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

:root {
    --bg-primary: #000;
    --bg-secondary: #0a0a0a;
    --bg-tertiary: #111;
    --border-primary: #1a1a1a;
    --border-secondary: #333;
    --text-primary: #fff;
    --text-secondary: #999;
    --text-tertiary: #666;
    --accent-blue: #3b82f6;
    --accent-purple: #a855f7;
    --accent-green: #10b981;
    --accent-yellow: #f59e0b;
    --accent-red: #ef4444;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Arial, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

.fade-in {
    animation: fadeIn 0.6s ease-out;
}

.pulse {
    animation: pulse 2s ease-in-out infinite;
}

::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
    background: var(--border-secondary);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #444;
}

.icon {
    width: 20px;
    height: 20px;
}

.header {
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-primary);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
}

.header-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo-container {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo-icon {
    background: linear-gradient(135deg, #fff 0%, #e0e0e0 100%);
    padding: 0.625rem;
    border-radius: 0.75rem;
    box-shadow: 0 4px 12px rgba(255, 255, 255, 0.1);
}

.logo-icon .icon {
    width: 24px;
    height: 24px;
    color: #000;
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: -0.05em;
    background: linear-gradient(135deg, #fff 0%, #999 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.logo-subtitle {
    font-size: 0.7rem;
    color: var(--text-tertiary);
    letter-spacing: 0.05em;
}

.nav {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.875rem;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.625rem 1rem;
    border-radius: 0.5rem;
}

.nav-link:hover {
    color: var(--text-primary);
    background: var(--bg-tertiary);
}

.nav-link.active {
    color: var(--text-primary);
}

.settings-btn {
    background: transparent;
    border: 1px solid var(--border-secondary);
    color: var(--text-secondary);
    padding: 0.625rem;
    border-radius: 0.5rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.settings-btn:hover {
    background: var(--bg-tertiary);
    border-color: var(--border-secondary);
    color: var(--text-primary);
    transform: rotate(90deg);
}

.settings-panel {
    position: fixed;
    top: 0;
    right: -400px;
    width: 400px;
    height: 100vh;
    background: var(--bg-secondary);
    border-left: 1px solid var(--border-primary);
    z-index: 1000;
    transition: right 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    overflow-y: auto;
}

.settings-panel.active {
    right: 0;
    box-shadow: -10px 0 40px rgba(0, 0, 0, 0.5);
}

.settings-header {
    padding: 2rem;
    border-bottom: 1px solid var(--border-primary);
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    background: var(--bg-secondary);
    z-index: 10;
}

.settings-header h2 {
    font-size: 1.5rem;
    font-weight: 600;
}

.close-settings {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 0.5rem;
    transition: all 0.2s;
}

.close-settings:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.setting-label {
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
}

.setting-name {
    font-size: 1rem;
    font-weight: 500;
}

.toggle-slider {
    width: 48px;
    height: 26px;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-secondary);
    border-radius: 13px;
    position: relative;
    transition: all 0.3s;
}

.toggle-slider::after {
    content: '';
    position: absolute;
    width: 18px;
    height: 18px;
    background: var(--text-secondary);
    border-radius: 50%;
    top: 3px;
    left: 3px;
    transition: all 0.3s;
}

input[type="checkbox"]:checked + .toggle-slider {
    background: var(--accent-blue);
    border-color: var(--accent-blue);
}

input[type="checkbox"]:checked + .toggle-slider::after {
    background: white;
    transform: translateX(22px);
}

.setting-section-title {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.radio-group {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.radio-label {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    cursor: pointer;
    padding: 0.75rem;
    border-radius: 0.5rem;
    transition: background 0.2s;
}

.radio-label:hover {
    background: var(--bg-tertiary);
}

.radio-custom {
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-secondary);
    border-radius: 50%;
    position: relative;
    transition: all 0.2s;
}

input[type="radio"]:checked + .radio-custom {
    border-color: var(--accent-blue);
}

input[type="radio"]:checked + .radio-custom::after {
    content: '';
    position: absolute;
    width: 10px;
    height: 10px;
    background: var(--accent-blue);
    border-radius: 50%;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.slider-container input[type="range"] {
    width: 100%;
    height: 6px;
    background: var(--bg-tertiary);
    border-radius: 3px;
    outline: none;
    -webkit-appearance: none;
}

