/* ===== CSS Variables & Reset ===== */
:root {
    /* Color Palette */
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --secondary-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --success-gradient: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --error-gradient: linear-gradient(135deg, #fa709a 0%, #fee140 100%);

    --primary-color: #667eea;
    --primary-dark: #5568d3;
    --secondary-color: #764ba2;
    --success-color: #00f2fe;
    --error-color: #f5576c;

    --bg-primary: #0f0f23;
    --bg-secondary: #1a1a2e;
    --bg-card: rgba(26, 26, 46, 0.8);
    --bg-glass: rgba(255, 255, 255, 0.05);

    --text-primary: #ffffff;
    --text-secondary: #a0a0c0;
    --text-muted: #6b6b8c;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;

    /* Border Radius */
    --radius-sm: 0.5rem;
    --radius-md: 1rem;
    --radius-lg: 1.5rem;
    --radius-xl: 2rem;

    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.3);
    --shadow-glow: 0 0 40px rgba(102, 126, 234, 0.3);

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    overflow-x: hidden;
    line-height: 1.6;
}

/* ===== Background Animation ===== */
.background-gradient {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at 20% 50%, rgba(102, 126, 234, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(118, 75, 162, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 40% 20%, rgba(0, 242, 254, 0.1) 0%, transparent 50%);
    z-index: -1;
    animation: gradientShift 15s ease infinite;
}

@keyframes gradientShift {

    0%,
    100% {
        opacity: 1;
        transform: scale(1);
    }

    50% {
        opacity: 0.8;
        transform: scale(1.1);
    }
}

/* ===== Container ===== */
.container {
    max-width: 900px;
    margin: 0 auto;
    padding: var(--spacing-lg);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* ===== Screen Management ===== */
.screen {
    display: none;
    width: 100%;
    animation: fadeIn 0.5s ease;
}

.screen.active {
    display: block;
}

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

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ===== Start Screen ===== */
.hero-section {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.icon-wrapper {
    display: inline-flex;
    padding: var(--spacing-md);
    background: var(--primary-gradient);
    border-radius: var(--radius-xl);
    margin-bottom: var(--spacing-md);
    box-shadow: var(--shadow-glow);
    animation: float 3s ease-in-out infinite;
}

@keyframes float {

    0%,
    100% {
        transform: translateY(0px);
    }

    50% {
        transform: translateY(-10px);
    }
}

.hero-icon {
    width: 64px;
    height: 64px;
    color: white;
}

.title {
    font-size: 3rem;
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-sm);
    letter-spacing: -0.02em;
}

.subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    font-weight: 400;
}

.section-title {
    font-size: 1.5rem;
    font-weight: 600;
    text-align: center;
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
}

/* ===== Difficulty Selector ===== */
.difficulty-selector {
    margin-bottom: var(--spacing-xl);
}

.difficulty-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
}

.difficulty-btn {
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border: 2px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    cursor: pointer;
    transition: all var(--transition-normal);
    text-align: center;
    position: relative;
    overflow: hidden;
}

.difficulty-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--primary-gradient);
    opacity: 0;
    transition: opacity var(--transition-normal);
    z-index: -1;
}

.difficulty-btn:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.difficulty-btn:hover::before {
    opacity: 0.1;
}

.difficulty-btn:active {
    transform: translateY(-2px);
}

.difficulty-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
    animation: bounce 2s ease-in-out infinite;
}

@keyframes bounce {

    0%,
    100% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.1);
    }
}

.difficulty-name {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

.difficulty-desc {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* ===== Stats Preview ===== */
.stats-preview {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
}

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

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-xs);
}

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

/* ===== Quiz Screen ===== */
.quiz-header {
    margin-bottom: var(--spacing-xl);
}

.progress-section {
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
}

.progress-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-sm);
    font-size: 0.875rem;
    font-weight: 500;
}

.progress-text,
.score-text {
    color: var(--text-secondary);
}

.progress-text span,
.score-text span {
    color: var(--text-primary);
    font-weight: 600;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 999px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--primary-gradient);
    border-radius: 999px;
    transition: width var(--transition-normal);
    box-shadow: 0 0 10px rgba(102, 126, 234, 0.5);
}

/* ===== Question Card ===== */
.question-card {
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
}

.verb-display {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.verb-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
}

.verb-word {
    font-size: 3rem;
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {

    0%,
    100% {
        opacity: 1;
    }

    50% {
        opacity: 0.8;
    }
}

.form-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.input-group {
    position: relative;
}

.input-label {
    display: block;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xs);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.verb-input {
    width: 100%;
    padding: var(--spacing-md);
    background: rgba(255, 255, 255, 0.05);
    border: 2px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 1.125rem;
    font-weight: 500;
    transition: all var(--transition-normal);
    font-family: inherit;
}

