/* WritingTutor - Main Stylesheet */

:root {
    --primary: #4a90d9;
    --primary-dark: #357abd;
    --success: #5cb85c;
    --warning: #f0ad4e;
    --danger: #d9534f;
    --info: #5bc0de;
    --bg: #f5f7fa;
    --card-bg: #ffffff;
    --text: #333333;
    --text-light: #666666;
    --border: #e0e0e0;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    --radius: 8px;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #1a1a2e;
        --card-bg: #16213e;
        --text: #e0e0e0;
        --text-light: #a0a0a0;
        --border: #2a2a4e;
        --shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
    }
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
header {
    background: var(--card-bg);
    box-shadow: var(--shadow);
    padding: 16px 0;
    flex-shrink: 0;
}

.header-inner {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 10px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo h1 {
    font-size: 24px;
    font-weight: 700;
    color: var(--text);
}

.logo .accent {
    color: var(--primary);
}

.tagline {
    color: var(--text-light);
    font-size: 14px;
}

/* Main */
main {
    flex: 1;
    max-width: 1100px;
    width: 100%;
    margin: 0 auto;
    padding: 24px 20px;
}

/* Cards */
.card {
    background: var(--card-bg);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 24px;
    margin-bottom: 20px;
}

.card h3 {
    margin-bottom: 12px;
    font-size: 18px;
    color: var(--text);
}

.panel-hint {
    color: var(--text-light);
    font-size: 13px;
    margin-bottom: 12px;
}

/* Input Section */
.input-section {
    margin-bottom: 20px;
}

.input-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 12px;
}

.input-header h2 {
    font-size: 20px;
    color: var(--text);
}

.input-actions {
    display: flex;
    gap: 8px;
}

#textInput {
    width: 100%;
    min-height: 200px;
    border: 2px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
    font-size: 15px;
    font-family: inherit;
    line-height: 1.7;
    resize: vertical;
    background: var(--card-bg);
    color: var(--text);
    transition: border-color 0.2s;
}

#textInput:focus {
    outline: none;
    border-color: var(--primary);
}

.input-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: 12px;
}

.char-count {
    color: var(--text-light);
    font-size: 13px;
}

/* Buttons */
.btn-primary, .btn-secondary {
    border: none;
    border-radius: var(--radius);
    padding: 10px 24px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.btn-primary {
    background: var(--primary);
    color: #fff;
}

.btn-primary:hover:not(:disabled) {
    background: var(--primary-dark);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(74, 144, 217, 0.3);
}

.btn-primary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-secondary {
    background: transparent;
    color: var(--primary);
    border: 1.5px solid var(--primary);
    padding: 8px 16px;
}

.btn-secondary:hover {
    background: var(--primary);
    color: #fff;
}

/* Spinner */
.spinner {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top-color: #fff;
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
}

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

/* Summary Card */
.summary-card {
    text-align: center;
}

.score-circle-container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 40px;
    flex-wrap: wrap;
    margin-bottom: 24px;
}

.score-circle {
    width: 140px;
    height: 140px;
    border-radius: 50%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    position: relative;
}

.score-circle::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: 50%;
    background: conic-gradient(var(--primary) var(--score-deg, 0deg), var(--border) 0deg);
    -webkit-mask: radial-gradient(circle, transparent 58px, black 60px);
    mask: radial-gradient(circle, transparent 58px, black 60px);
}

.score-value {
    font-size: 42px;
    font-weight: 700;
    color: var(--primary);
    line-height: 1;
    z-index: 1;
}

.score-label {
    font-size: 12px;
    color: var(--text-light);
    z-index: 1;
    margin-top: 4px;
}

.score-grade {
    text-align: left;
}

.grade-badge {
    display: inline-block;
    font-size: 36px;
    font-weight: 800;
    padding: 8px 24px;
    border-radius: var(--radius);
    color: #fff;
    background: var(--primary);
}

.grade-feedback {
    color: var(--text-light);
    font-size: 14px;
    margin-top: 8px;
    max-width: 300px;
}

.summary-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 16px;
    padding-top: 20px;
    border-top: 1px solid var(--border);
}

.summary-stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
}

.summary-stat-item .stat-value {
    font-size: 24px;
    font-weight: 700;
    color: var(--text);
}

.summary-stat-item .stat-label {
    font-size: 12px;
    color: var(--text-light);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.ielts-band {
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid var(--border);
}