.slider-container input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 18px;
    height: 18px;
    background: var(--accent-blue);
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.2s;
}

.slider-container input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

.slider-value {
    text-align: center;
    margin-top: 0.75rem;
    font-weight: 600;
    color: var(--accent-blue);
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 3rem 2rem;
    position: relative;
}

.hero {
    text-align: center;
    margin-bottom: 4rem;
}

.badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: linear-gradient(135deg, var(--bg-tertiary) 0%, var(--bg-secondary) 100%);
    border: 1px solid var(--border-secondary);
    padding: 0.625rem 1.25rem;
    border-radius: 9999px;
    margin-bottom: 2rem;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.badge span {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.hero-title {
    font-size: 4rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    background: linear-gradient(135deg, #fff 0%, #666 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    line-height: 1.1;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    max-width: 900px;
    margin: 0 auto;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 1.5rem;
    margin-bottom: 5rem;
}

.stat-card {
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
    border: 1px solid var(--border-primary);
    border-radius: 1.25rem;
    padding: 2rem;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.stat-card:hover {
    transform: translateY(-8px);
    border-color: var(--border-secondary);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
}

.stat-icon {
    width: 40px;
    height: 40px;
    color: var(--text-tertiary);
    margin-bottom: 1.25rem;
    transition: all 0.3s;
}

.stat-card:hover .stat-icon {
    color: var(--accent-blue);
    transform: scale(1.1);
}

.stat-value {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, #fff 0%, #999 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-tertiary);
    font-weight: 500;
}

.section-title {
    font-size: 2.25rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
    text-align: center;
}

.section-subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
    text-align: center;
    margin-bottom: 2rem;
}

.filter-input {
    display: block;
    width: 100%;
    max-width: 420px;
    margin: 1.5rem auto;
    padding: 0.9rem 1.25rem;
    font-size: 1rem;
    background: #111;
    border: 1px solid #333;
    border-radius: 0.75rem;
    color: white;
}

.filter-input:focus {
    outline: none;
    border-color: var(--accent-blue);
    box-shadow: 0 0 0 3px rgba(59,130,246,0.2);
}

.grade-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(170px, 1fr));
    gap: 1.5rem;
}

.grade-card {
    background: linear-gradient(145deg, #111 0%, #0a0a0a 100%);
    border: 1px solid #222;
    border-radius: 1.25rem;
    padding: 1.75rem 1.25rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
    position: relative;
    overflow: hidden;
}

.grade-card::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at 30% 20%, rgba(59,130,246,0.12) 0%, transparent 60%);
    opacity: 0;
    transition: opacity 0.5s;
}

.grade-card:hover::before {
    opacity: 1;
}

.grade-card:hover {
    transform: translateY(-8px) scale(1.04);
    border-color: #3b82f6;
    box-shadow: 0 20px 40px rgba(59,130,246,0.18);
}

.grade-svg {
    width: 56px;
    height: 56px;
    margin-bottom: 1.25rem;
    stroke: #60a5fa;
    stroke-width: 2.2;
    stroke-linecap: round;
    stroke-linejoin: round;
    transition: all 0.45s cubic-bezier(0.34, 1.56, 0.64, 1);
    filter: drop-shadow(0 2px 4px rgba(59, 130, 246, 0.25));
}

.grade-card:hover .grade-svg {
    stroke: #c084fc;
    transform: scale(1.22) rotate(10deg);
    filter: drop-shadow(0 6px 12px rgba(168, 85, 247, 0.45));
}

.grade-name {
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
}

.grade-arrow {
    width: 20px;
    height: 20px;
    color: var(--text-tertiary);
    margin: 0.5rem auto 0;
    transition: all 0.3s;
}

.grade-card:hover .grade-arrow {
    color: var(--accent-blue);
    transform: translateX(4px);
}

.subjects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.5rem;
}

.subject-card {
    background: linear-gradient(135deg, var(--bg-tertiary) 0%, var(--bg-secondary) 100%);
    border: 1px solid var(--border-primary);
    border-radius: 1.25rem;
    padding: 2rem;
    cursor: pointer;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
}

