff;
    border-color: var(--purple);
}

/* ============================================
   VIEW MANAGEMENT
   ============================================ */
.view {
    display: none;
    width: 100%; min-height: 100vh;
    padding-top: 60px;
    position: relative; z-index: 1;
}
.view.active { display: flex; justify-content: center; align-items: flex-start; }

.game-view { align-items: center; padding: 70px 16px 30px; }
.calc-view { align-items: center; padding: 70px 16px 30px; }

/* Screen management within game view */
.screen { display: none; width: 100%; max-width: 520px; }
.screen.active { display: block; animation: screenIn 0.35s cubic-bezier(0.34, 1.56, 0.64, 1); }

@keyframes screenIn {
    0% { transform: scale(0.9) translateY(20px); opacity: 0; }
    100% { transform: scale(1) translateY(0); opacity: 1; }
}

/* ============================================
   GAME - MENU SCREEN
   ============================================ */
.menu-hero {
    text-align: center; margin-bottom: 28px;
}
.menu-hero h1 {
    font-size: 2.6rem; font-weight: 700; color: #fff;
    text-shadow: 0 3px 12px rgba(0,0,0,0.3);
    letter-spacing: 1px;
}
.tagline {
    font-size: 1rem; color: rgba(255,255,255,0.7);
    margin-top: 4px;
}

/* ---- Carousel ---- */
.mode-carousel {
    background: rgba(255,255,255,0.1);
    border: 3px solid rgba(255,255,255,0.15);
    border-radius: 20px;
    overflow: hidden;
    backdrop-filter: blur(4px);
}

.carousel-tabs {
    display: flex;
    border-bottom: 2px solid rgba(255,255,255,0.1);
}

.carousel-tab {
    flex: 1;
    font-family: var(--font-main);
    font-size: 0.95rem; font-weight: 600;
    padding: 12px 16px;
    border: none;
    background: transparent;
    color: rgba(255,255,255,0.45);
    cursor: pointer;
    transition: all 0.25s;
    position: relative;
}
.carousel-tab::after {
    content: '';
    position: absolute;
    bottom: -2px; left: 15%; right: 15%;
    height: 3px; border-radius: 2px;
    background: var(--gold);
    transform: scaleX(0);
    transition: transform 0.25s cubic-bezier(0.34, 1.56, 0.64, 1);
}
.carousel-tab:hover { color: rgba(255,255,255,0.7); }
.carousel-tab.active {
    color: #fff;
}
.carousel-tab.active::after {
    transform: scaleX(1);
}

.carousel-track {
    position: relative;
    min-height: 160px;
}

.carousel-panel {
    display: none;
    padding: 20px;
    animation: panelFade 0.3s ease;
}
.carousel-panel.active {
    display: block;
}

@keyframes panelFade {
    from { opacity: 0; transform: translateY(8px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ---- Table Picker ---- */
.table-picker {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 6px;
}

.tp-btn {
    font-family: var(--font-main);
    font-size: 0.9rem; font-weight: 600;
    padding: 10px 4px;
    border: 3px solid rgba(255,255,255,0.2);
    border-radius: 10px;
    background: rgba(255,255,255,0.06);
    color: rgba(255,255,255,0.7);
    cursor: pointer;
    transition: all 0.15s;
    box-shadow: 0 3px 0 rgba(0,0,0,0.12);
    text-align: center;
}
.tp-btn:hover {
    background: rgba(255,255,255,0.14);
    transform: translateY(-1px);
}
.tp-btn:active {
    transform: translateY(2px);
    box-shadow: 0 1px 0 rgba(0,0,0,0.12);
}
.tp-btn.selected {
    background: var(--gold);
    color: #333; font-weight: 700;
    border-color: #ffc107;
    box-shadow: 0 3px 0 rgba(0,0,0,0.2), 0 0 14px rgba(255,213,79,0.3);
}
.tp-btn[data-table="all"] {
    grid-column: span 1;
    font-size: 0.8rem;
}

.option-group {
    margin-bottom: 18px;
}
.option-group:last-child { margin-bottom: 0; }
.option-group h3 {
    font-size: 0.85rem; font-weight: 600;
    color: rgba(255,255,255,0.8);
    margin-bottom: 8px; text-transform: uppercase;
    letter-spacing: 1px;
}

.option-row {
    display: flex; flex-wrap: wrap; gap: 8px;
}

.opt-btn {
    font-family: var(--font-main);
    font-size: 0.85rem; font-weight: 500;
    padding: 9px 16px;
    border: 3px solid rgba(255,255,255,0.25);
    border-radius: 12px;
    background: rgba(255,255,255,0.08);
    color: rgba(255,255,255,0.8);
    cursor: pointer; transition: all 0.15s;
    box-shadow: 0 3px 0 rgba(0,0,0,0.15);
}
.opt-btn:hover {
    background: rgba(255,255,255,0.15);
    transform: translateY(-1px);
}
.opt-btn:active {
    transform: translateY(2px);
    box-shadow: 0 1px 0 rgba(0,0,0,0.15);
}
.opt-btn.selected {
    background: var(--gold);
    color: #333; font-weight: 600;
    border-color: #ffc107;
    box-shadow: 0 3px 0 rgba(0,0,0,0.2), 0 0 12px rgba(255,213,79,0.3);
}

.start-btn {
    display: block; width: 100%;
    margin-top: 24px;
    font-family: var(--font-main);
    font-size: 1.3rem; font-weight: 700;
    padding: 16px;
    border: 4px solid #4caf50;
    border-radius: 16px;
    background: var(--green);
    color: #fff;
    cursor: pointer;
    box-shadow: 0 5px 0 rgba(0,0,0,0.25), 0 8px 20px rgba(0,0,0,0.2);
    transition: transform 0.1s, box-shadow 0.1s;
    text-shadow: 0 2px 4px rgba(0,0,0,0.2);
    letter-spacing: 1px;
}
.start-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 7px 0 rgba(0,0,0,0.25), 0 10px 24px rgba(0,0,0,0.25);
}
.start-btn:active {
    transform: translateY(4px);
    box-shadow: 0 1px 0 rgba(0,0,0,0.25);
}