.ielts-label {
    color: var(--text-light);
    font-size: 14px;
}

.ielts-value {
    font-weight: 700;
    font-size: 18px;
    color: var(--primary);
    margin-left: 8px;
}

/* Tab Navigation */
.tab-nav {
    display: flex;
    gap: 4px;
    margin-bottom: 0;
    flex-wrap: wrap;
    overflow-x: auto;
}

.tab-btn {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-bottom: none;
    border-radius: var(--radius) var(--radius) 0 0;
    padding: 10px 20px;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-light);
    cursor: pointer;
    transition: all 0.2s;
    white-space: nowrap;
}

.tab-btn:hover {
    color: var(--primary);
    background: var(--bg);
}

.tab-btn.active {
    color: var(--primary);
    border-color: var(--primary);
    background: var(--card-bg);
    position: relative;
    z-index: 1;
}

/* Tab Panels */
.tab-panel {
    display: none;
    border: 1px solid var(--border);
    border-radius: 0 var(--radius) var(--radius) var(--radius);
    background: var(--card-bg);
    overflow: hidden;
}

.tab-panel.active {
    display: block;
}

.tab-panel .card {
    box-shadow: none;
    margin-bottom: 0;
    border-bottom: 1px solid var(--border);
}

.tab-panel .card:last-child {
    border-bottom: none;
    margin-bottom: 20px;
}

/* Annotated Text */
.annotated-text {
    font-family: Georgia, 'Times New Roman', serif;
    font-size: 16px;
    line-height: 2;
    white-space: pre-wrap;
    word-wrap: break-word;
}

.error-highlight {
    background: #fff3cd;
    border-bottom: 2px solid var(--warning);
    cursor: pointer;
    border-radius: 3px;
    padding: 1px 3px;
    position: relative;
    transition: background 0.2s;
}

.error-highlight:hover {
    background: #ffe0a3;
}

.error-highlight.grammar {
    background: #fdd;
    border-bottom-color: var(--danger);
}

.error-highlight.spelling {
    background: #cfe;
    border-bottom-color: var(--info);
}

.error-highlight.punctuation {
    background: #fce;
    border-bottom-color: #b36;
}

.error-highlight.typography {
    background: #e8e8e8;
    border-bottom-color: #999;
}

.error-highlight.capitalisation {
    background: #eef;
    border-bottom-color: #66c;
}

.error-tooltip {
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    background: #333;
    color: #fff;
    padding: 8px 12px;
    border-radius: 6px;
    font-size: 13px;
    font-family: sans-serif;
    white-space: normal;
    width: max-content;
    max-width: 300px;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s;
    z-index: 100;
    line-height: 1.4;
}

.error-highlight:hover .error-tooltip {
    opacity: 1;
}

/* Error List */
.error-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.error-item {
    display: flex;
    gap: 12px;
    padding: 12px;
    border: 1px solid var(--border);
    border-radius: 6px;
    background: var(--bg);
}

.error-item .error-num {
    flex-shrink: 0;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    background: var(--danger);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 13px;
    font-weight: 700;
}

.error-item .error-content {
    flex: 1;
}

.error-item .error-category {
    display: inline-block;
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    padding: 2px 8px;
    border-radius: 3px;
    margin-bottom: 4px;
}

.error-item .error-message {
    font-size: 14px;
    color: var(--text);
    margin-bottom: 6px;
}

.error-item .error-context {
    font-family: monospace;
    font-size: 13px;
    color: var(--text-light);
    padding: 4px 8px;
    background: var(--card-bg);
    border-radius: 4px;
    border: 1px solid var(--border);
}

.error-item .error-suggestions {
    margin-top: 6px;
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}

.suggestion-chip {
    display: inline-block;
    padding: 4px 12px;
    background: var(--success);
    color: #fff;
    border-radius: 12px;
    font-size: 13px;
    cursor: default;
}

/* Category Chart */
.category-chart {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    margin-bottom: 16px;
}

.category-bar {
    flex: 1;
    min-width: 120px;
}

.category-bar .cat-label {
    font-size: 13px;
    color: var(--text-light);
    margin-bottom: 4px;
}

.category-bar .cat-bar-bg {
    height: 8px;
    background: var(--border);
    border-radius: 4px;
    overflow: hidden;
}

.category-bar .cat-bar-fill {
    height: 100%;
    border-radius: 4px;
    transition: width 0.5s ease;
}

