/* ==========================================================================
   Financial Tools Website - Base Styles
   ========================================================================== */

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

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-bg);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* --------------------------------------------------------------------------
   2. CSS Variables
   -------------------------------------------------------------------------- */
:root {
    --color-primary: #1a365d;
    --color-accent: #ed8936;
    --color-bg: #f7fafc;
    --color-white: #ffffff;
    --color-text: #2d3748;
    --color-text-light: #718096;
    --color-border: #e2e8f0;
    --max-width: 1200px;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --transition: 0.2s ease-in-out;
}

/* --------------------------------------------------------------------------
   3. Layout
   -------------------------------------------------------------------------- */
.container {
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1rem;
}

main {
    flex: 1;
    padding: 2rem 0;
}

/* --------------------------------------------------------------------------
   4. Header
   -------------------------------------------------------------------------- */
.header {
    background-color: var(--color-primary);
    color: var(--color-white);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-md);
}

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

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-white);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

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

.nav {
    display: flex;
    gap: 1.5rem;
}

.nav a {
    color: var(--color-white);
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem;
    border-radius: var(--radius-sm);
    transition: color var(--transition), background-color var(--transition);
}

.nav a:hover,
.nav a.active {
    color: var(--color-accent);
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    color: var(--color-white);
    font-size: 1.5rem;
    cursor: pointer;
}

/* --------------------------------------------------------------------------
   5. Ad Placeholder
   -------------------------------------------------------------------------- */
.ad-slot {
    border: 2px dashed var(--color-border);
    border-radius: var(--radius-md);
    padding: 2rem;
    text-align: center;
    color: var(--color-text-light);
    background-color: var(--color-white);
    margin: 1.5rem 0;
    min-height: 90px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.ad-slot span {
    font-size: 0.875rem;
}

/* --------------------------------------------------------------------------
   6. Calculator Card
   -------------------------------------------------------------------------- */
.calculator-card {
    background-color: var(--color-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    padding: 2rem;
    margin-bottom: 2rem;
}

.calculator-card h1 {
    color: var(--color-primary);
    font-size: 1.75rem;
    margin-bottom: 0.5rem;
}

.calculator-card .subtitle {
    color: var(--color-text-light);
    margin-bottom: 1.5rem;
}

/* --------------------------------------------------------------------------
   7. Form Elements
   -------------------------------------------------------------------------- */
.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 1rem;
}

.form-group {
    display: flex;
    flex-direction: column;
}

label {
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: var(--color-text);
    font-size: 0.875rem;
}

input,
select {
    padding: 0.75rem 1rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: 1rem;
    color: var(--color-text);
    background-color: var(--color-white);
    transition: border-color var(--transition), box-shadow var(--transition);
}

input:focus,
select:focus {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px rgba(237, 137, 54, 0.2);
}

input::placeholder {
    color: var(--color-text-light);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: background-color var(--transition), transform var(--transition);
}

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

.btn-primary:hover {
    background-color: #dd6b20;
    transform: translateY(-1px);
}

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

.btn-secondary:hover {
    background-color: #2c5282;
    transform: translateY(-1px);
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

/* --------------------------------------------------------------------------
   7b. Tabs
   -------------------------------------------------------------------------- */
.tabs {
    display: flex;
    gap: 0;
    margin-bottom: 1.5rem;
    border-bottom: 2px solid var(--color-border);
}

.tab-btn {
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 500;
    background: none;
    border: none;
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    cursor: pointer;
    color: var(--color-text-light);
    transition: color var(--transition), border-color var(--transition);
}

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

.tab-btn.active {
    color: var(--color-primary);
    border-bottom-color: var(--color-accent);
}

.tab-content {
    display: none;
}

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

/* --------------------------------------------------------------------------
   8. Result Display
   -------------------------------------------------------------------------- */
.result-box {
    background-color: var(--color-bg);
    border-left: 4px solid var(--color-accent);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    margin-top: 1.5rem;
}

.result-box h3 {
    color: var(--color-text-light);
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.result-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--color-primary);
}

.result-details {
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--color-border);
}