/* ============================================
   GAME - GAME SCREEN
   ============================================ */
.game-hud {
    display: flex; justify-content: space-between;
    margin-bottom: 10px;
}
.hud-item {
    display: flex; flex-direction: column; align-items: center;
    background: rgba(255,255,255,0.1);
    border: 2px solid rgba(255,255,255,0.15);
    border-radius: 12px;
    padding: 8px 18px;
    min-width: 90px;
}
.hud-label {
    font-size: 0.65rem; font-weight: 500;
    color: rgba(255,255,255,0.5);
    text-transform: uppercase; letter-spacing: 1px;
}
.hud-value {
    font-size: 1.3rem; font-weight: 700; color: #fff;
}

.progress-track {
    width: 100%; height: 10px;
    background: rgba(255,255,255,0.12);
    border-radius: 5px;
    margin-bottom: 20px;
    overflow: hidden;
    border: 2px solid rgba(255,255,255,0.1);
}
.progress-fill {
    height: 100%; width: 0%;
    background: linear-gradient(90deg, var(--green), #81c784);
    border-radius: 3px;
    transition: width 0.3s ease;
}

.question-card {
    background: rgba(255,255,255,0.12);
    border: 3px solid rgba(255,255,255,0.2);
    border-radius: 20px;
    padding: 36px 20px;
    text-align: center;
    margin-bottom: 20px;
    transition: border-color 0.3s, background 0.3s;
}
.question-card.correct {
    border-color: var(--green);
    background: rgba(102,187,106,0.15);
}
.question-card.wrong {
    border-color: var(--red);
    background: rgba(239,83,80,0.15);
}

.question-text {
    font-size: 2.4rem; font-weight: 700; color: #fff;
    text-shadow: 0 2px 8px rgba(0,0,0,0.2);
    letter-spacing: 2px;
    display: flex; align-items: center; justify-content: center; flex-wrap: wrap; gap: 6px;
    flex-direction: column;
}
.practice-q-svg { margin-bottom: 8px; display: flex; justify-content: center; }
.practice-q-svg svg { max-width: 280px; }
.practice-q-detail { font-size: 0.85rem; color: rgba(255,255,255,0.5); font-style: italic; margin-bottom: 4px; font-weight: 400; letter-spacing: 0; }

/* Stacked fraction display inside questions */
.frac-display {
    display: inline-flex; flex-direction: column; align-items: center;
    vertical-align: middle; margin: 0 4px; line-height: 1;
}
.frac-num, .frac-den {
    font-size: 0.65em; padding: 0 4px;
}
.frac-num {
    border-bottom: 3px solid #fff;
}

.answer-area {
    display: flex; gap: 10px;
    margin-bottom: 14px;
}

.answer-input {
    flex: 1;
    font-family: var(--font-main);
    font-size: 1.4rem; font-weight: 600;
    padding: 14px 18px;
    border: 3px solid rgba(255,255,255,0.3);
    border-radius: 14px;
    background: rgba(255,255,255,0.12);
    color: #fff;
    outline: none;
    text-align: center;
    transition: border-color 0.2s, background 0.2s;
}
.answer-input::placeholder { color: rgba(255,255,255,0.3); }
.answer-input:focus {
    border-color: var(--gold);
    background: rgba(255,255,255,0.18);
}
.answer-input.correct {
    border-color: var(--green);
    background: rgba(102,187,106,0.2);
}
.answer-input.wrong {
    border-color: var(--red);
    background: rgba(239,83,80,0.2);
}

.submit-btn {
    font-family: var(--font-main);
    font-size: 1.1rem; font-weight: 700;
    padding: 14px 28px;
    border: 3px solid #4caf50;
    border-radius: 14px;
    background: var(--green);
    color: #fff;
    cursor: pointer;
    box-shadow: 0 4px 0 rgba(0,0,0,0.2);
    transition: transform 0.1s, box-shadow 0.1s;
    text-shadow: 0 1px 2px rgba(0,0,0,0.2);
}
.submit-btn:hover { transform: translateY(-1px); }
.submit-btn:active {
    transform: translateY(3px);
    box-shadow: 0 1px 0 rgba(0,0,0,0.2);
}

.feedback {
    text-align: center;
    font-size: 1.1rem; font-weight: 600;
    min-height: 1.6em;
    color: rgba(255,255,255,0.8);
    margin-bottom: 10px;
    transition: color 0.2s;
}
.feedback.correct { color: var(--green); }
.feedback.wrong { color: var(--red); }
.feedback .frac-display { margin: 0 3px; }
.feedback .frac-num, .feedback .frac-den { font-size: 0.7em; }

.quit-btn {
    display: block; margin: 10px auto 0;
    font-family: var(--font-main);
    font-size: 0.8rem; font-weight: 500;
    padding: 8px 20px;
    border: 2px solid rgba(255,255,255,0.2);
    border-radius: 10px;
    background: transparent;
    color: rgba(255,255,255,0.5);
    cursor: pointer; transition: all 0.15s;
}
.quit-btn:hover { border-color: var(--red); color: var(--red); }

/* ============================================
   GAME - RESULTS SCREEN
   ============================================ */
.results-card {
    background: rgba(255,255,255,0.12);
    border: 3px solid rgba(255,255,255,0.2);
    border-radius: 20px;
    padding: 28px 24px;
    text-align: center;
    margin-bottom: 16px;
}
.results-title {
    font-size: 1.6rem; font-weight: 700; color: #fff;
    margin-bottom: 16px;
}