.category-bar .cat-count {
    font-size: 12px;
    color: var(--text-light);
    margin-top: 2px;
}

/* Statistics Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 16px;
}

.stat-box {
    padding: 16px;
    background: var(--bg);
    border-radius: var(--radius);
    text-align: center;
}

.stat-box .stat-value {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary);
}

.stat-box .stat-label {
    font-size: 13px;
    color: var(--text-light);
    margin-top: 4px;
}

/* Readability Metrics */
.readability-metrics {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.readability-item {
    display: flex;
    align-items: center;
    gap: 12px;
}

.readability-item .rm-label {
    width: 200px;
    font-size: 14px;
    color: var(--text);
    flex-shrink: 0;
}

.readability-item .rm-bar-bg {
    flex: 1;
    height: 10px;
    background: var(--border);
    border-radius: 5px;
    overflow: hidden;
}

.readability-item .rm-bar-fill {
    height: 100%;
    border-radius: 5px;
    transition: width 0.5s ease;
}

.readability-item .rm-value {
    width: 80px;
    font-size: 14px;
    font-weight: 600;
    color: var(--text);
    text-align: right;
    flex-shrink: 0;
}

/* Word Frequency Chart */
.word-freq-chart {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.word-freq-bar {
    display: flex;
    align-items: center;
    gap: 8px;
}

.word-freq-bar .wf-label {
    width: 100px;
    font-size: 13px;
    color: var(--text);
    text-align: right;
}

.word-freq-bar .wf-bar-bg {
    flex: 1;
    height: 20px;
    background: var(--bg);
    border-radius: 3px;
    overflow: hidden;
}

.word-freq-bar .wf-bar-fill {
    height: 100%;
    background: var(--primary);
    border-radius: 3px;
    transition: width 0.5s ease;
}

.word-freq-bar .wf-count {
    width: 30px;
    font-size: 13px;
    color: var(--text-light);
}

/* Suggestion List */
.suggestion-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.suggestion-item {
    display: flex;
    gap: 12px;
    padding: 12px;
    border: 1px solid var(--border);
    border-radius: 6px;
    background: var(--bg);
}

.suggestion-item .sug-icon {
    flex-shrink: 0;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: 700;
    color: #fff;
}

.suggestion-item .sug-content {
    flex: 1;
}

.suggestion-item .sug-category {
    font-size: 12px;
    font-weight: 600;
    color: var(--text-light);
    text-transform: uppercase;
    margin-bottom: 4px;
}

.suggestion-item .sug-message {
    font-size: 14px;
    color: var(--text);
    margin-bottom: 6px;
}

.suggestion-item .sug-suggestions {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}

/* Structure Overview */
.structure-overview {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 16px;
    margin-bottom: 20px;
}

.structure-overview-item {
    text-align: center;
    padding: 16px;
    background: var(--bg);
    border-radius: var(--radius);
}

.structure-overview-item .so-value {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary);
}

.structure-overview-item .so-label {
    font-size: 13px;
    color: var(--text-light);
    margin-top: 4px;
}

/* Structure Details */
.structure-details {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.paragraph-detail {
    padding: 16px;
    background: var(--bg);
    border-radius: var(--radius);
}

.paragraph-detail .pd-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 12px;
}

.paragraph-detail .pd-badge {
    background: var(--primary);
    color: #fff;
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 13px;
    font-weight: 600;
}

.paragraph-detail .pd-meta {
    color: var(--text-light);
    font-size: 13px;
}

.paragraph-detail .pd-metrics {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 8px;
}

.pd-metric {
    text-align: center;
    padding: 8px;
    background: var(--card-bg);
    border-radius: 4px;
}

.pd-metric .pd-m-value {
    font-size: 16px;
    font-weight: 600;
    color: var(--text);
}

.pd-metric .pd-m-label {
    font-size: 11px;
    color: var(--text-light);
}

.pd-transitions {
    margin-top: 8px;
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}

.pd-transition-chip {
    font-size: 12px;
    padding: 2px 8px;
    border-radius: 3px;
    background: var(--info);
    color: #fff;
}

/* Issues List */
.issues-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.issue-item {
    display: flex;
    gap: 10px;
    padding: 10px 12px;
    border-radius: 6px;
    font-size: 14px;
}

.issue-item.warning {
    background: #fff3cd;
    color: #856404;
    border: 1px solid #ffc107;
}