.subject-card:hover {
    transform: translateY(-8px);
    border-color: var(--accent-blue);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
}

.subject-icon-wrapper {
    padding: 1rem;
    border-radius: 1rem;
    width: fit-content;
    margin-bottom: 1.5rem;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
}

.subject-icon-wrapper.math { background: linear-gradient(135deg, #3b82f6 0%, #1d4ed8 100%); }
.subject-icon-wrapper.ela  { background: linear-gradient(135deg, #a855f7 0%, #7e22ce 100%); }
.subject-icon-wrapper.science { background: linear-gradient(135deg, #10b981 0%, #059669 100%); }
.subject-icon-wrapper.social { background: linear-gradient(135deg, #f59e0b 0%, #d97706 100%); }

.subject-icon-wrapper .icon {
    width: 28px;
    height: 28px;
    color: #fff;
}

.subject-card h3 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.subject-desc {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    line-height: 1.7;
}

.subject-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.topic-count {
    font-size: 0.875rem;
    color: var(--text-tertiary);
    font-weight: 500;
}

.chevron {
    width: 24px;
    height: 24px;
    color: var(--text-tertiary);
    transition: all 0.3s;
}

.subject-card:hover .chevron {
    color: var(--accent-blue);
    transform: translateX(4px);
}

.back-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-size: 1rem;
    margin-bottom: 2rem;
    cursor: pointer;
    padding: 0.75rem 1rem;
    border-radius: 0.5rem;
    transition: all 0.3s;
}

.back-btn:hover {
    color: var(--text-primary);
    background: var(--bg-tertiary);
}

.topic-header {
    display: flex;
    align-items: center;
    gap: 2rem;
    margin-bottom: 3rem;
    padding: 2rem;
    background: linear-gradient(135deg, var(--bg-tertiary) 0%, var(--bg-secondary) 100%);
    border: 1px solid var(--border-primary);
    border-radius: 1.5rem;
}

.topic-icon-large {
    padding: 1.25rem;
    border-radius: 1.25rem;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
}

.topic-icon-large .icon {
    width: 32px;
    height: 32px;
    color: #fff;
}

.topics-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.topic-item {
    background: linear-gradient(135deg, var(--bg-tertiary) 0%, var(--bg-secondary) 100%);
    border: 1px solid var(--border-primary);
    border-radius: 1rem;
    padding: 1.5rem 1.75rem;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.topic-item:hover {
    transform: translateX(8px);
    border-color: var(--accent-blue);
    box-shadow: 0 8px 16px rgba(59, 130, 246, 0.2);
}

.topic-item-content {
    display: flex;
    align-items: center;
    gap: 1.25rem;
}

.topic-number {
    background: var(--bg-primary);
    border: 1px solid var(--border-secondary);
    border-radius: 0.75rem;
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    font-weight: 700;
    color: var(--text-secondary);
    transition: all 0.3s;
}

.topic-item:hover .topic-number {
    background: var(--accent-blue);
    color: white;
    border-color: var(--accent-blue);
}

.practice-hud {
    background: linear-gradient(135deg, #111 0%, #0a0a0a 100%);
    border-radius: 1.25rem;
    padding: 1.5rem 2rem;
    margin-bottom: 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border: 1px solid #222;
}

.hud-left {
    display: flex;
    gap: 3rem;
}

.hud-item {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.hud-label {
    font-size: 0.75rem;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 600;
}

.hud-value {
    font-size: 1.5rem;
    font-weight: 700;
}

.hud-value-small {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.hud-right {
    display: flex;
    gap: 1.25rem;
    flex-wrap: wrap;
}

.hud-stat {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0.75rem 1.25rem;
    background: var(--bg-primary);
    border: 1px solid var(--border-secondary);
    border-radius: 0.75rem;
}

.hud-stat.streak {
    border-color: rgba(245,158,11,0.3);
    background: rgba(245,158,11,0.05);
}

.hud-stat.points {
    background: rgba(245,158,11,0.08);
    border-color: rgba(245,158,11,0.3);
}

