/* ============================================
   RESET & BASE STYLES
   ============================================ */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --color-primary: #2d3c59;
    --color-secondary: #95a5a6;
    --color-accent: #e8e8e8;
    --color-background: #fafafa;
    --color-surface: #ffffff;
    --color-text: #333333;
    --color-text-light: #666666;
    --color-border: #e0e0e0;
    --color-success: #27ae60;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --border-radius: 8px;
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

/* ============================================
   LAYOUT
   ============================================ */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    width: 100%;
}

header {
    background-color: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-lg) 0;
    box-shadow: var(--shadow-sm);
    position: relative;
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
}

header .header-content {
    flex: 1;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--spacing-xs);
}

header .logo {
    height: 60px;
    width: auto;
    max-width: 100%;
    display: block;
}

.tagline {
    color: var(--color-text-light);
    font-size: 1.1rem;
    font-weight: 400;
}

/* Theme Toggle */
.theme-toggle {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    margin-left: var(--spacing-md);
}

.theme-toggle-label {
    font-size: 0.9rem;
    color: var(--color-text-light);
    font-weight: 500;
}

.theme-switch {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 26px;
}

.theme-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.theme-slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--color-secondary);
    transition: var(--transition);
    border-radius: 26px;
}

.theme-slider:before {
    position: absolute;
    content: "";
    height: 20px;
    width: 20px;
    left: 3px;
    bottom: 3px;
    background-color: white;
    transition: var(--transition);
    border-radius: 50%;
}

.theme-switch input:checked + .theme-slider {
    background-color: var(--color-primary);
}

.theme-switch input:checked + .theme-slider:before {
    transform: translateX(24px);
}

.theme-switch input:focus + .theme-slider {
    box-shadow: 0 0 0 3px rgba(44, 62, 80, 0.2);
}

main {
    flex: 1;
    padding: var(--spacing-xl) 0;
}

footer {
    background-color: var(--color-surface);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-md) 0;
    margin-top: var(--spacing-xl);
    text-align: center;
    color: var(--color-text-light);
    font-size: 0.9rem;
}

footer a {
    color: var(--color-text-light);
    text-decoration: none;
    transition: var(--transition);
}

footer a:hover {
    color: var(--color-primary);
    text-decoration: underline;
}

/* ============================================
   INTRO SECTION
   ============================================ */
.intro {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.intro h1 {
    font-size: 2.6rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
    font-weight: 700;
}

.intro h2 {
    font-size: 2rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
    font-weight: 700;
    line-height: 1.2;
}

.intro p {
    font-size: 1.1rem;
    color: var(--color-text-light);
    line-height: 1.8;
}

/* ============================================
   CALCULATOR GRID (HOMEPAGE)
   ============================================ */
.calculators-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-lg);
}

.calculator-card {
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    transition: var(--transition);
    box-shadow: var(--shadow-sm);
    display: flex;
    flex-direction: column;
}

.calculator-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
    border-color: var(--color-secondary);
}

.calculator-icon {
    width: 96px;
    height: 96px;
    background-color: white;
    border-radius: var(--border-radius);
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 8px;
}

.calculator-icon img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    filter: brightness(0) saturate(100%) invert(58%) sepia(45%) saturate(1200%) hue-rotate(340deg) brightness(1.1) contrast(0.9);
}

.calculator-icon svg {
    width: 100%;
    height: 100%;
    color: #d0845c;
    fill: #d0845c;
    transition: transform 0.3s ease;
}

/* Subtle pulse animation on hover */
.calculator-card:hover .calculator-icon {
    animation: pulseIcon 1.5s ease-in-out infinite;
}

@keyframes pulseIcon {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

/* All calculator icons use the same color */
.calculators-grid .calculator-card .calculator-icon img {
    filter: brightness(0) saturate(100%) invert(58%) sepia(45%) saturate(1200%) hue-rotate(340deg) brightness(1.1) contrast(0.9);
}

.calculators-grid .calculator-card .calculator-icon svg {
    color: #d0845c;
    fill: #d0845c;
}

.calculator-card h2 {
    font-size: 2rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
    line-height: 1.2;
}

.calculator-card p {
    color: var(--color-text-light);
    margin-bottom: var(--spacing-md);
    flex: 1;
    line-height: 1.6;
}

/* ============================================
   BUTTONS
   ============================================ */
.btn {
    display: inline-block;
    background-color: var(--color-primary);
    color: white;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    border: none;
    cursor: pointer;
    font-size: 1rem;
    text-align: center;
    width: 100%;
}

.btn:hover {
    background-color: #547792;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

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

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

.btn-secondary:hover {
    background-color: #7f8c8d;
}

/* ============================================
   CALCULATOR PAGE STYLES
   ============================================ */
.calculator-page {
    max-width: 800px;
    margin: 0 auto;
}

