/* =============================================================================
   Intereses Reales Calculator - Styles
   Brand: ArrendaQ-inspired cyan theme
   ============================================================================= */

/* -----------------------------------------------------------------------------
   CSS Variables / Design Tokens
   ----------------------------------------------------------------------------- */

:root {
    /* Colors - Primary */
    --color-primary: #33c5ff;
    --color-primary-dark: #00a3d9;
    --color-primary-light: #ebf9ff;
    --color-primary-subtle: rgba(51, 197, 255, 0.1);
    --color-primary-border: #d6f3ff;

    /* Colors - Semantic */
    --color-success: #3fca90;
    --color-success-subtle: rgba(63, 202, 144, 0.1);
    --color-danger: #ed5050;
    --color-danger-subtle: rgba(237, 80, 80, 0.1);
    --color-warning: #edcb50;
    --color-warning-subtle: rgba(237, 203, 80, 0.1);

    /* Colors - Neutrals */
    --color-white: #ffffff;
    --color-black: #121519;
    --color-gray-50: #f6f9fc;
    --color-gray-100: #edf1f5;
    --color-gray-200: #dce3eb;
    --color-gray-300: #c5cdd8;
    --color-gray-400: #9ba5b3;
    --color-gray-500: #6b7785;
    --color-gray-600: #576071;
    --color-gray-700: #434a57;
    --color-gray-800: #2d333d;
    --color-gray-900: #1a1e24;

    /* Backgrounds */
    --bg-body: var(--color-gray-50);
    --bg-card: var(--color-white);
    --bg-input: var(--color-white);

    /* Text */
    --text-primary: var(--color-gray-900);
    --text-secondary: var(--color-gray-600);
    --text-muted: var(--color-gray-500);
    --text-inverse: var(--color-white);

    /* Borders */
    --border-color: var(--color-gray-200);
    --border-color-focus: var(--color-primary);

    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    --font-size-4xl: 2.5rem;

    /* Spacing */
    --spacing-1: 0.25rem;
    --spacing-2: 0.5rem;
    --spacing-3: 0.75rem;
    --spacing-4: 1rem;
    --spacing-5: 1.25rem;
    --spacing-6: 1.5rem;
    --spacing-8: 2rem;
    --spacing-10: 2.5rem;
    --spacing-12: 3rem;

    /* Border Radius */
    --radius-sm: 0.5rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-xl: 1.25rem;
    --radius-full: 50rem;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 1px 3px rgba(0, 0, 0, 0.04), 0 6px 16px rgba(0, 0, 0, 0.04);
    --shadow-lg: 0 4px 12px rgba(0, 0, 0, 0.06), 0 12px 28px rgba(0, 0, 0, 0.08);
    --shadow-xl: 0 8px 24px rgba(0, 0, 0, 0.08), 0 24px 48px rgba(0, 0, 0, 0.12);
    --shadow-primary: 0 4px 14px rgba(51, 197, 255, 0.35);

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 200ms ease;
    --transition-slow: 300ms ease;

    /* Z-index */
    --z-dropdown: 100;
    --z-sticky: 200;
    --z-modal: 300;
    --z-toast: 400;
}

/* -----------------------------------------------------------------------------
   Reset & Base
   ----------------------------------------------------------------------------- */

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

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    font-weight: 400;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-body);
    min-height: 100vh;
    overflow-x: hidden;
}

/* -----------------------------------------------------------------------------
   Background Mesh Gradient
   ----------------------------------------------------------------------------- */

.bg-mesh {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: -1;
    background:
        radial-gradient(ellipse at 20% 20%, rgba(51, 197, 255, 0.08) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 80%, rgba(63, 202, 144, 0.06) 0%, transparent 50%),
        radial-gradient(ellipse at 60% 10%, rgba(51, 197, 255, 0.05) 0%, transparent 40%),
        var(--bg-body);
    pointer-events: none;
}

/* -----------------------------------------------------------------------------
   Container & Layout
   ----------------------------------------------------------------------------- */

.container {
    width: 100%;
    max-width: 720px;
    margin: 0 auto;
    padding: var(--spacing-4);
}

@media (min-width: 640px) {
    .container {
        padding: var(--spacing-8);
    }
}

/* -----------------------------------------------------------------------------
   Header
   ----------------------------------------------------------------------------- */

.header {
    margin-bottom: var(--spacing-8);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-4);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
}

.logo-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    border-radius: var(--radius-md);
    color: var(--color-white);
    box-shadow: var(--shadow-primary);
}