.hud-stat-icon {
    width: 36px;
    height: 36px;
    border-radius: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.hud-stat-icon.accuracy {
    background: rgba(59,130,246,0.1);
}

.hud-stat-icon.fire {
    background: rgba(245,158,11,0.1);
}

.hud-stat-value {
    font-size: 1.5rem;
    font-weight: 700;
}

#points-display {
    color: #fbbf24;
}

.progress-container {
    margin-bottom: 2.5rem;
}

.progress-bar-wrapper {
    width: 100%;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-primary);
    border-radius: 9999px;
    height: 12px;
    overflow: hidden;
}

.progress-bar {
    background: linear-gradient(90deg, var(--accent-blue) 0%, var(--accent-purple) 100%);
    height: 100%;
    width: 0%;
    transition: width 0.6s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 0 12px rgba(59, 130, 246, 0.5);
}

.progress-label {
    text-align: center;
    margin-top: 0.75rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 600;
}

.question-card {
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
    border: 1px solid var(--border-primary);
    border-radius: 1.5rem;
    padding: 3rem;
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.4);
}

.question-number {
    display: inline-block;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-secondary);
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    text-transform: uppercase;
}

.question-text {
    font-size: 1.75rem;
    margin-bottom: 2.5rem;
    line-height: 1.6;
    font-weight: 500;
}

.options-container {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 2rem;
}

.option-btn {
    background: var(--bg-tertiary);
    border: 2px solid var(--border-primary);
    color: var(--text-primary);
    padding: 1.5rem 1.75rem;
    border-radius: 1rem;
    cursor: pointer;
    font-size: 1.05rem;
    text-align: left;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative;
    overflow: hidden;
}

.option-btn:hover:not(:disabled) {
    background: var(--bg-secondary);
    border-color: var(--accent-blue);
    transform: translateX(8px);
    box-shadow: 0 8px 16px rgba(59, 130, 246, 0.2);
}

.option-btn.selected {
    background: rgba(59, 130, 246, 0.1);
    border-color: var(--accent-blue);
}

.option-btn.correct {
    background: rgba(16,185,129,0.12);
    border-color: #10b981;
    color: #6ee7b7;
}

.option-btn.incorrect {
    background: rgba(239,68,68,0.12);
    border-color: #ef4444;
    color: #fca5a5;
}

.option-btn:disabled {
    cursor: default;
}

.submit-btn {
    width: 100%;
    background: linear-gradient(135deg, #fff 0%, #e0e0e0 100%);
    color: #000;
    border: none;
    padding: 1.25rem 2rem;
    border-radius: 1rem;
    cursor: pointer;
    font-size: 1.1rem;
    font-weight: 700;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    box-shadow: 0 8px 16px rgba(255, 255, 255, 0.1);
}

.submit-btn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 12px 24px rgba(255, 255, 255, 0.2);
}

.submit-btn:disabled {
    background: var(--bg-tertiary);
    color: var(--text-tertiary);
    cursor: not-allowed;
}

.feedback {
    margin-top: 1.5rem;
    padding: 1.5rem;
    border-radius: 1rem;
    border: 2px solid;
    font-size: 1.05rem;
    font-weight: 500;
    display: none;
}

.feedback.show {
    display: block;
}

.feedback.correct {
    background: rgba(16,185,129,0.1);
    border-color: #10b981;
    color: #6ee7b7;
}

.feedback.incorrect {
    background: rgba(239,68,68,0.1);
    border-color: #ef4444;
    color: #fca5a5;
}

.results-card {
    text-align: center;
    background: linear-gradient(135deg, var(--bg-tertiary) 0%, var(--bg-secondary) 100%);
    border: 1px solid var(--border-primary);
    border-radius: 2rem;
    padding: 4rem 3rem;
    box-shadow: 0 20px 48px rgba(0, 0, 0, 0.5);
}

.results-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
}

.final-score {
    font-size: 5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, #fff 0%, #999 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.results-text {
    color: var(--text-secondary);
    margin-bottom: 3rem;
    font-size: 1.1rem;
}

.results-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    margin-bottom: 3rem;
    padding: 2rem;
    background: var(--bg-primary);
    border: 1px solid var(--border-primary);
    border-radius: 1rem;
}

