/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-card: #1e293b;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --accent-blue: #3b82f6;
    --accent-green: #10b981;
    --accent-red: #ef4444;
    --accent-yellow: #f59e0b;
    --border-color: #334155;
    --radius: 12px;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
}

html {
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.5;
    min-height: 100vh;
    padding-bottom: env(safe-area-inset-bottom);
}

/* Header */
.header {
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
    padding: 1.5rem 1rem;
    text-align: center;
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid var(--border-color);
}

.header h1 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 0.25rem;
}

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

/* Container */
.container {
    max-width: 600px;
    margin: 0 auto;
    padding: 1rem;
}

/* Summary Cards - Mobile Grid */
.summary-cards {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.card {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 1rem;
    border: 1px solid var(--border-color);
}

.summary-card {
    text-align: center;
    padding: 1.25rem 0.75rem;
}

.card-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--accent-blue);
    line-height: 1.2;
}

.card-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-top: 0.25rem;
}

.summary-card:nth-child(3) .card-value {
    color: var(--accent-green);
}

.evolution-up .card-value { color: var(--accent-green); }
.evolution-down .card-value { color: var(--accent-red); }
.evolution-flat .card-value { color: var(--text-secondary); }

/* Stats Row */
.stats-row {
    display: flex;
    justify-content: space-around;
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 1rem;
    margin-bottom: 1rem;
    border: 1px solid var(--border-color);
}

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

.stat-number {
    display: block;
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.stat-label {
    font-size: 0.7rem;
    color: var(--text-secondary);
    text-transform: uppercase;
}

/* Chart Section */
.chart-section h2 {
    font-size: 1rem;
    margin-bottom: 1rem;
}

.chart-container {
    position: relative;
    height: 200px;
    width: 100%;
}

/* Section Cards */
.card h2 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.card + .card {
    margin-top: 1rem;
}

/* Phrase Tags */
.phrase-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.phrase-tag {
    display: inline-block;
    padding: 0.375rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.875rem;
    font-weight: 500;
}

.phrase-tag.mastered {
    background: rgba(16, 185, 129, 0.15);
    color: var(--accent-green);
    border: 1px solid rgba(16, 185, 129, 0.3);
}

.phrase-tag.correct {
    background: rgba(59, 130, 246, 0.15);
    color: var(--accent-blue);
    border: 1px solid rgba(59, 130, 246, 0.3);
}

.phrase-tag.error {
    background: rgba(239, 68, 68, 0.15);
    color: var(--accent-red);
    border: 1px solid rgba(239, 68, 68, 0.3);
}

/* Error List */
.error-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.error-item {
    padding: 0.75rem;
    background: rgba(239, 68, 68, 0.05);
    border-radius: 8px;
    border-left: 3px solid var(--accent-red);
}

.error-type {
    font-size: 0.75rem;
    text-transform: uppercase;
    color: var(--accent-yellow);
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.error-example {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9375rem;
}

.error-example .wrong {
    color: var(--accent-red);
}

.error-example .arrow {
    color: var(--text-secondary);
}

.error-example .correct {
    color: var(--accent-green);
}

.error-note {
    font-size: 0.8125rem;
    color: var(--text-secondary);
    margin-top: 0.5rem;
    font-style: italic;
}

/* Conversation List */
.conversation-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.conversation-item {
    padding: 1rem;
    background: var(--bg-primary);
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.conv-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}

.conv-channel {
    font-size: 1.25rem;
}

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

.conv-energy {
    margin-left: auto;
    font-size: 0.75rem;
    padding: 0.25rem 0.5rem;
    background: rgba(245, 158, 11, 0.15);
    color: var(--accent-yellow);
    border-radius: 4px;
}

.conv-stats {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    font-size: 0.8125rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.conv-note {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-style: italic;
    margin-bottom: 0.5rem;
}

.conv-phrases {
    display: flex;
    flex-wrap: wrap;
    gap: 0.375rem;
    margin-top: 0.5rem;
}

.conv-phrases .phrase-tag {
    font-size: 0.8125rem;
    padding: 0.25rem 0.5rem;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 2rem;
    color: var(--text-secondary);
    font-style: italic;
}

/* Footer */
.footer {
    text-align: center;
    padding: 2rem 1rem;
    font-size: 0.75rem;
    color: var(--text-secondary);
}

/* Desktop enhancements */
@media (min-width: 640px) {
    .container {
        padding: 1.5rem;
    }
    
    .summary-cards {
        grid-template-columns: repeat(4, 1fr);
    }
    
    .chart-container {
        height: 280px;
    }
    
    .card {
        padding: 1.5rem;
    }
}

/* Touch targets */
@media (hover: none) and (pointer: coarse) {
    .phrase-tag,
    .conv-energy {
        min-height: 44px;
        display: inline-flex;
        align-items: center;
    }
}