.score-circle {
    width: 130px; height: 130px;
    border-radius: 50%;
    background: rgba(255,255,255,0.08);
    border: 5px solid var(--gold);
    display: flex; align-items: center; justify-content: center;
    margin: 0 auto 20px;
    box-shadow: 0 0 20px rgba(255,213,79,0.2);
}
.score-pct {
    font-size: 2rem; font-weight: 700; color: var(--gold);
}

.results-stats { margin-bottom: 20px; }
.stat-row {
    display: flex; justify-content: space-between;
    padding: 8px 12px;
    border-bottom: 1px solid rgba(255,255,255,0.08);
    font-size: 0.95rem; color: rgba(255,255,255,0.7);
}
.stat-val { font-weight: 600; color: #fff; }
.correct-val { color: var(--green); }
.wrong-val { color: var(--red); }

.results-actions { display: flex; gap: 10px; }
.res-btn {
    flex: 1;
    font-family: var(--font-main);
    font-size: 0.9rem; font-weight: 600;
    padding: 12px;
    border: 3px solid rgba(255,255,255,0.2);
    border-radius: 12px;
    background: rgba(255,255,255,0.08);
    color: #fff;
    cursor: pointer; transition: all 0.15s;
    box-shadow: 0 3px 0 rgba(0,0,0,0.15);
}
.res-btn:hover { background: rgba(255,255,255,0.15); transform: translateY(-1px); }
.res-btn:active { transform: translateY(2px); box-shadow: 0 1px 0 rgba(0,0,0,0.15); }
.res-btn.primary {
    background: var(--green); border-color: #4caf50;
}

.review-details {
    background: rgba(255,255,255,0.08);
    border: 2px solid rgba(255,255,255,0.12);
    border-radius: 14px;
    padding: 0;
}
.review-details summary {
    padding: 12px 16px;
    font-size: 0.9rem; font-weight: 600;
    color: rgba(255,255,255,0.7);
    cursor: pointer;
}
.review-details summary:hover { color: #fff; }

.review-list { padding: 0 16px 12px; }
.review-item {
    display: flex; justify-content: space-between; align-items: center;
    padding: 6px 0;
    border-bottom: 1px solid rgba(255,255,255,0.06);
    font-size: 0.85rem;
}
.review-item .ri-q { color: rgba(255,255,255,0.6); display: flex; align-items: center; gap: 4px; }
.review-item .ri-a { font-weight: 600; display: flex; align-items: center; gap: 4px; }
.review-item .ri-a.right { color: var(--green); }
.review-item .ri-a.wrong { color: var(--red); }
.ri-was { color: rgba(255,255,255,0.4); font-weight: 400; }
.review-item .frac-display { margin: 0 2px; }
.review-item .frac-num, .review-item .frac-den { font-size: 0.75em; }

/* ============================================
   LEARN VIEW
   ============================================ */
.learn-view {
    max-width: 1100px; margin: 0 auto;
    padding: 80px 20px 30px;
    width: 100%;
}
.learn-header {
    text-align: center; margin-bottom: 24px;
}
.learn-header h1 {
    font-size: 2.2rem; color: #fff; margin-bottom: 4px;
}
.learn-sub {
    color: rgba(255,255,255,0.6); font-size: 1rem;
}
.learn-layout {
    display: flex; gap: 20px; align-items: flex-start;
}
/* Sidebar */
.learn-sidebar {
    width: 220px; flex-shrink: 0;
    background: rgba(255,255,255,0.08); border-radius: 16px;
    padding: 12px; border: 2px solid rgba(255,255,255,0.1);
    max-height: calc(100vh - 160px); overflow-y: auto;
}
.learn-cat-group { margin-bottom: 8px; }
.learn-cat-btn {
    width: 100%; text-align: left; padding: 10px 12px;
    background: none; border: none; color: rgba(255,255,255,0.7);
    font-family: var(--font-main); font-size: 0.92rem; font-weight: 600;
    cursor: pointer; border-radius: 10px; transition: all 0.2s;
}
.learn-cat-btn:hover { background: rgba(255,255,255,0.08); color: #fff; }
.learn-cat-btn.active { background: rgba(255,255,255,0.12); color: var(--gold); }
.learn-topic-list { display: none; padding: 2px 0 4px 8px; }
.learn-topic-list.open { display: block; }
.learn-topic-btn {
    width: 100%; text-align: left; padding: 7px 10px;
    background: none; border: none; color: rgba(255,255,255,0.55);
    font-family: var(--font-main); font-size: 0.82rem; font-weight: 400;
    cursor: pointer; border-radius: 8px; transition: all 0.15s;
}
.learn-topic-btn:hover { background: rgba(255,255,255,0.06); color: rgba(255,255,255,0.9); }
.learn-topic-btn.active { color: var(--gold); font-weight: 500; background: rgba(255,213,79,0.08); }

/* Content area */
.learn-content {
    flex: 1; min-width: 0;
    background: rgba(255,255,255,0.06); border-radius: 16px;
    padding: 24px; border: 2px solid rgba(255,255,255,0.08);
    min-height: 400px;
}
.learn-welcome {
    text-align: center; padding: 40px 20px;
}
.learn-welcome h2 { color: #fff; font-size: 1.6rem; margin-bottom: 10px; }
.learn-welcome p { color: rgba(255,255,255,0.6); font-size: 0.95rem; line-height: 1.6; }