.logo-text {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.02em;
}

.badge {
    display: inline-flex;
    align-items: center;
    padding: var(--spacing-2) var(--spacing-3);
    font-size: var(--font-size-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-primary-dark);
    background-color: var(--color-primary-light);
    border-radius: var(--radius-full);
}

/* -----------------------------------------------------------------------------
   Cards
   ----------------------------------------------------------------------------- */

.card {
    background-color: var(--bg-card);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    overflow: hidden;
    margin-bottom: var(--spacing-6);
}

.card-header {
    padding: var(--spacing-6) var(--spacing-6) 0;
}

.card-title {
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-1);
}

.card-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background-color: var(--color-primary-subtle);
    border-radius: var(--radius-md);
    color: var(--color-primary);
}

.card-subtitle {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    margin-left: calc(36px + var(--spacing-3));
}

.card-body {
    padding: var(--spacing-6);
}

/* -----------------------------------------------------------------------------
   Form Elements
   ----------------------------------------------------------------------------- */

.form-section {
    margin-bottom: var(--spacing-6);
}

.form-section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-3);
}

.form-group {
    margin-bottom: var(--spacing-5);
}

.form-label {
    display: block;
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-2);
}

.form-hint {
    display: block;
    font-size: var(--font-size-xs);
    font-weight: 400;
    color: var(--text-muted);
    margin-top: var(--spacing-1);
}

.form-control {
    width: 100%;
    padding: var(--spacing-3) var(--spacing-4);
    font-family: inherit;
    font-size: var(--font-size-base);
    font-weight: 500;
    color: var(--text-primary);
    background-color: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
    appearance: none;
}

.form-control:hover {
    border-color: var(--color-gray-300);
}

.form-control:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(51, 197, 255, 0.15);
}

.form-control::placeholder {
    color: var(--color-gray-400);
    font-weight: 400;
}

/* Input Group */
.input-group {
    display: flex;
    align-items: stretch;
}

.input-group .form-control {
    border-radius: 0;
    flex: 1;
}

.input-group .input-prefix,
.input-group .input-suffix {
    display: flex;
    align-items: center;
    padding: 0 var(--spacing-3);
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--text-muted);
    background-color: var(--color-gray-50);
    border: 1px solid var(--border-color);
}

.input-group .input-prefix {
    border-right: none;
    border-radius: var(--radius-md) 0 0 var(--radius-md);
}

.input-group .input-suffix {
    border-left: none;
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.input-group:focus-within .input-prefix,
.input-group:focus-within .input-suffix {
    border-color: var(--color-primary);
}

.input-group:focus-within .form-control {
    border-color: var(--color-primary);
}

.input-group-sm .form-control {
    padding: var(--spacing-2) var(--spacing-3);
    font-size: var(--font-size-sm);
}

.input-group-sm .input-prefix {
    padding: 0 var(--spacing-2);
    font-size: var(--font-size-xs);
}

/* Select */
select.form-control {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%236b7785' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right var(--spacing-3) center;
    padding-right: var(--spacing-10);
}

/* -----------------------------------------------------------------------------
   Transactions List
   ----------------------------------------------------------------------------- */

.transactions-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-3);
}

.transaction-row {
    display: grid;
    grid-template-columns: 140px 1fr 140px 40px;
    gap: var(--spacing-3);
    align-items: center;
    padding: var(--spacing-3);
    background-color: var(--color-gray-50);
    border-radius: var(--radius-md);
    animation: slideIn 0.2s ease-out;
}

@media (max-width: 640px) {
    .transaction-row {
        grid-template-columns: 1fr 1fr;
        grid-template-rows: auto auto;
    }

    .transaction-date {
        grid-column: 1;
    }

    .transaction-type {
        grid-column: 2;
    }

    .transaction-amount {
        grid-column: 1 / 3;
    }

    .transaction-row .btn-remove-transaction {
        position: absolute;
        right: var(--spacing-2);
        top: var(--spacing-2);
    }

    .transaction-row {
        position: relative;
        padding-right: var(--spacing-10);
    }
}

.transaction-field .form-control {
    padding: var(--spacing-2) var(--spacing-3);
    font-size: var(--font-size-sm);
}

.btn-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border: none;
    background: transparent;
    color: var(--color-gray-400);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: color var(--transition-fast), background-color var(--transition-fast);
}

.btn-icon:hover {
    color: var(--color-danger);
    background-color: var(--color-danger-subtle);
}

