:root {
    --color-bg: #f8f9fc;
    --color-surface: #ffffff;
    --color-primary: #6366f1;
    --color-primary-light: #818cf8;
    --color-primary-subtle: #eef2ff;
    --color-text: #1e293b;
    --color-text-secondary: #64748b;
    --color-text-muted: #94a3b8;
    --color-border: #e2e8f0;
    --color-error: #ef4444;
    --color-error-bg: #fef2f2;
    --color-success: #10b981;
    
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.08);
    
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    
    --transition: 0.2s ease;
}

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

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family);
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100vh;
}

/* App Container */
.app {
    max-width: 720px;
    margin: 0 auto;
    padding: 60px 24px 80px;
}

/* Header */
.header {
    text-align: center;
    margin-bottom: 48px;
}

.header__title {
    font-size: 1.75rem;
    font-weight: 600;
    color: var(--color-text);
    letter-spacing: -0.02em;
    margin-bottom: 8px;
}

.header__subtitle {
    font-size: 0.9375rem;
    color: var(--color-text-muted);
    font-weight: 400;
}

/* Input Section */
.input-section {
    margin-bottom: 40px;
}

.input-form {
    width: 100%;
}

.input-wrapper {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.input-field {
    width: 100%;
    padding: 16px 20px;
    font-size: 1rem;
    font-family: inherit;
    color: var(--color-text);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    outline: none;
    transition: border-color var(--transition), box-shadow var(--transition);
}

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

.input-field:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-subtle);
}

.btn-submit {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 14px 28px;
    font-size: 0.9375rem;
    font-weight: 500;
    font-family: inherit;
    color: #ffffff;
    background: var(--color-primary);
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: background var(--transition), transform var(--transition);
}

.btn-submit:hover {
    background: var(--color-primary-light);
}

.btn-submit:active {
    transform: scale(0.98);
}

.btn-submit.loading {
    pointer-events: none;
    opacity: 0.8;
}

.btn-submit.loading .btn-text {
    opacity: 0;
}

.btn-submit.loading .btn-loader {
    display: block;
}

.btn-loader {
    display: none;
    position: absolute;
    width: 18px;
    height: 18px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top-color: #ffffff;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Results Section */
.results {
    display: none;
    flex-direction: column;
    gap: 24px;
}

.results.visible {
    display: flex;
}

/* Predictions Grid */
.predictions-grid {
    display: grid;
    gap: 12px;
}

.prediction-card {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 20px;
    background: var(--color-surface);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
    transition: box-shadow var(--transition);
}

.prediction-card:hover {
    box-shadow: var(--shadow-md);
}

.prediction-rank {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--color-primary);
    background: var(--color-primary-subtle);
    border-radius: var(--radius-sm);
    flex-shrink: 0;
}

.prediction-content {
    flex: 1;
    min-width: 0;
}

.prediction-word {
    font-size: 1.0625rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 4px;
}

.prediction-reasoning {
    font-size: 0.8125rem;
    color: var(--color-text-secondary);
    line-height: 1.5;
}

.prediction-confidence {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 4px;
    flex-shrink: 0;
}

.confidence-value {
    font-size: 1rem;
    font-weight: 600;
    color: var(--color-primary);
}

.confidence-bar {
    width: 60px;
    height: 4px;
    background: var(--color-border);
    border-radius: 2px;
    overflow: hidden;
}

.confidence-fill {
    height: 100%;
    background: var(--color-primary);
    border-radius: 2px;
    transition: width 0.5s ease;
}

/* Section Cards */
.chart-card,
.analysis-card {
    padding: 24px;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
}

.section-title {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 20px;
}

/* Chart Container */
.chart-container {
    position: relative;
    height: 240px;
}

/* Analysis Grid */
.analysis-grid {
    display: grid;
    gap: 20px;
}

.analysis-item {
    padding-bottom: 16px;
    border-bottom: 1px solid var(--color-border);
}

.analysis-item:last-child {
    padding-bottom: 0;
    border-bottom: none;
}

.analysis-label {
    display: block;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.04em;
    margin-bottom: 6px;
}

.analysis-text {
    font-size: 0.9375rem;
    color: var(--color-text);
    line-height: 1.6;
}

/* Error Message */
.error-message {
    display: none;
    padding: 16px 20px;
    background: var(--color-error-bg);
    border: 1px solid var(--color-error);
    border-radius: var(--radius-md);
    margin-top: 20px;
}

.error-message.visible {
    display: block;
}

.error-message p {
    font-size: 0.875rem;
    color: var(--color-error);
}

/* Responsive */
@media (min-width: 540px) {
    .input-wrapper {
        flex-direction: row;
    }
    
    .btn-submit {
        flex-shrink: 0;
    }
    
    .analysis-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .analysis-item {
        padding-bottom: 0;
        border-bottom: none;
    }
}

@media (max-width: 480px) {
    .app {
        padding: 40px 16px 60px;
    }
    
    .header__title {
        font-size: 1.5rem;
    }
    
    .prediction-card {
        flex-wrap: wrap;
    }
    
    .prediction-confidence {
        width: 100%;
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
        padding-top: 12px;
        margin-top: 4px;
        border-top: 1px solid var(--color-border);
    }
    
    .confidence-bar {
        width: 120px;
    }
}