.verb-input:focus {
    outline: none;
    border-color: var(--primary-color);
    background: rgba(255, 255, 255, 0.08);
    box-shadow: 0 0 0 4px rgba(102, 126, 234, 0.1);
}

.verb-input::placeholder {
    color: var(--text-muted);
}

.verb-input.correct {
    border-color: var(--success-color);
    background: rgba(0, 242, 254, 0.1);
}

.verb-input.incorrect {
    border-color: var(--error-color);
    background: rgba(245, 87, 108, 0.1);
    animation: shake 0.5s ease;
}

@keyframes shake {

    0%,
    100% {
        transform: translateX(0);
    }

    25% {
        transform: translateX(-10px);
    }

    75% {
        transform: translateX(10px);
    }
}

.input-feedback {
    margin-top: var(--spacing-xs);
    font-size: 0.875rem;
    font-weight: 500;
    min-height: 1.25rem;
}

.input-feedback.correct {
    color: var(--success-color);
}

.input-feedback.incorrect {
    color: var(--error-color);
}

.input-example {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xs);
    font-style: italic;
    line-height: 1.4;
}

.input-hint {
    margin-top: var(--spacing-xs);
    font-size: 0.85rem;
    color: var(--primary-color);
    font-weight: 500;
    min-height: 1.25rem;
    opacity: 0.8;
}

/* ===== Buttons ===== */
.submit-btn,
.next-btn {
    width: 100%;
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--primary-gradient);
    border: none;
    border-radius: var(--radius-md);
    color: white;
    font-size: 1.125rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-normal);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    box-shadow: var(--shadow-md);
    font-family: inherit;
}

.submit-btn:hover,
.next-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.submit-btn:active,
.next-btn:active {
    transform: translateY(0);
}

.submit-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

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

/* ===== Feedback Card ===== */
.feedback-card {
    margin-top: var(--spacing-lg);
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    animation: slideUp 0.3s ease;
}

.feedback-card.hidden {
    display: none;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.feedback-content {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.feedback-icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-md);
    animation: scaleIn 0.5s ease;
}

@keyframes scaleIn {
    from {
        transform: scale(0);
    }

    to {
        transform: scale(1);
    }
}

.feedback-message {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.feedback-message.correct {
    color: var(--success-color);
}

.feedback-message.incorrect {
    color: var(--error-color);
}

.correct-answer {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-top: var(--spacing-sm);
}

.correct-answer strong {
    color: var(--text-primary);
}

/* ===== Results Screen ===== */
.results-content {
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    text-align: center;
}

.results-icon {
    font-size: 5rem;
    margin-bottom: var(--spacing-md);
    animation: scaleIn 0.5s ease;
}

.results-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xl);
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.results-score {
    display: flex;
    justify-content: center;
    margin-bottom: var(--spacing-xl);
}

.score-circle {
    position: relative;
    width: 200px;
    height: 200px;
}

.score-ring {
    width: 100%;
    height: 100%;
    transform: rotate(-90deg);
}

.score-ring-bg {
    fill: none;
    stroke: rgba(255, 255, 255, 0.1);
    stroke-width: 8;
}

.score-ring-fill {
    fill: none;
    stroke: url(#scoreGradient);
    stroke-width: 8;
    stroke-linecap: round;
    stroke-dasharray: 339.292;
    stroke-dashoffset: 339.292;
    transition: stroke-dashoffset 1s ease;
}

.score-percentage {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 3rem;
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.results-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
    padding: var(--spacing-lg);
    background: rgba(255, 255, 255, 0.03);
    border-radius: var(--radius-md);
}

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

.result-stat-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xs);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.result-stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
}

.result-stat-value.correct {
    color: var(--success-color);
}

.result-stat-value.incorrect {
    color: var(--error-color);
}

.results-actions {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-md);
}

.action-btn {
    padding: var(--spacing-md) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-normal);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    font-family: inherit;
}

.action-btn.primary {
    background: var(--primary-gradient);
    color: white;
    box-shadow: var(--shadow-md);
}

.action-btn.primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.action-btn.secondary {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
    border: 2px solid rgba(255, 255, 255, 0.1);
}

.action-btn.secondary:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

.action-btn:active {
    transform: translateY(0);
}

/* ===== Settings Section ===== */
.settings-section {
    margin-bottom: var(--spacing-xl);
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
}

.settings-grid {
    display: grid;
    /* grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); */
    gap: var(--spacing-md);
    align-items: center;
}

.setting-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--text-secondary);
    font-size: 0.95rem;
    transition: opacity var(--transition-normal);
}

.setting-select {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    padding: 0.25rem 0.5rem;
    cursor: pointer;
}