.issue-item.info {
    background: #d1ecf1;
    color: #0c5460;
    border: 1px solid #17a2b8;
}

.issue-item .issue-icon {
    flex-shrink: 0;
}

/* Score Breakdown */
.score-breakdown {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.breakdown-item {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.breakdown-item .bi-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.breakdown-item .bi-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--text);
}

.breakdown-item .bi-score {
    font-size: 24px;
    font-weight: 700;
    color: var(--primary);
}

.breakdown-item .bi-bar-bg {
    height: 12px;
    background: var(--border);
    border-radius: 6px;
    overflow: hidden;
}

.breakdown-item .bi-bar-fill {
    height: 100%;
    border-radius: 6px;
    transition: width 0.5s ease;
}

.breakdown-item .bi-feedback {
    font-size: 14px;
    color: var(--text-light);
    margin-top: 2px;
}

.breakdown-item .bi-details {
    font-size: 13px;
    color: var(--text-light);
    margin-top: 4px;
}


/* AI Detection Panel */
.ai-detection-panel {
    padding: 20px 0;
}

.ai-detection-header {
    display: flex;
    align-items: center;
    gap: 40px;
    flex-wrap: wrap;
    margin-bottom: 30px;
    justify-content: center;
}

.ai-detection-header svg {
    flex-shrink: 0;
}

.ai-detection-title {
    text-align: center;
}

.ai-classification {
    font-size: 24px;
    font-weight: 700;
    font-style: italic;
    color: var(--text);
    margin-bottom: 12px;
}

.ai-probability {
    font-size: 48px;
    font-weight: 800;
    color: var(--primary);
    line-height: 1.1;
}

.ai-prob-label {
    font-size: 16px;
    color: var(--text-light);
    margin-top: 4px;
}

.ai-confidence-breakdown {
    margin-top: 24px;
    padding-top: 24px;
    border-top: 1px solid var(--border);
}

.ai-confidence-title {
    font-size: 20px;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 16px;
}

.ai-confidence-items {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.ai-confidence-item {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.ai-conf-left {
    font-size: 16px;
    color: var(--text);
}

.ai-conf-left strong {
    font-weight: 700;
    color: var(--text);
}

.ai-conf-num {
    color: var(--text-light);
    margin-right: 4px;
}

.ai-conf-bar-bg {
    height: 12px;
    background: var(--border);
    border-radius: 6px;
    overflow: hidden;
}

.ai-conf-bar-fill {
    height: 100%;
    border-radius: 6px;
    transition: width 0.5s ease;
}

.ai-features {
    margin-top: 24px;
    padding-top: 24px;
    border-top: 1px solid var(--border);
}

.ai-features-title {
    font-size: 18px;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 16px;
}

.ai-features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 12px;
}

.ai-feature-item {
    display: flex;
    flex-direction: column;
    gap: 4px;
    padding: 10px 12px;
    background: var(--bg);
    border-radius: 6px;
}

.ai-feature-name {
    font-size: 13px;
    color: var(--text-light);
}

.ai-feature-bar-bg {
    height: 8px;
    background: var(--border);
    border-radius: 4px;
    overflow: hidden;
}

.ai-feature-bar-fill {
    height: 100%;
    border-radius: 4px;
    transition: width 0.5s ease;
}

.ai-feature-value {
    font-size: 13px;
    font-weight: 600;
    color: var(--text);
    text-align: right;
}

.ai-message {
    margin-top: 16px;
    padding: 12px 16px;
    background: #fff3cd;
    color: #856404;
    border-radius: 6px;
    font-size: 14px;
    border: 1px solid #ffc107;
}

/* Footer */
footer {
    text-align: center;
    padding: 20px;
    color: var(--text-light);
    font-size: 13px;
    border-top: 1px solid var(--border);
    background: var(--card-bg);
    flex-shrink: 0;
}

/* Responsive */
@media (max-width: 768px) {
    .header-inner {
        flex-direction: column;
        text-align: center;
    }

    .input-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
    }

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

    .score-circle-container {
        flex-direction: column;
        gap: 20px;
    }

    .tab-nav {
        flex-direction: column;
    }

    .tab-btn {
        border-radius: var(--radius);
        border: 1px solid var(--border);
    }

    .readability-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 4px;
    }

    .readability-item .rm-label {
        width: auto;
    }

    .readability-item .rm-value {
        width: auto;
    }
}