/* Lesson view */
.lesson-title {
    font-size: 1.5rem; color: var(--gold); margin-bottom: 16px;
    padding-bottom: 10px; border-bottom: 2px solid rgba(255,255,255,0.1);
}
.lesson-tabs {
    display: flex; gap: 8px; margin-bottom: 20px;
}
.lesson-tab {
    padding: 8px 18px; border: 2px solid rgba(255,255,255,0.15);
    background: rgba(255,255,255,0.05); color: rgba(255,255,255,0.6);
    border-radius: 10px; font-family: var(--font-main);
    font-size: 0.85rem; font-weight: 500; cursor: pointer; transition: all 0.2s;
}
.lesson-tab:hover { border-color: rgba(255,255,255,0.25); color: #fff; }
.lesson-tab.active {
    background: var(--gold); color: #1a1a1a; border-color: var(--gold); font-weight: 600;
}
.lesson-body {
    color: rgba(255,255,255,0.85); font-size: 0.92rem; line-height: 1.7;
}
.lesson-body h3 {
    color: #fff; font-size: 1.1rem; margin: 18px 0 8px;
}
.lesson-body h4 {
    color: var(--gold); font-size: 0.95rem; margin: 14px 0 6px;
}
.lesson-body ul, .lesson-body ol {
    margin: 8px 0 12px 20px;
}
.lesson-body li { margin-bottom: 5px; }
.lesson-body .math-block {
    background: rgba(0,0,0,0.2); border-radius: 10px;
    padding: 12px 16px; margin: 10px 0; font-size: 1.05rem;
    color: #fff; font-weight: 500; text-align: center;
    border: 1px solid rgba(255,255,255,0.06);
}
.lesson-body .math-note {
    background: rgba(255,213,79,0.08); border-left: 3px solid var(--gold);
    padding: 10px 14px; border-radius: 0 8px 8px 0; margin: 12px 0;
    font-size: 0.88rem; color: rgba(255,255,255,0.75);
}
.lesson-body .example-box {
    background: rgba(102,187,106,0.08); border-left: 3px solid var(--green);
    padding: 12px 16px; border-radius: 0 10px 10px 0; margin: 12px 0;
}
.lesson-body .example-box .ex-title {
    font-weight: 600; color: var(--green); margin-bottom: 6px; font-size: 0.9rem;
}

/* Practice button */
.practice-btn {
    display: block; margin: 24px auto 0; padding: 12px 32px;
    background: var(--green); color: #fff; border: none;
    border-radius: 12px; font-family: var(--font-main);
    font-size: 1rem; font-weight: 600; cursor: pointer;
    box-shadow: 0 4px 0 rgba(0,0,0,0.2); transition: all 0.15s;
}
.practice-btn:hover { transform: translateY(-2px); box-shadow: 0 6px 0 rgba(0,0,0,0.2); }
.practice-btn:active { transform: translateY(2px); box-shadow: 0 2px 0 rgba(0,0,0,0.2); }

/* Category overview cards on welcome */
.learn-cats-overview {
    display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 12px; margin-top: 24px; text-align: left;
}
.learn-cat-card {
    background: rgba(255,255,255,0.06); border: 2px solid rgba(255,255,255,0.08);
    border-radius: 14px; padding: 16px; cursor: pointer; transition: all 0.2s;
}
.learn-cat-card:hover { border-color: var(--gold); transform: translateY(-2px); }
.learn-cat-card h3 { color: var(--gold); font-size: 1rem; margin-bottom: 6px; }
.learn-cat-card p { color: rgba(255,255,255,0.5); font-size: 0.78rem; line-height: 1.4; }

/* Responsive */
@media (max-width: 768px) {
    .learn-layout { flex-direction: column; }
    .learn-sidebar { width: 100%; max-height: none; }
    .learn-content { min-height: 300px; }
}
@media (max-width: 480px) {
    .learn-view { padding: 80px 12px 12px; }
    .learn-content { padding: 16px; }
    .lesson-title { font-size: 1.2rem; }
    .learn-cats-overview { grid-template-columns: 1fr; }
}

/* ============================================
   CALCULATOR
   ============================================ */
.calculator {
    position: relative; z-index: 1;
    width: 420px; max-width: 98vw;
    background:
        radial-gradient(circle at 25% 20%, rgba(255,255,255,0.08) 0%, transparent 50%),
        linear-gradient(180deg, var(--body-blue-light) 0%, var(--body-blue) 30%, #2a5da8 100%);
    border-radius: 28px;
    border: 4px solid #2a5da8;
    box-shadow:
        0 12px 40px rgba(0,0,0,0.4),
        inset 0 2px 0 var(--shadow-light),
        inset 0 -3px 0 rgba(0,0,0,0.15);
    padding: 16px 14px 20px;
    animation: calcAppear 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}
@keyframes calcAppear {
    0% { transform: scale(0.85); opacity: 0; }
    100% { transform: scale(1); opacity: 1; }
}

.calc-header { text-align: center; margin-bottom: 10px; }
.brand-top { display: flex; flex-direction: column; align-items: center; gap: 0; }
.brand-name { font-size: 1.4rem; font-weight: 700; color: #fff; letter-spacing: 4px; text-shadow: 0 2px 4px rgba(0,0,0,0.3); }
.model-name { font-size: 0.75rem; font-weight: 400; color: rgba(255,255,255,0.7); letter-spacing: 1px; }
.brand-sub { font-size: 0.65rem; color: rgba(255,255,255,0.5); font-style: italic; }

