:root {
    /* Primary Colors */
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #dbeafe;
    --primary-hover: #1d4ed8;
    --primary-shadow: rgb(37 99 235 / 25%);
    
    /* Legacy Primary (for backward compatibility) */
    --primary-color: var(--primary);
    --primary-color-light: var(--primary-light);
    
    /* Semantic Colors */
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --info: #3b82f6;
    --accent: #36cfc9;
    
    /* Legacy Semantic (for backward compatibility) */
    --success-color: var(--success);
    --warning-color: var(--warning);
    --danger-color: var(--danger);
    
    /* Surface Colors */
    --surface: #ffffff;
    --surface-muted: #f4f6fb;
    --surface-elevated: #ffffff;
    --background: #f8fafc;
    
    /* Legacy Surface (for backward compatibility) */
    --surface-color: var(--surface);
    --light-bg: var(--background);
    --secondary-bg: #e2e8f0;
    --bg-primary: var(--surface);
    --bg-secondary: var(--background);
    
    /* Border Colors */
    --border: #e2e8f0;
    --border-light: #f1f5f9;
    --border-dark: #cbd5e1;
    
    /* Legacy Border (for backward compatibility) */
    --border-color: var(--border);
    
    /* Text Colors */
    --text-main: #0f172a;
    --text-muted: #64748b;
    --text-light: #94a3b8;
    --text-inverse: #ffffff;
    
    /* Legacy Text (for backward compatibility) */
    --text-primary: var(--text-main);
    --text-secondary: var(--text-muted);
    --secondary-color: #334155;
    
    /* Shadow System */
    --shadow-soft: 0 20px 45px rgba(15, 23, 42, 0.08);
    --shadow-sm: 0 1px 2px rgb(15 23 42 / 0.08);
    --shadow-md: 0 4px 12px rgb(15 23 42 / 0.08);
    --shadow-lg: 0 12px 24px rgb(15 23 42 / 0.12);
    --shadow-xl: 0 20px 25px rgb(15 23 42 / 0.1);
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.75rem;
    --radius-lg: 1.5rem;
    --radius-xl: 2rem;
    --radius-full: 9999px;
    --radius: var(--radius-md);
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    
    /* Layout */
    --max-width-reading: 720px;
    --max-width-content: 1200px;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #2563eb 0%, #1d4ed8 100%);
    
    /* Transition */
    --transition: all 0.2s ease;
    
    /* Angle Converter Variables (for educational content styling) */
    --angle-primary: #2563eb;
    --angle-primary-dark: #1d4ed8;
    --angle-accent: #0ea5e9;
    --angle-surface: #ffffff;
    --angle-border: #e2e8f0;
    --angle-text: #0f172a;
    --angle-muted: #64748b;
    --angle-success: #22c55e;
    --angle-radius-lg: 1.5rem;
    --angle-radius-md: 1rem;
    --angle-radius-sm: 0.75rem;
    --angle-shadow-sm: 0 8px 24px rgba(15, 23, 42, 0.08);
    --angle-shadow-lg: 0 30px 60px rgba(37, 99, 235, 0.12);
}

.sum-calculator-page {
    padding: 2rem 0;
}

.calculator-intro {
    margin-bottom: 3rem;
}

.calculator-title {
    font-size: clamp(2.25rem, 4vw, 3rem);
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
    line-height: 1.1;
}

.calculator-subtitle {
    font-size: 1.15rem;
    color: var(--text-secondary);
    margin: 0 0 1rem;
    max-width: 760px;
}

.calculator-meta {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    justify-content: flex-start;
    padding: 0;
    margin: 0;
}

.meta-chip {
    background: var(--surface-color);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    border-radius: 9999px;
    padding: 0.45rem 0.95rem;
    font-size: 0.95rem;
    font-weight: 600;
    box-shadow: var(--shadow-sm);
}

.calculator-main {
    background: var(--surface-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    padding: clamp(1.5rem, 3vw, 2.5rem);
    border: 1px solid rgba(148, 163, 184, 0.25);
}

.calculator-card {
    padding: 0rem 2rem;
    height: 100%;
}

@media (max-width: 768px) {
    .calculator-card {
        padding: 0rem 1rem;
    }
}

.input-group {
    margin-bottom: 1.5rem;
}

.input-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
    font-size: 1rem;
}

.tooltip-wrapper {
    position: relative;
    display: inline-flex;
    align-items: center;
}

.tooltip-trigger {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 0.75rem;
    font-weight: 600;
    cursor: help;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.tooltip-trigger:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.tooltip-content {
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%) translateY(-8px);
    background: var(--text-primary);
    color: white;
    padding: 0.5rem 0.75rem;
    border-radius: 6px;
    font-size: 0.875rem;
    white-space: nowrap;
    opacity: 0;
    pointer-events: none;
    transition: var(--transition);
    z-index: 1000;
    margin-bottom: 0.5rem;
}

.tooltip-content::after {
    content: '';
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    border: 6px solid transparent;
    border-top-color: var(--text-primary);
}