/* -----------------------------------------------------------------------------
   Buttons
   ----------------------------------------------------------------------------- */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-2);
    padding: var(--spacing-3) var(--spacing-5);
    font-family: inherit;
    font-size: var(--font-size-sm);
    font-weight: 600;
    text-decoration: none;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.btn-primary {
    color: var(--color-white);
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    box-shadow: var(--shadow-sm), var(--shadow-primary);
}

.btn-primary:hover:not(:disabled) {
    transform: translateY(-1px);
    box-shadow: var(--shadow-md), 0 6px 20px rgba(51, 197, 255, 0.4);
}

.btn-primary:active:not(:disabled) {
    transform: translateY(0);
}

.btn-ghost {
    color: var(--color-primary);
    background: transparent;
    border: 1px solid var(--color-primary-border);
}

.btn-ghost:hover:not(:disabled) {
    background-color: var(--color-primary-subtle);
    border-color: var(--color-primary);
}

.btn-sm {
    padding: var(--spacing-2) var(--spacing-3);
    font-size: var(--font-size-xs);
}

.btn-lg {
    width: 100%;
    padding: var(--spacing-4) var(--spacing-6);
    font-size: var(--font-size-base);
    border-radius: var(--radius-lg);
}

/* Button Loader */
.spinner {
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

/* -----------------------------------------------------------------------------
   Results Section
   ----------------------------------------------------------------------------- */

.card-results {
    border-top: 3px solid var(--color-primary);
}

.result-hero {
    text-align: center;
    padding: var(--spacing-8) var(--spacing-4);
    margin: calc(-1 * var(--spacing-6));
    margin-bottom: var(--spacing-6);
    background: linear-gradient(180deg, var(--color-primary-subtle) 0%, transparent 100%);
}

.result-hero.is-loss {
    background: linear-gradient(180deg, var(--color-danger-subtle) 0%, transparent 100%);
}

.result-label {
    font-size: var(--font-size-xs);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-muted);
    margin-bottom: var(--spacing-2);
}

.result-value {
    font-size: var(--font-size-4xl);
    font-weight: 800;
    color: var(--color-primary);
    letter-spacing: -0.03em;
    line-height: 1.1;
    margin-bottom: var(--spacing-3);
}

.result-hero.is-loss .result-value {
    color: var(--color-danger);
}

.result-badge .badge {
    padding: var(--spacing-2) var(--spacing-4);
    font-size: var(--font-size-sm);
}

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

.badge-warning {
    color: #b8860b;
    background-color: var(--color-warning-subtle);
}

/* ISR Result */
.isr-result {
    background: linear-gradient(135deg, var(--color-gray-50) 0%, var(--color-white) 100%);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-5);
    margin-bottom: var(--spacing-6);
}

.isr-result-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-4);
}

.isr-result-label {
    font-size: var(--font-size-sm);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
}

.isr-result-rate {
    font-size: var(--font-size-xs);
    font-weight: 600;
    color: var(--text-muted);
    background-color: var(--color-gray-100);
    padding: var(--spacing-1) var(--spacing-2);
    border-radius: var(--radius-sm);
}

.isr-result-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-2) 0;
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
}

.isr-result-row span:last-child {
    font-weight: 600;
    color: var(--text-primary);
    font-variant-numeric: tabular-nums;
}

.isr-result-divider {
    height: 1px;
    background-color: var(--border-color);
    margin: var(--spacing-3) 0;
}

.isr-result-total {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-3);
    border-radius: var(--radius-md);
    font-weight: 600;
    transition: background-color var(--transition-fast), color var(--transition-fast);
}

.isr-result-total.is-cargo {
    background-color: var(--color-danger-subtle);
    color: var(--color-danger);
}

.isr-result-total.is-favor {
    background-color: var(--color-success-subtle);
    color: var(--color-success);
}

.isr-total-value {
    font-size: var(--font-size-xl);
    font-weight: 800;
    font-variant-numeric: tabular-nums;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-4);
    margin-bottom: var(--spacing-6);
}

@media (min-width: 480px) {
    .stats-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

.stat-card {
    padding: var(--spacing-4);
    background-color: var(--color-gray-50);
    border-radius: var(--radius-md);
    text-align: center;
}

.stat-label {
    font-size: var(--font-size-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin-bottom: var(--spacing-1);
}

.stat-value {
    font-size: var(--font-size-lg);
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.01em;
}

