/* Modern Custom CSS Variables & Refined High Contrast Themes */
:root {
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-main: #0f172a;
    --text-muted: #475569;
    --border-color: #cbd5e1;
    --input-bg: #ffffff;
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --primary-light: #eff6ff;
    --accent: #059669;
    --accent-bg: #ecfdf5;
    --shadow: 0 10px 25px -5px rgba(15, 23, 42, 0.08), 0 8px 10px -6px rgba(15, 23, 42, 0.04);
    --radius: 16px;
    --transition-speed: 0.2s;
}

[data-theme="dark"] {
    --bg-color: #0b0f19;
    --card-bg: #151e32;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --border-color: #2e3d58;
    --input-bg: #0b0f19;
    --primary: #3b82f6;
    --primary-hover: #60a5fa;
    --primary-light: #1e293b;
    --accent: #10b981;
    --accent-bg: #064e3b;
    --shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.5);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.5;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

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

/* App Header */
.app-header {
    width: 100%;
    background-color: var(--card-bg);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-container {
    max-width: 680px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.85rem 1.25rem;
}

.brand {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    font-weight: 800;
    font-size: 1.25rem;
    color: var(--text-main);
    text-decoration: none;
}

.brand-icon {
    background: linear-gradient(135deg, var(--primary) 0%, #1d4ed8 100%);
    color: #ffffff;
    width: 36px;
    height: 36px;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    font-weight: 800;
    box-shadow: 0 2px 4px rgba(37, 99, 235, 0.3);
}

/* Header Right Actions */
.header-right-actions {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.header-action-btn {
    background-color: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 0.5rem 0.75rem;
    color: var(--text-main);
    font-weight: 700;
    font-size: 0.85rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.35rem;
    transition: all var(--transition-speed);
}

.header-action-btn:hover {
    background-color: var(--primary-light);
    border-color: var(--primary);
    color: var(--primary);
}

.btn-svg-icon {
    flex-shrink: 0;
    display: block;
}

@media (max-width: 520px) {
    .header-action-btn .btn-text {
        display: none;
    }
}

.theme-btn {
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 0.45rem 0.65rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-main);
    transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

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

/* Main Layout */
.app-main {
    flex: 1;
    width: 100%;
    max-width: 680px;
    padding: 1.5rem 0.85rem;
}

.calculator-card, .page-card {
    background-color: var(--card-bg);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    padding: 1.5rem;
}

@media (max-width: 480px) {
    .calculator-card, .page-card {
        padding: 1.15rem;
    }
}

/* Calculator Integrated Currency Toolbar */
.calc-toolbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background-color: var(--bg-color);
    padding: 0.6rem 0.85rem;
    border-radius: 10px;
    margin-bottom: 1.25rem;
    border: 1px solid var(--border-color);
}

.calc-toolbar-label {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--text-muted);
}

.calc-currency-dropdown {
    padding: 0.4rem 0.65rem;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    background-color: var(--card-bg);
    color: var(--text-main);
    font-size: 0.875rem;
    font-weight: 700;
    cursor: pointer;
}

/* Page Card Content */
.page-card h1 {
    font-size: 1.6rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
    color: var(--text-main);
}

.lead-text {
    font-size: 1.05rem;
    color: var(--text-muted);
    margin-bottom: 1.5rem;
}

.privacy-tagline {
    display: inline-block;
    background-color: var(--accent-bg);
    color: var(--accent);
    padding: 0.5rem 0.85rem;
    border-radius: 8px;
    font-weight: 700;
    font-size: 0.9rem;
    margin-bottom: 1.5rem;
    border: 1px solid var(--accent);
}

.guide-step, .privacy-section {
    margin-bottom: 1.5rem;
}

.guide-step h2, .privacy-section h2 {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text-main);
}

.guide-step p, .privacy-section p {
    font-size: 0.95rem;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
}

.guide-step ol {
    padding-left: 1.25rem;
    font-size: 0.95rem;
    color: var(--text-muted);
}

.guide-step li {
    margin-bottom: 0.5rem;
}

.back-link-wrapper {
    margin-top: 2rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.primary-link-btn {
    display: inline-block;
    padding: 0.75rem 1.25rem;
    background-color: var(--primary);
    color: #ffffff;
    text-decoration: none;
    font-weight: 700;
    border-radius: 8px;
    transition: background-color var(--transition-speed);
}