.calculator-page h1 {
    font-size: 2.25rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
    font-weight: 700;
}

.calculator-page .description {
    color: var(--color-text-light);
    font-size: 1.05rem;
    margin-bottom: var(--spacing-xl);
    line-height: 1.8;
}

.back-link {
    display: inline-block;
    color: var(--color-primary);
    text-decoration: none;
    margin-bottom: var(--spacing-lg);
    font-weight: 500;
    transition: var(--transition);
}

.back-link:hover {
    color: var(--color-secondary);
    text-decoration: underline;
}

.back-link::before {
    content: "← ";
    margin-right: var(--spacing-xs);
}

/* ============================================
   FORM STYLES
   ============================================ */
.calculator-form {
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
}

.form-group {
    margin-bottom: var(--spacing-md);
}

.form-group label {
    display: block;
    margin-bottom: var(--spacing-xs);
    color: var(--color-text);
    font-weight: 500;
    font-size: 1rem;
}

.form-group input,
.form-group select {
    width: 100%;
    padding: var(--spacing-sm);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-family: inherit;
    transition: var(--transition);
    background-color: var(--color-surface);
    color: var(--color-text);
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(44, 62, 80, 0.1);
}

.form-group input[type="number"] {
    appearance: textfield;
    -moz-appearance: textfield;
}

.form-group input[type="number"]::-webkit-outer-spin-button,
.form-group input[type="number"]::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.form-group small {
    display: block;
    margin-top: var(--spacing-xs);
    color: var(--color-text-light);
    font-size: 0.875rem;
}

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

.radio-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.radio-label {
    display: flex;
    align-items: center;
    padding: var(--spacing-xs);
    cursor: pointer;
    border-radius: var(--border-radius);
    transition: var(--transition);
}

.radio-label:hover {
    background-color: var(--color-accent);
}

.radio-label input[type="radio"] {
    width: auto;
    margin-right: var(--spacing-xs);
    cursor: pointer;
}

.radio-label span {
    color: var(--color-text);
    font-weight: 400;
}

/* ============================================
   DESIGN TIPS SECTION
   ============================================ */
.design-tips-section {
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    margin-top: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
}

.design-tips-section h3 {
    font-size: 1.25rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
    font-weight: 600;
}

.design-tips-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.design-tips-list li {
    padding: var(--spacing-sm) 0;
    padding-left: var(--spacing-lg);
    position: relative;
    color: var(--color-text);
    line-height: 1.6;
}

.design-tips-list li::before {
    content: "💡";
    position: absolute;
    left: 0;
    font-size: 1.1rem;
}

/* ============================================
   RESULT SECTION
   ============================================ */
.result-section {
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    margin-top: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
    display: none;
}

.result-section.show {
    display: block;
}

.result-section h2 {
    font-size: 1.5rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
    font-weight: 600;
    line-height: 1.2;
}

.result-item {
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid var(--color-border);
}

.result-item:last-child {
    border-bottom: none;
}

.result-item strong {
    color: var(--color-primary);
    font-weight: 600;
    display: inline-block;
    min-width: 200px;
}

.result-item span {
    color: var(--color-text);
    font-size: 1.1rem;
}

.result-highlight {
    background-color: var(--color-accent);
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    margin-top: var(--spacing-md);
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--color-primary);
    text-align: center;
}

.result-explanation,
.result-tips {
    background-color: var(--color-accent);
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    margin-top: var(--spacing-md);
}

.result-explanation h3,
.result-tips h3 {
    font-size: 1.1rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
}

.result-explanation p {
    color: var(--color-text);
    line-height: 1.6;
    margin: 0;
}

.result-tips ul {
    list-style: none;
    padding: 0;
    margin: var(--spacing-sm) 0 0 0;
}

.result-tips li {
    color: var(--color-text);
    line-height: 1.6;
    padding: var(--spacing-xs) 0;
    padding-left: var(--spacing-lg);
    position: relative;
}

.result-tips li::before {
    content: "•";
    position: absolute;
    left: var(--spacing-sm);
    color: var(--color-primary);
    font-weight: bold;
    font-size: 1.2rem;
}

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */
@media (max-width: 768px) {
    header .logo {
        height: 45px;
    }

    .tagline {
        font-size: 1rem;
    }

    .calculators-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }

    .calculator-page h1 {
        font-size: 1.75rem;
    }

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

    .container {
        padding: 0 var(--spacing-sm);
    }

    main {
        padding: var(--spacing-lg) 0;
    }
}

@media (max-width: 480px) {
    header .logo {
        height: 35px;
    }

    .calculator-card h2 {
        font-size: 2rem;
    }

    .calculator-page h1 {
        font-size: 1.5rem;
    }
}

/* ============================================
   UTILITY CLASSES
   ============================================ */
.text-center {
    text-align: center;
}