/* INPC Info */
.inpc-info {
    padding: var(--spacing-4);
    background-color: var(--color-gray-50);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-6);
}

.inpc-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-3);
}

.inpc-values {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-4);
}

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

.inpc-label {
    display: block;
    font-size: var(--font-size-xs);
    color: var(--text-muted);
    margin-bottom: var(--spacing-1);
}

.inpc-value {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--text-primary);
    font-variant-numeric: tabular-nums;
}

.inpc-arrow {
    font-size: var(--font-size-xl);
    color: var(--color-gray-300);
}

/* Formula Box */
.formula-box {
    padding: var(--spacing-4);
    background-color: var(--color-gray-900);
    border-radius: var(--radius-md);
    text-align: center;
}

.formula-title {
    font-size: var(--font-size-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-gray-500);
    margin-bottom: var(--spacing-3);
}

.formula {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
    gap: var(--spacing-2);
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-white);
}

.formula-part {
    padding: var(--spacing-1) var(--spacing-2);
    background-color: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-sm);
}

.formula-equals,
.formula-minus {
    color: var(--color-primary);
    font-weight: 700;
}

/* -----------------------------------------------------------------------------
   Footer
   ----------------------------------------------------------------------------- */

.footer {
    text-align: center;
    padding: var(--spacing-8) var(--spacing-4);
    color: var(--text-muted);
    font-size: var(--font-size-sm);
}

.footer p {
    margin-bottom: var(--spacing-2);
}

.footer-tech {
    font-size: var(--font-size-xs);
    color: var(--color-gray-400);
}

/* -----------------------------------------------------------------------------
   Toast Notifications
   ----------------------------------------------------------------------------- */

.toast {
    position: fixed;
    bottom: var(--spacing-6);
    right: var(--spacing-6);
    left: var(--spacing-6);
    max-width: 400px;
    margin-left: auto;
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-3);
    padding: var(--spacing-4);
    background-color: var(--color-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    z-index: var(--z-toast);
    animation: slideInUp 0.3s ease-out;
}

@media (min-width: 480px) {
    .toast {
        left: auto;
    }
}

.toast-error {
    border-left: 3px solid var(--color-danger);
}

.toast-icon {
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background-color: var(--color-danger-subtle);
    border-radius: var(--radius-md);
    color: var(--color-danger);
}

.toast-content {
    flex: 1;
    min-width: 0;
}

.toast-title {
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-1);
}

.toast-message {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    word-break: break-word;
}

.toast-close {
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    border: none;
    background: transparent;
    color: var(--color-gray-400);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: color var(--transition-fast), background-color var(--transition-fast);
}

.toast-close:hover {
    color: var(--text-primary);
    background-color: var(--color-gray-100);
}

/* -----------------------------------------------------------------------------
   Animations
   ----------------------------------------------------------------------------- */

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-10px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes slideInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-fade-in {
    animation: fadeInUp 0.5s ease-out forwards;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.card-results {
    animation: fadeInUp 0.5s ease-out forwards;
}

/* Staggered animation delays */
.stats-grid .stat-card:nth-child(1) { animation: fadeInUp 0.4s ease-out 0.1s forwards; opacity: 0; }
.stats-grid .stat-card:nth-child(2) { animation: fadeInUp 0.4s ease-out 0.15s forwards; opacity: 0; }
.stats-grid .stat-card:nth-child(3) { animation: fadeInUp 0.4s ease-out 0.2s forwards; opacity: 0; }
.stats-grid .stat-card:nth-child(4) { animation: fadeInUp 0.4s ease-out 0.25s forwards; opacity: 0; }

/* -----------------------------------------------------------------------------
   Utility Classes
   ----------------------------------------------------------------------------- */

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

/* -----------------------------------------------------------------------------
   Explanation Section
   ----------------------------------------------------------------------------- */

.explanation {
    margin-bottom: var(--spacing-6);
}

.explanation-details {
    background-color: var(--bg-card);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    overflow: hidden;
}

.explanation-summary {
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
    padding: var(--spacing-4) var(--spacing-5);
    cursor: pointer;
    font-weight: 600;
    color: var(--text-secondary);
    transition: background-color var(--transition-fast), color var(--transition-fast);
    list-style: none;
}

.explanation-summary::-webkit-details-marker {
    display: none;
}

.explanation-summary:hover {
    background-color: var(--color-gray-50);
    color: var(--text-primary);
}