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

/* Tab Navigation */
.tab-nav {
    display: flex;
    background-color: var(--bg-color);
    padding: 4px;
    border-radius: 12px;
    margin-bottom: 1.25rem;
    gap: 4px;
}

.tab-btn {
    flex: 1;
    padding: 0.8rem 0.5rem;
    border: none;
    background: transparent;
    color: var(--text-muted);
    font-weight: 700;
    font-size: 0.95rem;
    border-radius: 8px;
    cursor: pointer;
    transition: all var(--transition-speed);
}

.tab-btn.active {
    background-color: var(--card-bg);
    color: var(--primary);
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.08);
}

/* Form Controls & High Visibility Hero Inputs */
.tab-panel.hidden,
.input-group.hidden,
.recent-section.hidden,
.result-card.hidden,
.modal-overlay.hidden {
    display: none !important;
}

.input-group {
    margin-bottom: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

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

label {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--text-main);
}

.primary-hero-input label {
    font-size: 1.1rem;
    font-weight: 800;
    color: var(--text-main);
    letter-spacing: 0.01em;
}

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

/* Input Styling */
.input-wrapper input {
    width: 100%;
    padding: 0.85rem 1rem;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-main);
    background-color: var(--input-bg);
    border: 2px solid var(--border-color);
    border-radius: 10px;
    outline: none;
    transition: border-color var(--transition-speed), box-shadow var(--transition-speed);
}

/* HERO Inputs for Shoppers on Mobile */
.input-wrapper.hero input {
    padding: 1.1rem 1.25rem;
    font-size: 1.6rem;
    font-weight: 800;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    background-color: var(--input-bg);
}

.input-wrapper input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.18);
}

.input-wrapper .currency-symbol {
    position: absolute;
    left: 1rem;
    color: var(--text-muted);
    font-weight: 800;
    font-size: 1.25rem;
    pointer-events: none;
}

.input-wrapper.hero .currency-symbol {
    left: 1.25rem;
    font-size: 1.6rem;
}

.input-wrapper .suffix {
    position: absolute;
    right: 1rem;
    color: var(--text-muted);
    font-weight: 800;
    font-size: 1.25rem;
    pointer-events: none;
}

.input-wrapper.hero .suffix {
    right: 1.25rem;
    font-size: 1.6rem;
}

.input-wrapper input:has(+ .suffix) {
    padding-right: 2.75rem;
}

.input-wrapper.hero input:has(+ .suffix) {
    padding-right: 3.25rem;
}

.input-wrapper:has(.currency-symbol) input {
    padding-left: 2.5rem;
}

.input-wrapper.hero:has(.currency-symbol) input {
    padding-left: 3rem;
}

/* Dynamic Recently Used Grid */
.recent-section {
    margin-bottom: 1.5rem;
}

.recent-label {
    display: block;
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--text-muted);
    margin-bottom: 0.6rem;
}

.recent-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
}

.recent-btn {
    padding: 0.55rem 0.95rem;
    border: 1px solid var(--border-color);
    background-color: var(--bg-color);
    color: var(--text-main);
    font-weight: 700;
    font-size: 0.95rem;
    border-radius: 8px;
    cursor: pointer;
    transition: all var(--transition-speed);
}

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

/* Mobile Toggle Switch */
.option-toggle-wrapper {
    margin-bottom: 1.25rem;
}

.toggle-control {
    display: flex;
    align-items: center;
    gap: 0.85rem;
    cursor: pointer;
    user-select: none;
    padding: 0.25rem 0;
}

.toggle-control input[type="checkbox"] {
    position: absolute;
    opacity: 0;
    width: 0;
    height: 0;
}

.toggle-slider {
    position: relative;
    width: 48px;
    height: 26px;
    background-color: var(--border-color);
    border-radius: 26px;
    transition: background-color var(--transition-speed);
    flex-shrink: 0;
}

.toggle-slider::before {
    content: "";
    position: absolute;
    height: 20px;
    width: 20px;
    left: 3px;
    bottom: 3px;
    background-color: #ffffff;
    border-radius: 50%;
    transition: transform var(--transition-speed);
    box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}

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

.toggle-control input:checked + .toggle-slider::before {
    transform: translateX(22px);
}

.toggle-text {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--text-main);
}

/* Results Section */
.results-container {
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 2px dashed var(--border-color);
}

.result-card {
    background-color: var(--bg-color);
    padding: 1.15rem;
    border-radius: 12px;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.result-card.primary {
    background-color: var(--accent-bg);
    border: 2px solid var(--accent);
    margin-bottom: 1rem;
    padding: 1.25rem;
}