/* ===== Flashcard Study Mode ===== */
.study-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-xl);
}

.back-btn {
    background: transparent;
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: var(--text-secondary);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-md);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    transition: all var(--transition-normal);
}

.back-btn svg {
    width: 18px;
    height: 18px;
}

.back-btn:hover {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
}

.flashcard-container {
    perspective: 1000px;
    width: 100%;
    max-width: 500px;
    margin: 0 auto var(--spacing-xl);
    aspect-ratio: 4/3;
}

.flashcard {
    width: 100%;
    height: 100%;
    position: relative;
    cursor: pointer;
    transition: transform 0.6s;
    transform-style: preserve-3d;
}

.flashcard.flipped {
    transform: rotateY(180deg);
}

.flashcard-front,
.flashcard-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: var(--bg-card);
    border: 2px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-lg);
}

.flashcard-back {
    transform: rotateY(180deg);
    background: linear-gradient(135deg, rgba(26, 26, 46, 0.9) 0%, rgba(46, 46, 86, 0.9) 100%);
}

.card-label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--text-muted);
    margin-bottom: var(--spacing-md);
}

.card-word {
    font-size: 4rem;
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

.card-hint {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-top: auto;
}

.forms-display {
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.form-item {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.form-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    margin-bottom: 4px;
}

.form-word {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
}

.form-divider {
    height: 1px;
    background: rgba(255, 255, 255, 0.1);
    width: 100%;
}

.study-example {
    margin-bottom: var(--spacing-xl);
}

.example-box {
    background: var(--bg-glass);
    border-left: 4px solid var(--primary-color);
    padding: var(--spacing-md);
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.example-label {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-bottom: var(--spacing-xs);
}

.example-text {
    font-size: 1rem;
    margin-bottom: var(--spacing-xs);
}

.study-controls {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
}

.nav-btn {
    background: var(--bg-card);
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: var(--text-primary);
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--radius-md);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1rem;
    font-weight: 600;
    transition: all var(--transition-normal);
}

.nav-btn:hover {
    border-color: var(--primary-color);
    background: rgba(255, 255, 255, 0.05);
}

.nav-btn svg {
    width: 20px;
    height: 20px;
}

/* ===== Timer UI ===== */
.timer-container {
    margin-top: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    transition: all 0.3s ease;
}

.timer-container.hidden {
    display: none;
}

.timer-bar-bg {
    flex: 1;
    height: 4px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 999px;
    overflow: hidden;
}

.timer-bar {
    height: 4px;
    background: var(--error-gradient);
    width: 100%;
    transition: width 0.1s linear;
}

.timer-text {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--error-color);
    min-width: 3ch;
}

/* ===== Action Button Layouts ===== */
.action-section {
    margin-bottom: var(--spacing-xl);
}

.full-width {
    width: 100%;
}

.btn-icon-large {
    font-size: 2rem;
}

.btn-text-content {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
}

.btn-main-text {
    font-size: 1.125rem;
    font-weight: 700;
}

.btn-sub-text {
    font-size: 0.875rem;
    opacity: 0.7;
}

/* ===== Mastery Stats ===== */
.mastery-stats-container {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.mastery-stat-card {
    background: var(--bg-card);
    border: 1px solid rgba(255, 255, 255, 0.05);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    transition: all var(--transition-normal);
}

.mastery-stat-card:hover {
    transform: translateY(-2px);
    border-color: rgba(255, 255, 255, 0.1);
    background: rgba(255, 255, 255, 0.05);
}

.mastery-icon {
    font-size: 1.5rem;
}

.mastery-info {
    display: flex;
    flex-direction: column;
}

.mastery-count {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1;
}

.mastery-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-top: 2px;
}

.mastery-stat-card.mastered {
    border-bottom: 3px solid var(--success-color);
}

.mastery-stat-card.learning {
    border-bottom: 3px solid #f1c40f;
}

.mastery-stat-card.needs-practice {
    border-bottom: 3px solid var(--error-color);
}

@media (max-width: 768px) {
    .mastery-stats-container {
        grid-template-columns: 1fr;
    }
}

/* ===== Responsive Design ===== */
@media (max-width: 768px) {
    .container {
        padding: var(--spacing-md);
    }

    .title {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .difficulty-grid {
        grid-template-columns: 1fr;
    }

    .stats-preview {
        grid-template-columns: 1fr;
    }

    .form-grid {
        grid-template-columns: 1fr;
    }

    .results-actions {
        grid-template-columns: 1fr;
    }

    .verb-word {
        font-size: 2rem;
    }

    .results-title {
        font-size: 1.75rem;
    }
}

/* ===== SVG Gradient Definition ===== */
svg defs {
    display: none;
}