.explanation-summary .chevron {
    margin-left: auto;
    transition: transform var(--transition-base);
}

.explanation-details[open] .explanation-summary .chevron {
    transform: rotate(180deg);
}

.explanation-content {
    padding: 0 var(--spacing-5) var(--spacing-5);
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
    line-height: 1.7;
}

.explanation-content p {
    margin-bottom: var(--spacing-3);
}

.explanation-content p:last-of-type {
    margin-bottom: var(--spacing-4);
}

.explanation-example {
    background: linear-gradient(135deg, var(--color-primary-subtle) 0%, var(--color-primary-light) 100%);
    border-left: 3px solid var(--color-primary);
    padding: var(--spacing-3) var(--spacing-4);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    font-size: var(--font-size-sm);
}

.explanation-label {
    font-weight: 700;
    color: var(--color-primary-dark);
}

/* -----------------------------------------------------------------------------
   Footer Branding
   ----------------------------------------------------------------------------- */

.footer-brand {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-2);
    margin-bottom: var(--spacing-4);
    padding-bottom: var(--spacing-4);
    border-bottom: 1px solid var(--border-color);
}

.footer-brand-text {
    font-size: var(--font-size-sm);
    color: var(--text-muted);
}

.footer-logo-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
    text-decoration: none;
    transition: opacity var(--transition-fast);
}

.footer-logo-link:hover {
    opacity: 0.8;
}

.footer-logo {
    height: 28px;
    width: auto;
}

.footer-logo-text {
    font-size: var(--font-size-lg);
    font-weight: 700;
    color: var(--text-primary);
}

/* -----------------------------------------------------------------------------
   Results Wrapper with Side Optin
   ----------------------------------------------------------------------------- */

.results-wrapper {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-6);
}

@media (min-width: 900px) {
    .results-wrapper {
        grid-template-columns: 1fr 320px;
        align-items: start;
    }

    .results-wrapper.full-width {
        grid-template-columns: 1fr;
    }
}

/* -----------------------------------------------------------------------------
   Optin Panel (Side)
   ----------------------------------------------------------------------------- */

.optin-panel {
    position: sticky;
    top: var(--spacing-6);
}

.optin-card {
    background: linear-gradient(135deg, var(--bg-card) 0%, var(--color-gray-50) 100%);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--spacing-6);
    box-shadow: var(--shadow-md);
}

.optin-header {
    text-align: center;
    margin-bottom: var(--spacing-5);
}

.optin-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 56px;
    height: 56px;
    background: linear-gradient(135deg, var(--color-primary-light) 0%, var(--color-primary-subtle) 100%);
    border-radius: var(--radius-lg);
    color: var(--color-primary);
    margin-bottom: var(--spacing-3);
}

.optin-title {
    font-size: var(--font-size-lg);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--spacing-1);
}

.optin-subtitle {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    line-height: 1.5;
}

.optin-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-3);
}

.optin-field .form-control {
    text-align: center;
}

.optin-roles {
    display: flex;
    gap: var(--spacing-2);
    justify-content: center;
}

.optin-role {
    cursor: pointer;
    flex: 1;
}

.optin-role input {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}

.optin-role span {
    display: block;
    padding: var(--spacing-2) var(--spacing-3);
    background-color: var(--color-gray-100);
    border: 2px solid transparent;
    border-radius: var(--radius-sm);
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--text-secondary);
    text-align: center;
    transition: all var(--transition-fast);
}

.optin-role input:checked + span {
    background-color: var(--color-primary-light);
    border-color: var(--color-primary);
    color: var(--color-primary-dark);
}

.optin-role span:hover {
    border-color: var(--color-gray-300);
}

.optin-role input:checked + span:hover {
    border-color: var(--color-primary);
}

.optin-submit {
    width: 100%;
}

.optin-privacy {
    text-align: center;
    font-size: var(--font-size-xs);
    color: var(--text-muted);
    margin: 0;
}

/* Optin Success State */
.optin-success {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding: var(--spacing-4) 0;
}

.optin-success-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 64px;
    height: 64px;
    background-color: var(--color-success-subtle);
    border-radius: 50%;
    color: var(--color-success);
    margin-bottom: var(--spacing-3);
    animation: scaleIn 0.3s ease-out;
}

@keyframes scaleIn {
    from {
        transform: scale(0);
        opacity: 0;
    }
    to {
        transform: scale(1);
        opacity: 1;
    }
}

.optin-success-text {
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--color-success);
    margin: 0;
}