/* Display */
.display {
    background: var(--display-bg);
    border: 3px solid var(--display-border);
    border-radius: 10px;
    padding: 8px 12px;
    margin-bottom: 12px;
    min-height: 110px;
    box-shadow: inset 0 3px 8px rgba(0,0,0,0.15), 0 2px 0 rgba(255,255,255,0.1);
    position: relative; overflow: hidden;
}
.display::before {
    content: '';
    position: absolute; top: 0; left: 0; right: 0; height: 40%;
    background: linear-gradient(180deg, rgba(255,255,255,0.15) 0%, transparent 100%);
    pointer-events: none; border-radius: 7px 7px 0 0;
}
.indicators { display: flex; gap: 6px; margin-bottom: 4px; flex-wrap: wrap; }
.ind {
    font-size: 0.6rem; font-weight: 600;
    color: rgba(26,26,26,0.25);
    padding: 1px 4px; border-radius: 3px;
    letter-spacing: 0.5px; transition: color 0.2s, background 0.2s;
}
.ind.active { color: var(--display-text); background: rgba(0,0,0,0.08); }

.expression {
    font-size: 1.1rem; font-weight: 500;
    color: var(--display-text);
    min-height: 1.6em;
    word-wrap: break-word; overflow-wrap: break-word;
    line-height: 1.5;
    font-family: var(--font-main);
    position: relative;
}
.expression .cursor {
    display: inline-block; width: 2px; height: 1.1em;
    background: var(--display-text);
    animation: blink 0.8s step-end infinite;
    vertical-align: text-bottom; margin-left: 1px;
}
@keyframes blink { 0%, 100% { opacity: 1; } 50% { opacity: 0; } }

.result {
    font-size: 1.5rem; font-weight: 600;
    color: var(--display-text);
    text-align: right;
    min-height: 1.5em;
    border-top: 1px dashed rgba(0,0,0,0.15);
    margin-top: 4px; padding-top: 4px;
    font-family: var(--font-main);
    overflow-x: auto; white-space: nowrap;
}
.result.error { color: #c62828; font-size: 1rem; }

/* Buttons */
.buttons { display: grid; grid-template-columns: repeat(6, 1fr); gap: 6px; }

.btn {
    font-family: var(--font-main);
    font-size: 0.82rem; font-weight: 500;
    border: 3px solid; border-radius: var(--btn-radius);
    padding: 10px 4px;
    cursor: pointer;
    transition: transform 0.1s cubic-bezier(0.34, 1.56, 0.64, 1), box-shadow 0.1s, background 0.15s;
    box-shadow: 0 4px 0 var(--shadow-dark), 0 5px 8px rgba(0,0,0,0.2);
    position: relative; user-select: none; text-align: center;
    line-height: 1.2; min-height: 44px;
    display: flex; align-items: center; justify-content: center;
}
.btn:hover { transform: translateY(-1px); filter: brightness(1.08); }
.btn:active { transform: translateY(3px); box-shadow: 0 1px 0 var(--shadow-dark); }

.btn-num { background: var(--btn-num-bg); border-color: var(--btn-num-border); color: #222; font-size: 1.1rem; font-weight: 600; }
.btn-num:hover { background: var(--btn-num-hover); }
.btn-op { background: var(--btn-op-bg); border-color: var(--btn-op-border); color: #fff; font-size: 1.1rem; font-weight: 600; text-shadow: 0 1px 2px rgba(0,0,0,0.2); }
.btn-op:hover { background: var(--btn-op-hover); }
.btn-func { background: var(--btn-func-bg); border-color: var(--btn-func-border); color: #fff; text-shadow: 0 1px 2px rgba(0,0,0,0.15); }
.btn-func:hover { background: var(--btn-func-hover); }
.btn-mem { background: var(--btn-mem-bg); border-color: var(--btn-mem-border); color: #fff; text-shadow: 0 1px 2px rgba(0,0,0,0.15); }
.btn-mem:hover { background: var(--btn-mem-hover); }
.btn-eq { background: var(--btn-eq-bg); border-color: var(--btn-eq-border); color: #fff; font-size: 1.2rem; font-weight: 700; text-shadow: 0 1px 2px rgba(0,0,0,0.2); }
.btn-eq:hover { background: var(--btn-eq-hover); }
.btn-ac { background: var(--btn-ac-bg); border-color: var(--btn-ac-border); color: #fff; font-weight: 700; text-shadow: 0 1px 2px rgba(0,0,0,0.2); }
.btn-ac:hover { background: var(--btn-ac-hover); }
.btn-del { background: var(--btn-del-bg); border-color: var(--btn-del-border); color: #fff; font-weight: 600; text-shadow: 0 1px 2px rgba(0,0,0,0.15); }
.btn-shift { background: var(--btn-shift-bg); border-color: var(--btn-shift-border); color: #333; font-weight: 700; }
.btn-shift.active { background: #fdd835; box-shadow: 0 4px 0 var(--shadow-dark), 0 0 12px rgba(253,216,53,0.5); }
.btn-nav { background: var(--btn-nav-bg); border-color: var(--btn-nav-border); color: #333; font-size: 1rem; }
.btn-mode { background: var(--btn-mode-bg); border-color: var(--btn-mode-border); color: #fff; font-weight: 600; text-shadow: 0 1px 2px rgba(0,0,0,0.15); }