.tooltip-trigger:hover + .tooltip-content,
.tooltip-trigger:focus + .tooltip-content {
    opacity: 1;
}

.number-input {
    width: 100%;
    padding: 1rem;
    font-size: 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius);
    background: var(--bg-primary);
    color: var(--text-primary);
    resize: vertical;
    min-height: 150px;
    transition: var(--transition);
}

.number-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.number-input::placeholder {
    color: var(--text-secondary);
}

.button-group {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.btn {
    padding: 0.875rem 1.75rem;
    font-size: 1rem;
    font-weight: 600;
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    min-height: 48px;
}

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

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

.btn-secondary:hover {
    background: var(--border-color);
}

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

.results-section {
    margin-top: 2rem;
    padding-top: 2rem;
    border-top: 2px solid var(--border-color);
    display: none;
}

.results-section.show {
    display: block;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.sum-display {
    text-align: center;
    padding: 2rem;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    border-radius: var(--radius-lg);
    color: white;
    margin-bottom: 2rem;
}

.sum-label {
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    opacity: 0.9;
    margin-bottom: 0.5rem;
}

.sum-value {
    font-size: clamp(2rem, 5vw, 3.5rem);
    font-weight: 800;
    word-break: break-all;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--bg-secondary);
    padding: 1.25rem;
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
}

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

.stat-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.action-buttons {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
    margin-top: 1.5rem;
}

.btn-copy {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
    padding: 0.75rem 1.25rem;
    font-size: 0.875rem;
}

.btn-copy:hover {
    background: var(--border-color);
}

.share-container {
    margin-top: 1rem;
}

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

.share-buttons {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.share-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
    padding: 0.65rem 0.75rem;
    border-radius: 0.75rem;
    font-size: 0.85rem;
    font-weight: 600;
    text-decoration: none;
    color: #ffffff;
    transition: all 0.3s ease;
    border: none;
}

.share-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 20px rgba(15, 23, 42, 0.2);
    color: #ffffff;
    text-decoration: none;
}

.share-x {
    background: #111827;
}

.share-facebook {
    background: #1877f2;
}

.share-linkedin {
    background: #0a66c2;
}

.share-reddit {
    background: #ff4500;
}

.share-telegram {
    background: #229ed9;
}

.share-whatsapp {
    background: #25d366;
}

.share-btn svg,
.share-btn i {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
}

.toast {
    position: fixed;
    top: 1.5rem;
    right: 1.5rem;
    background: var(--text-primary);
    color: white;
    padding: 1rem 1.5rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    z-index: 1000;
    transform: translateX(400px);
    transition: var(--transition);
    max-width: 300px;
}

.toast.show {
    transform: translateX(0);
}

.toast.success {
    background: var(--success-color);
}

.toast.error {
    background: var(--danger-color);
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

.angle-seo-section {
    padding: 2rem 0;
}

.angle-card {
    background: var(--angle-surface);
    border-radius: var(--angle-radius-lg);
    padding: clamp(2rem, 4vw, 3rem);
    box-shadow: var(--angle-shadow-sm);
    border: 1px solid var(--angle-border);
}

.angle-education-card {
    margin: 0 auto;
}

.angle-education-card h2 {
    font-size: clamp(1.75rem, 3vw, 2.25rem);
    font-weight: 800;
    color: var(--angle-text);
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.angle-education-card h3.h4 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--angle-text);
    margin-top: 2rem;
    margin-bottom: 1rem;
}

.angle-education-card h3 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--angle-text);
    margin-top: 2rem;
    margin-bottom: 1rem;
}

.angle-education-card p {
    font-size: 1rem;
    line-height: 1.7;
    color: var(--text-secondary);
    margin-bottom: 1.25rem;
}

.angle-education-card a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}

.angle-education-card a:hover {
    text-decoration: underline;
}

.infographic-box {
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 2rem;
    margin: 2rem 0;
}

.infographic-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 1.5rem;
    text-align: center;
}

.infographic-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.infographic-item {
    background: var(--bg-primary);
    padding: 1.5rem;
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
}

.infographic-item-title {
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.infographic-item-content {
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Calculator Form Styles */
.calculator-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.status-bar {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem;
    border-radius: var(--radius-md);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.status-info {
    background: var(--primary-light);
    color: var(--primary-dark);
    border: 1px solid var(--primary-color);
}

.input-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
}

.label-title {
    flex: 1;
}

.calculator-input {
    width: 100%;
    padding: 1rem;
    font-size: 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--surface-color);
    color: var(--text-primary);
    resize: vertical;
    min-height: 150px;
    transition: var(--transition);
}

.calculator-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px var(--primary-shadow);
}

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

.calculate-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 0.875rem 1.75rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    min-height: 48px;
}

.calculate-btn:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.ghost-btn {
    background: var(--surface-color);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
    padding: 0.875rem 1.75rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    min-height: 48px;
}

.ghost-btn:hover {
    background: var(--border-color);
}

/* Results Container */
.results-container {
    background: var(--surface-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    padding: clamp(1.5rem, 3vw, 2.5rem);
    border: 1px solid rgba(148, 163, 184, 0.25);
    height: 100%;
}