.mt-sm {
    margin-top: var(--spacing-sm);
}

.mt-md {
    margin-top: var(--spacing-md);
}

.mt-lg {
    margin-top: var(--spacing-lg);
}

.mb-sm {
    margin-bottom: var(--spacing-sm);
}

.mb-md {
    margin-bottom: var(--spacing-md);
}

.mb-lg {
    margin-bottom: var(--spacing-lg);
}

/* ============================================
   ABOUT PAGE STYLES
   ============================================ */
.about-content {
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
}

.about-section {
    margin-bottom: var(--spacing-xl);
}

.about-section:last-child {
    margin-bottom: 0;
}

.about-section h2 {
    font-size: 1.5rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
    font-weight: 600;
    line-height: 1.2;
}

.about-section p {
    color: var(--color-text);
    line-height: 1.8;
    margin-bottom: var(--spacing-md);
}

.feature-list {
    list-style-position: inside;
    color: var(--color-text);
    line-height: 1.8;
    margin-left: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.feature-list li {
    margin-bottom: var(--spacing-sm);
    padding-left: var(--spacing-xs);
}

.feature-list strong {
    color: var(--color-primary);
    font-weight: 600;
}

.feature-list ol {
    list-style-type: decimal;
    margin-left: var(--spacing-md);
}

.feature-list ul {
    list-style-type: disc;
    margin-left: var(--spacing-md);
}

/* ============================================
   DARK THEME
   ============================================ */
[data-theme="dark"] {
    --color-primary: #ecf0f1;
    --color-secondary: #bdc3c7;
    --color-accent: #34495e;
    --color-background: #1a1a1a;
    --color-surface: #2d2d2d;
    --color-text: #e0e0e0;
    --color-text-light: #b0b0b0;
    --color-border: #404040;
    --color-success: #2ecc71;
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.4);
}

[data-theme="dark"] .form-group input:focus,
[data-theme="dark"] .form-group select:focus {
    box-shadow: 0 0 0 3px rgba(236, 240, 241, 0.2);
}

[data-theme="dark"] .theme-switch input:focus + .theme-slider {
    box-shadow: 0 0 0 3px rgba(236, 240, 241, 0.2);
}

/* Dark mode switch pointer - dark for better contrast */
[data-theme="dark"] .theme-slider:before {
    background-color: #1a1a1a;
}

/* Dark mode icon background */
[data-theme="dark"] .calculator-icon {
    background-color: #2d2d2d;
}

/* Dark mode button styles - dark text for better contrast */
[data-theme="dark"] .btn {
    background-color: var(--color-primary);
    color: #1a1a1a;
}

[data-theme="dark"] .btn:hover {
    background-color: #547792;
    color: #1a1a1a;
}

[data-theme="dark"] .btn-secondary {
    background-color: var(--color-secondary);
    color: #1a1a1a;
}

[data-theme="dark"] .btn-secondary:hover {
    background-color: #a6b0b3;
    color: #1a1a1a;
}

/* Responsive adjustments for theme toggle */
@media (max-width: 768px) {
    header .container {
        flex-direction: row;
        align-items: center;
        justify-content: space-between;
    }

    header .header-content {
        flex: 1;
        display: flex;
        align-items: center;
        gap: var(--spacing-sm);
    }

    header .tagline {
        display: none;
    }

    .theme-toggle {
        margin-left: 0;
        margin-top: 0;
        align-self: center;
    }
}

/* ============================================
   PRINT STYLES FOR PDF DOWNLOAD
   ============================================ */
@media print {
    body * {
        visibility: hidden;
    }
    
    .result-section,
    .result-section * {
        visibility: visible;
    }
    
    .result-section {
        position: absolute;
        left: 0;
        top: 0;
        width: 100%;
        background: white;
        color: black;
        padding: 20px;
        box-shadow: none;
        border: none;
    }
    
    .btn,
    header,
    footer,
    .calculator-form,
    .back-link,
    .theme-toggle {
        display: none !important;
    }
    
    .result-section h2 {
        color: #000;
        margin-bottom: 20px;
        font-size: 1.5rem;
    }
    
    .result-item {
        border-bottom: 1px solid #ccc;
        padding: 10px 0;
    }
    
    .result-item strong {
        color: #000;
    }
    
    .result-item span {
        color: #000;
    }
    
    .result-highlight {
        background: #f0f0f0;
        color: #000;
        padding: 15px;
        margin-top: 20px;
        border-radius: 5px;
    }
    
    #downloadPdf {
        display: none;
    }
}