/* ============================================
   NAME ENTRY MODAL
   ============================================ */
.name-modal-overlay {
    position: fixed; inset: 0;
    background: rgba(0,0,0,0.7); z-index: 300;
    display: none; justify-content: center; align-items: center;
    padding: 20px;
}
.name-modal-overlay.open { display: flex; }
.name-modal {
    background: #fff; border-radius: 20px; border: 4px solid #333;
    padding: 32px; text-align: center; max-width: 400px; width: 100%;
    box-shadow: 0 16px 60px rgba(0,0,0,0.4);
    animation: panelPop 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}
@keyframes panelPop {
    0% { transform: scale(0.8); opacity: 0; }
    100% { transform: scale(1); opacity: 1; }
}
.name-modal h2 { color: #333; font-size: 1.5rem; margin-bottom: 8px; }
.name-modal p { color: #666; font-size: 0.9rem; margin-bottom: 20px; }
.name-modal-input {
    width: 100%; padding: 12px 16px; font-family: var(--font-main);
    font-size: 1.1rem; border: 3px solid #ccc; border-radius: 12px;
    text-align: center; outline: none; transition: border-color 0.2s;
    margin-bottom: 16px;
}
.name-modal-input:focus { border-color: var(--btn-mode-bg); }
.name-modal-actions { display: flex; gap: 10px; justify-content: center; }
.name-modal-btn {
    padding: 12px 28px; border: 3px solid; border-radius: 12px;
    font-family: var(--font-main); font-size: 1rem; font-weight: 600;
    cursor: pointer; transition: all 0.15s;
}
.name-modal-btn.primary {
    background: var(--green); border-color: #4caf50; color: #fff;
    box-shadow: 0 4px 0 rgba(0,0,0,0.2);
}
.name-modal-btn.primary:hover { transform: translateY(-2px); box-shadow: 0 6px 0 rgba(0,0,0,0.2); }
.name-modal-btn.primary:active { transform: translateY(2px); box-shadow: 0 1px 0 rgba(0,0,0,0.2); }

/* ============================================
   TEST VIEW
   ============================================ */
.test-view { max-width: 900px; margin: 0 auto; padding: 80px 20px 30px; width: 100%; }
.test-header { text-align: center; margin-bottom: 30px; }
.test-header h1 { font-size: 2.2rem; color: #fff; margin-bottom: 6px; }
.test-sub { color: rgba(255,255,255,0.6); font-size: 1rem; }

.test-setup-section {
    background: rgba(255,255,255,0.06); border-radius: 16px;
    border: 2px solid rgba(255,255,255,0.08); padding: 20px 24px;
    margin-bottom: 20px;
}
.test-setup-section h2 { color: #fff; font-size: 1.2rem; margin-bottom: 8px; }
.test-setup-hint { color: rgba(255,255,255,0.5); font-size: 0.85rem; margin-bottom: 16px; }

.test-topic-grid {
    display: flex; flex-wrap: wrap; gap: 8px;
}
.test-topic-cat-label {
    width: 100%; color: var(--gold); font-size: 0.8rem;
    font-weight: 600; margin-top: 8px; margin-bottom: 2px;
    text-transform: uppercase; letter-spacing: 0.5px;
}
.test-topic-cat-label:first-child { margin-top: 0; }
.test-topic-chip {
    padding: 8px 14px; border-radius: 10px;
    background: rgba(255,255,255,0.06); border: 2px solid rgba(255,255,255,0.1);
    color: rgba(255,255,255,0.7); font-family: var(--font-main);
    font-size: 0.82rem; cursor: pointer; transition: all 0.15s;
}
.test-topic-chip:hover { background: rgba(255,255,255,0.1); border-color: rgba(255,255,255,0.2); }
.test-topic-chip.selected {
    background: var(--btn-mode-bg); border-color: var(--btn-mode-border);
    color: #fff;
}

.test-time-options {
    display: flex; flex-wrap: wrap; gap: 10px;
}
.test-time-btn {
    padding: 10px 20px; border-radius: 10px;
    background: rgba(255,255,255,0.06); border: 2px solid rgba(255,255,255,0.1);
    color: rgba(255,255,255,0.7); font-family: var(--font-main);
    font-size: 0.9rem; font-weight: 500; cursor: pointer; transition: all 0.15s;
}
.test-time-btn:hover { background: rgba(255,255,255,0.1); }
.test-time-btn.active {
    background: var(--gold); border-color: var(--gold);
    color: #1a1a2e; font-weight: 600;
}
.test-time-btn.recommended {
    border-color: var(--gold); color: var(--gold);
    position: relative;
}
.test-time-btn.recommended::after {
    content: 'Recommended';
    position: absolute; top: -18px; left: 50%; transform: translateX(-50%);
    font-size: 0.6rem; color: var(--gold); white-space: nowrap;
    font-weight: 600; text-transform: uppercase; letter-spacing: 0.5px;
}
.test-time-btn.recommended.active::after { display: none; }

.test-summary-info { color: rgba(255,255,255,0.7); font-size: 0.9rem; }
.test-summary-info .summary-stat {
    display: flex; justify-content: space-between;
    padding: 6px 0; border-bottom: 1px solid rgba(255,255,255,0.06);
}
.test-summary-info .summary-stat:last-child { border-bottom: none; }
.test-summary-info .summary-label { color: rgba(255,255,255,0.5); }
.test-summary-info .summary-value { color: #fff; font-weight: 600; }

.test-start-btn {
    display: block; width: 100%; max-width: 300px; margin: 20px auto 0;
    padding: 14px 28px; border-radius: 12px;
    background: var(--green); border: 3px solid #4caf50;
    color: #fff; font-family: var(--font-main);
    font-size: 1.1rem; font-weight: 600; cursor: pointer;
    box-shadow: 0 4px 0 rgba(0,0,0,0.2); transition: all 0.15s;
}
.test-start-btn:disabled { opacity: 0.4; cursor: not-allowed; }
.test-start-btn:not(:disabled):hover { transform: translateY(-2px); box-shadow: 0 6px 0 rgba(0,0,0,0.2); }
.test-start-btn:not(:disabled):active { transform: translateY(2px); box-shadow: 0 1px 0 rgba(0,0,0,0.2); }