.result-stat {
    text-align: center;
}

.result-stat-value {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.result-stat-label {
    font-size: 0.875rem;
    color: var(--text-tertiary);
    text-transform: uppercase;
}

.results-actions {
    display: flex;
    gap: 1rem;
}

.continue-btn {
    flex: 1;
    border: none;
    padding: 1.25rem 2rem;
    border-radius: 1rem;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 700;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
}

.continue-btn.primary {
    background: linear-gradient(90deg, #60a5fa, #a78bfa);
    color: white;
}

.continue-btn.secondary {
    background: var(--bg-primary);
    color: var(--text-primary);
    border: 1px solid var(--border-secondary);
}

.continue-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.3);
}

.continue-btn.primary:hover {
    box-shadow: 0 12px 24px rgba(96,165,250,0.4);
}

@media (max-width: 1024px) {
    .subjects-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .nav {
        display: none;
    }
    .hero-title {
        font-size: 2.5rem;
    }
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .grade-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .practice-hud {
        flex-direction: column;
        gap: 1.5rem;
    }
    .hud-left, .hud-right {
        width: 100%;
        justify-content: space-between;
    }
    .results-stats {
        grid-template-columns: 1fr;
    }
    .results-actions {
        flex-direction: column;
    }
    .settings-panel {
        width: 100%;
        right: -100%;
    }
}

@media (max-width: 640px) {
  .grade-grid {
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  }
  .grade-svg {
    width: 44px;
    height: 44px;
  }
}
.grade-card:nth-child(-n+5) .grade-svg {
    stroke: #f59e0b;
}
.grade-card:nth-child(-n+5):hover .grade-svg {
    stroke: #fbbf24;
    filter: drop-shadow(0 6px 12px rgba(245, 158, 11, 0.5));
}
.grade-card:nth-child(n+6):nth-child(-n+9) .grade-svg {
    stroke: #34d399;
}

.grade-card:nth-child(n+6):nth-child(-n+9):hover .grade-svg {
    stroke: #6ee7b7;
}
.grade-card:nth-child(n+10) .grade-svg {
    stroke: #a855f7;
}
.grade-card:nth-child(n+10):hover .grade-svg {
    stroke: #c084fc;
}
.grade-svg {
    width: 64px !important;
    height: 64px !important;
    margin-bottom: 1.25rem;
    stroke: #60a5fa;
    stroke-width: 2.5;
    stroke-linecap: round;
    stroke-linejoin: round;
    transition: all 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.grade-card:hover .grade-svg {
    transform: scale(1.25) rotate(12deg);
    stroke: #c084fc;
}
.option-btn.correct {
    background: rgba(16, 185, 129, 0.18) !important;
    border-color: #10b981 !important;
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(16,185,129,0.3);
}

.option-btn.incorrect {
    background: rgba(239, 68, 68, 0.18) !important;
    border-color: #ef4444 !important;
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(239,68,68,0.3);
}
.submit-btn .btn-icon, 
.continue-btn .btn-icon {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

.submit-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
}
.btn-icon {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

.results-icon {
    width: 64px;
    height: 64px;
    color: var(--accent-green);
    margin-bottom: 1.5rem;
}

.results-icon-wrapper {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 1rem;
}
.settings-content {
    padding: 2rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.setting-group {
    background: var(--bg-tertiary);
    padding: 1rem;
    border-radius: 0.75rem;
    border: 1px solid var(--border-primary);
}

.setting-label input[type="checkbox"] {
    opacity: 0;
    width: 0;
    height: 0;
    position: absolute;
}

.setting-section {
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border-primary);
}

@media (max-width: 400px) {
    .settings-panel {
        width: 100%;
    }
}
.close-settings {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.close-settings svg {
    width: 24px;
    height: 24px;
}
.settings-content {
    padding: 2rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.setting-group {
    background: var(--bg-tertiary);
    padding: 1.25rem;
    border-radius: 0.8rem;
    border: 1px solid var(--border-primary);
}

.setting-label input[type="checkbox"] {
    position: absolute;
    opacity: 0;
    cursor: pointer;
    height: 0;
    width: 0;
}

.setting-label {
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    width: 100%;
}