.results-header {
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid var(--border-color);
}

.results-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: 0;
}

/* Empty State */
#emptyState {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 400px;
    text-align: center;
}

/* Tooltip Styles */
.tooltip {
    position: relative;
    display: inline-flex;
    align-items: center;
}

.tooltiptext {
    visibility: hidden;
    width: 200px;
    background-color: var(--text-primary);
    color: white;
    text-align: left;
    border-radius: var(--radius-sm);
    padding: 0.5rem 0.75rem;
    position: absolute;
    z-index: 1000;
    bottom: 125%;
    left: 50%;
    margin-left: -100px;
    opacity: 0;
    transition: opacity 0.3s;
    font-size: 0.875rem;
    line-height: 1.4;
}

.tooltip-trigger:hover + .tooltiptext,
.tooltip-trigger:focus + .tooltiptext {
    visibility: visible;
    opacity: 1;
}

.tooltiptext::after {
    content: "";
    position: absolute;
    top: 100%;
    left: 50%;
    margin-left: -5px;
    border-width: 5px;
    border-style: solid;
    border-color: var(--text-primary) transparent transparent transparent;
}

/* Copy Buttons */
.copy-buttons-row {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.copy-buttons-row .copy-button {
    flex: 1 1 auto;
    min-width: 140px;
}

.copy-button {
    width: 48%;
    background: #f1f5f9;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #405063 !important;
    border: 1px solid #dde3e7;
    font-size: 14px;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    gap: 0.5rem;
}

.copy-button:hover {
    background: #e2e8f0;
    border-color: #94a3b8;
    transform: translateY(-1px);
}

.copy-button.copied {
    background: #10b981;
    border-color: #10b981;
    color: #ffffff !important;
}

.copy-button svg {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
}

.result-actions {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

/* Infographic Styles (from angle converter) */
.infographic-conversion-formula {
    margin: 2rem 0;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.formula-box {
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.08) 0%, rgba(14, 165, 233, 0.08) 100%);
    border-radius: var(--angle-radius-md);
    padding: 1.5rem;
    border: 2px solid rgba(37, 99, 235, 0.2);
}

.formula-label {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--angle-primary);
    margin-bottom: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.formula-content {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--angle-text);
    margin-bottom: 0.75rem;
}

.formula-example {
    font-size: 0.9rem;
    color: var(--angle-muted);
    font-style: italic;
}

.infographic-sum-visual {
    margin: 2rem 0;
    padding: 1.5rem;
    background: #f8fafc;
    border-radius: var(--angle-radius-md);
    border: 1px solid rgba(148, 163, 184, 0.25);
}

.division-title {
    font-size: 1rem;
    font-weight: 700;
    color: var(--angle-text);
    text-align: center;
}

.sum-visual-row {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
    gap: 1rem;
    margin-top: 1.5rem;
    padding: 1.5rem 0;
}

.sum-visual-number {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.sum-visual-operator {
    font-size: 1.75rem;
    font-weight: 600;
    color: var(--angle-muted);
    padding: 0 0.5rem;
}

.sum-visual-result {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.infographic-conversion-chart {
    margin: 2rem 0;
    padding: 1.5rem;
    background: #f8fafc;
    border-radius: var(--angle-radius-md);
    border: 1px solid rgba(148, 163, 184, 0.25);
}

.chart-title {
    font-size: 1rem;
    font-weight: 700;
    color: var(--angle-text);
    margin-bottom: 1.5rem;
    text-align: center;
}

.conversion-bars {
    display: grid;
    gap: 1.25rem;
}

.conversion-bar-item {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.bar-label {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--angle-text);
}

.bar-container {
    width: 100%;
    height: 36px;
    background: #e2e8f0;
    border-radius: var(--angle-radius-sm);
    overflow: hidden;
    position: relative;
}

.bar-fill {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: flex-end;
    padding-right: 0.75rem;
    border-radius: var(--angle-radius-sm);
    transition: width 0.6s ease;
}

.bar-value {
    font-size: 0.85rem;
    font-weight: 700;
    color: #ffffff;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
}

@media (max-width: 768px) {
    .copy-buttons-row {
        flex-direction: column;
    }
    
    .copy-buttons-row .copy-button {
        width: 100%;
    }
    
    .share-buttons {
        justify-content: center;
    }
    
    .share-btn {
        flex: 1;
        min-width: 100px;
        justify-content: center;
    }
    
    .infographic-conversion-formula {
        grid-template-columns: 1fr;
    }
    
    .sum-visual-row {
        gap: 0.5rem;
        padding: 1rem 0;
    }
    
    .sum-visual-number div:first-child,
    .sum-visual-result div:first-child {
        font-size: 1.5rem !important;
    }
    
    .sum-visual-operator {
        font-size: 1.25rem !important;
        padding: 0 0.25rem !important;
    }
    
    .bar-value {
        font-size: 0.75rem;
    }
}