/* Test Name Screen */
.test-name-card {
    max-width: 400px; margin: 60px auto; text-align: center;
    background: rgba(255,255,255,0.06); border-radius: 20px;
    border: 2px solid rgba(255,255,255,0.1); padding: 40px 30px;
    animation: panelPop 0.3s ease;
}
.test-name-card h2 { color: #fff; font-size: 1.5rem; margin-bottom: 8px; }
.test-name-card p { color: rgba(255,255,255,0.6); font-size: 0.9rem; margin-bottom: 24px; }
.test-name-input {
    width: 100%; padding: 14px 18px; font-family: var(--font-main);
    font-size: 1.1rem; border: 3px solid rgba(255,255,255,0.15);
    border-radius: 12px; background: rgba(255,255,255,0.06);
    color: #fff; outline: none; text-align: center;
    transition: border-color 0.2s; margin-bottom: 20px;
    box-sizing: border-box;
}
.test-name-input:focus { border-color: var(--gold); }
.test-name-input::placeholder { color: rgba(255,255,255,0.3); }
.test-name-actions { display: flex; gap: 12px; justify-content: center; }
.test-name-btn {
    padding: 12px 28px; border: 3px solid; border-radius: 12px;
    font-family: var(--font-main); font-size: 1rem; font-weight: 600;
    cursor: pointer; transition: all 0.15s;
}
.test-name-btn.primary {
    background: var(--green); border-color: #4caf50; color: #fff;
    box-shadow: 0 4px 0 rgba(0,0,0,0.2);
}
.test-name-btn.primary:hover { transform: translateY(-2px); box-shadow: 0 6px 0 rgba(0,0,0,0.2); }
.test-name-btn.secondary {
    background: rgba(255,255,255,0.08); border-color: rgba(255,255,255,0.15);
    color: rgba(255,255,255,0.7);
}
.test-name-btn.secondary:hover { background: rgba(255,255,255,0.12); }

/* Test In Progress */
.test-hud {
    background: rgba(255,255,255,0.06); border-radius: 16px;
    border: 2px solid rgba(255,255,255,0.1); padding: 16px 24px;
    margin-bottom: 20px; text-align: center;
}
.test-hud-timer {
    font-size: 2rem; font-weight: 700; color: #fff;
    font-variant-numeric: tabular-nums; margin-bottom: 6px;
}
.test-hud-timer.warning { color: var(--gold); }
.test-hud-timer.danger { color: var(--red); animation: pulse 1s infinite; }
@keyframes pulse { 0%,100% { opacity: 1; } 50% { opacity: 0.5; } }
.test-hud-progress {
    display: flex; justify-content: space-between;
    color: rgba(255,255,255,0.6); font-size: 0.85rem;
}

.test-question-area {
    background: rgba(255,255,255,0.06); border-radius: 16px;
    border: 2px solid rgba(255,255,255,0.08); padding: 30px 24px;
    margin-bottom: 16px; min-height: 200px;
}
.test-q-number { color: var(--gold); font-size: 0.85rem; font-weight: 600; margin-bottom: 4px; }
.test-q-topic { color: rgba(255,255,255,0.4); font-size: 0.75rem; margin-bottom: 12px; }
.test-q-svg { margin-bottom: 12px; display: flex; justify-content: center; }
.test-q-svg svg { max-width: 280px; }
.test-q-detail { color: rgba(255,255,255,0.5); font-size: 0.85rem; margin-bottom: 8px; font-style: italic; }
.test-q-text { color: #fff; font-size: 1.3rem; font-weight: 500; margin-bottom: 20px; line-height: 1.5; }
.test-q-marks { color: rgba(255,255,255,0.4); font-size: 0.8rem; margin-bottom: 16px; }
.test-q-input {
    width: 100%; padding: 14px 18px; font-family: var(--font-main);
    font-size: 1.1rem; border: 3px solid rgba(255,255,255,0.15);
    border-radius: 12px; background: rgba(255,255,255,0.06);
    color: #fff; outline: none; transition: border-color 0.2s;
    box-sizing: border-box;
}
.test-q-input:focus { border-color: var(--gold); }
.test-q-input::placeholder { color: rgba(255,255,255,0.3); }

.test-nav-btns {
    display: flex; justify-content: space-between; gap: 12px; margin-bottom: 16px;
}
.test-nav-btn {
    padding: 10px 24px; border-radius: 10px;
    background: rgba(255,255,255,0.08); border: 2px solid rgba(255,255,255,0.12);
    color: #fff; font-family: var(--font-main);
    font-size: 0.9rem; font-weight: 500; cursor: pointer; transition: all 0.15s;
}
.test-nav-btn:hover { background: rgba(255,255,255,0.12); }
.test-nav-btn:disabled { opacity: 0.3; cursor: not-allowed; }

.test-question-nav {
    display: flex; flex-wrap: wrap; gap: 6px; justify-content: center;
    margin-bottom: 20px;
}
.test-q-dot {
    width: 32px; height: 32px; border-radius: 8px;
    background: rgba(255,255,255,0.06); border: 2px solid rgba(255,255,255,0.1);
    color: rgba(255,255,255,0.5); font-size: 0.75rem; font-weight: 600;
    display: flex; align-items: center; justify-content: center;
    cursor: pointer; transition: all 0.15s;
}
.test-q-dot:hover { background: rgba(255,255,255,0.1); }
.test-q-dot.current { border-color: var(--gold); color: var(--gold); }
.test-q-dot.answered { background: var(--green); border-color: #4caf50; color: #fff; }

.test-submit-btn {
    display: block; width: 100%; max-width: 300px; margin: 0 auto;
    padding: 14px 28px; border-radius: 12px;
    background: var(--red); border: 3px solid #f44336;
    color: #fff; font-family: var(--font-main);
    font-size: 1rem; font-weight: 600; cursor: pointer;
    box-shadow: 0 4px 0 rgba(0,0,0,0.2); transition: all 0.15s;
}
.test-submit-btn:hover { transform: translateY(-2px); box-shadow: 0 6px 0 rgba(0,0,0,0.2); }