.result-card.primary .result-label {
    color: var(--accent);
    font-size: 0.85rem;
    font-weight: 800;
}

.result-card.primary .result-value {
    color: var(--accent);
    font-size: 2.3rem;
    font-weight: 900;
    line-height: 1.1;
}

.result-label {
    font-size: 0.825rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
}

.result-value {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-main);
}

.results-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.75rem;
}

.results-grid.two-col {
    grid-template-columns: 1fr 1fr;
}

.results-grid.single-col {
    grid-template-columns: 1fr;
}

@media (max-width: 580px) {
    .results-grid {
        grid-template-columns: 1fr;
    }
}

/* Pop-Up Modal Overlays */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(15, 23, 42, 0.65);
    backdrop-filter: blur(6px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 1rem;
}

.modal-content {
    background-color: var(--card-bg);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    width: 100%;
    max-width: 480px;
    padding: 1.5rem;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.75rem;
}

.modal-header h2 {
    font-size: 1.3rem;
    font-weight: 800;
    color: var(--text-main);
}

.close-modal-btn {
    background: transparent;
    border: none;
    font-size: 1.75rem;
    font-weight: 800;
    color: var(--text-muted);
    cursor: pointer;
    line-height: 1;
}

.modal-description {
    font-size: 0.95rem;
    color: var(--text-muted);
    margin-bottom: 1.25rem;
}

/* Favorites Modal Instructions */
.modal-body-instructions {
    color: var(--text-main);
}

.modal-body-instructions .device-badge {
    display: inline-block;
    background-color: var(--primary-light);
    color: var(--primary);
    padding: 0.35rem 0.65rem;
    border-radius: 6px;
    font-size: 0.85rem;
    font-weight: 800;
    margin-bottom: 1rem;
}

.modal-body-instructions ol {
    padding-left: 1.25rem;
    margin-bottom: 1rem;
}

.modal-body-instructions li {
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
    color: var(--text-muted);
}

.modal-body-instructions .key-shortcut {
    display: inline-block;
    background-color: var(--bg-color);
    border: 1px solid var(--border-color);
    padding: 0.15rem 0.4rem;
    border-radius: 4px;
    font-family: monospace;
    font-weight: 700;
    color: var(--text-main);
}

/* Social Share Grid & Official Colors */
.share-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.75rem;
}

.share-option {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.6rem;
    padding: 0.85rem;
    border-radius: 10px;
    font-weight: 700;
    font-size: 0.95rem;
    text-decoration: none;
    border: 1px solid var(--border-color);
    background-color: var(--bg-color);
    color: var(--text-main);
    cursor: pointer;
    transition: all var(--transition-speed);
}

.share-option svg {
    flex-shrink: 0;
}

.share-option:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 10px rgba(0,0,0,0.12);
}

.share-option.whatsapp { background-color: #25D366; color: #ffffff; border: none; }
.share-option.facebook { background-color: #1877F2; color: #ffffff; border: none; }
.share-option.twitter { background-color: #000000; color: #ffffff; border: none; }
.share-option.linkedin { background-color: #0A66C2; color: #ffffff; border: none; }
.share-option.email { background-color: #ea4335; color: #ffffff; border: none; }
.share-option.copy-link { background-color: var(--primary); color: #ffffff; border: none; }

/* SEO Content Section */
.seo-content-container {
    margin-top: 2rem;
    padding: 1.5rem;
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    color: var(--text-main);
}

.seo-content-container h1 {
    font-size: 1.35rem;
    margin-bottom: 0.75rem;
    color: var(--text-main);
}

.seo-content-container h2 {
    font-size: 1.1rem;
    margin-top: 1.25rem;
    margin-bottom: 0.5rem;
    color: var(--text-main);
}

.seo-content-container p {
    font-size: 0.925rem;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
}

.seo-content-container ul, .seo-content-container ol {
    padding-left: 1.25rem;
    font-size: 0.925rem;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
}

.seo-content-container li {
    margin-bottom: 0.35rem;
}

/* Footer & Navigation */
.app-footer {
    padding: 1.5rem;
    text-align: center;
    font-size: 0.85rem;
    color: var(--text-muted);
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    align-items: center;
}

.footer-nav {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.footer-nav a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 700;
}

.footer-nav a:hover {
    text-decoration: underline;
}

.footer-separator {
    color: var(--border-color);
}