/* Test Results */
.test-results-header { text-align: center; margin-bottom: 30px; }
.test-results-header h1 { color: #fff; font-size: 2rem; margin-bottom: 20px; }
.test-score-circle {
    width: 140px; height: 140px; border-radius: 50%;
    background: rgba(255,255,255,0.06); border: 4px solid var(--gold);
    display: flex; flex-direction: column; align-items: center; justify-content: center;
    margin: 0 auto 16px;
}
.test-score-pct { font-size: 2rem; font-weight: 700; color: #fff; }
.test-score-detail { font-size: 0.85rem; color: rgba(255,255,255,0.6); }
.test-results-name { color: #fff; font-size: 1.1rem; font-weight: 500; margin-bottom: 4px; }
.test-results-date { color: rgba(255,255,255,0.5); font-size: 0.85rem; }

.test-breakdown {
    background: rgba(255,255,255,0.04); border-radius: 16px;
    border: 2px solid rgba(255,255,255,0.06); padding: 20px;
    margin-bottom: 24px;
}
.test-breakdown-topic {
    margin-bottom: 16px;
}
.test-breakdown-topic h3 {
    color: var(--gold); font-size: 0.9rem; margin-bottom: 8px;
    padding-bottom: 6px; border-bottom: 1px solid rgba(255,255,255,0.08);
}
.test-breakdown-q {
    display: flex; justify-content: space-between; align-items: center;
    padding: 6px 0; font-size: 0.85rem;
}
.test-breakdown-q .q-result { font-weight: 600; }
.test-breakdown-q .q-result.correct { color: var(--green); }
.test-breakdown-q .q-result.wrong { color: var(--red); }
.test-breakdown-q .q-result.unanswered { color: rgba(255,255,255,0.3); }

.test-download-btn {
    display: block; width: 100%; max-width: 300px; margin: 0 auto 12px;
    padding: 14px 28px; border-radius: 12px;
    background: var(--btn-func-bg); border: 3px solid var(--btn-func-border);
    color: #fff; font-family: var(--font-main);
    font-size: 1rem; font-weight: 600; cursor: pointer;
    box-shadow: 0 4px 0 rgba(0,0,0,0.2); transition: all 0.15s;
}
.test-download-btn:hover { transform: translateY(-2px); box-shadow: 0 6px 0 rgba(0,0,0,0.2); }
.test-new-btn {
    display: block; width: 100%; max-width: 300px; margin: 0 auto;
    padding: 12px 24px; border-radius: 12px;
    background: rgba(255,255,255,0.08); border: 2px solid rgba(255,255,255,0.12);
    color: rgba(255,255,255,0.7); font-family: var(--font-main);
    font-size: 0.95rem; font-weight: 500; cursor: pointer; transition: all 0.15s;
}
.test-new-btn:hover { background: rgba(255,255,255,0.12); }

/* Session download button */
.session-download-btn {
    position: fixed; bottom: 20px; right: 20px;
    padding: 12px 20px;
    background: var(--btn-func-bg); border: 3px solid var(--btn-func-border);
    color: #fff; border-radius: 12px;
    font-family: var(--font-main); font-size: 0.85rem; font-weight: 600;
    cursor: pointer; box-shadow: 0 4px 12px rgba(0,0,0,0.3);
    transition: all 0.2s; z-index: 100;
    display: none;
}
.session-download-btn.visible { display: block; }
.session-download-btn:hover { transform: translateY(-2px); box-shadow: 0 6px 16px rgba(0,0,0,0.4); }
.session-download-btn:active { transform: translateY(1px); box-shadow: 0 2px 8px rgba(0,0,0,0.3); }

/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 520px) {
    .menu-hero h1 { font-size: 2rem; }
    .question-text { font-size: 1.8rem; }
    .opt-btn { font-size: 0.78rem; padding: 7px 12px; }
    .score-circle { width: 100px; height: 100px; }
    .score-pct { font-size: 1.6rem; }
    .table-picker { grid-template-columns: repeat(5, 1fr); gap: 5px; }
    .tp-btn { font-size: 0.82rem; padding: 8px 4px; }
    .carousel-tab { font-size: 0.85rem; padding: 10px 12px; }
    .test-view { padding: 80px 12px 12px; }
    .test-header h1 { font-size: 1.8rem; }
    .test-setup-section { padding: 16px; }
    .test-time-options { gap: 8px; }
    .test-time-btn { padding: 8px 14px; font-size: 0.82rem; }
    .test-q-text { font-size: 1.1rem; }
    .test-hud-timer { font-size: 1.6rem; }
    .test-score-circle { width: 120px; height: 120px; }
    .test-score-pct { font-size: 1.6rem; }
    .session-download-btn { font-size: 0.75rem; padding: 10px 16px; bottom: 12px; right: 12px; }
}

@media (max-width: 460px) {
    .calculator { padding: 10px 8px 14px; border-radius: 20px; }
    .btn { font-size: 0.7rem; padding: 8px 2px; min-height: 38px; border-width: 2px; border-radius: 8px; }
    .btn-num { font-size: 0.95rem; }
    .buttons { gap: 4px; }
    .display { min-height: 90px; padding: 6px 8px; }
    .expression { font-size: 0.95rem; }
    .result { font-size: 1.2rem; }
    .hud-item { padding: 6px 12px; min-width: 70px; }
    .hud-value { font-size: 1.1rem; }
}

@media (max-width: 360px) {
    .btn { font-size: 0.62rem; padding: 6px 1px; min-height: 34px; }
    .buttons { gap: 3px; }
    .option-row { gap: 5px; }
    .opt-btn { font-size: 0.72rem; padding: 6px 10px; }
    .table-picker { grid-template-columns: repeat(4, 1fr); }
    .tp-btn { font-size: 0.75rem; padding: 7px 2px; }
}