.result-details p {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.5rem;
    font-size: 0.875rem;
}

.result-details span:first-child {
    color: var(--color-text-light);
}

.result-details span:last-child {
    font-weight: 600;
    color: var(--color-text);
}

/* --------------------------------------------------------------------------
   9. Chart Container
   -------------------------------------------------------------------------- */
.chart-container {
    background-color: var(--color-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    padding: 2rem;
    margin-bottom: 2rem;
}

.chart-container h2 {
    color: var(--color-primary);
    font-size: 1.25rem;
    margin-bottom: 1rem;
}

.chart-controls {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
    flex-wrap: wrap;
}

.chart-controls button {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
    background-color: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition);
}

.chart-controls button:hover,
.chart-controls button.active {
    background-color: var(--color-primary);
    color: var(--color-white);
    border-color: var(--color-primary);
}

.chart-wrapper {
    position: relative;
    height: 300px;
}

/* --------------------------------------------------------------------------
   10. Content Section
   -------------------------------------------------------------------------- */
.content-section {
    background-color: var(--color-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    padding: 2rem;
    margin-bottom: 2rem;
}

.content-section h2 {
    color: var(--color-primary);
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.content-section h3 {
    color: var(--color-primary);
    font-size: 1.25rem;
    margin-top: 1.5rem;
    margin-bottom: 0.75rem;
}

.content-section p {
    color: var(--color-text);
    margin-bottom: 1rem;
    line-height: 1.7;
}

.content-section ul,
.content-section ol {
    margin-bottom: 1rem;
    padding-left: 1.5rem;
}

.content-section li {
    margin-bottom: 0.5rem;
    color: var(--color-text);
}

.content-section a {
    color: var(--color-accent);
    text-decoration: none;
    font-weight: 500;
}

.content-section a:hover {
    text-decoration: underline;
}

/* --------------------------------------------------------------------------
   11. Footer
   -------------------------------------------------------------------------- */
.footer {
    background-color: var(--color-primary);
    color: var(--color-white);
    padding: 2rem 0;
    margin-top: auto;
}

.footer .container {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.footer-links {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 1rem;
    flex-wrap: wrap;
    justify-content: center;
}

.footer-links a {
    color: var(--color-white);
    text-decoration: none;
    font-size: 0.875rem;
    transition: color var(--transition);
}

.footer-links a:hover {
    color: var(--color-accent);
}

.footer-copyright {
    font-size: 0.875rem;
    color: rgba(255, 255, 255, 0.7);
}

/* --------------------------------------------------------------------------
   12. Responsive - Mobile (768px and below)
   -------------------------------------------------------------------------- */
@media (max-width: 768px) {
    html {
        font-size: 14px;
    }

    .header .container {
        flex-wrap: wrap;
    }

    .mobile-menu-btn {
        display: block;
    }

    .nav {
        display: none;
        width: 100%;
        flex-direction: column;
        gap: 0;
        margin-top: 1rem;
    }

    .nav.active {
        display: flex;
    }

    .nav a {
        padding: 0.75rem;
        border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    }

    .calculator-card,
    .chart-container,
    .content-section {
        padding: 1.5rem;
    }

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

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

    .result-value {
        font-size: 1.5rem;
    }

    .chart-wrapper {
        height: 250px;
    }

    .footer-links {
        flex-direction: column;
        gap: 0.75rem;
    }
}

/* --------------------------------------------------------------------------
   Utility Classes
   -------------------------------------------------------------------------- */
.text-center {
    text-align: center;
}

.text-right {
    text-align: right;
}

.mb-0 {
    margin-bottom: 0;
}

.mb-1 {
    margin-bottom: 0.5rem;
}

.mb-2 {
    margin-bottom: 1rem;
}

.mb-3 {
    margin-bottom: 1.5rem;
}

.mt-2 {
    margin-top: 1rem;
}

.mt-3 {
    margin-top: 1.5rem;
}

/* --------------------------------------------------------------------------
   13. Tool Grid (Homepage)
   -------------------------------------------------------------------------- */
.tool-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.tool-card {
    display: block;
    background-color: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    text-decoration: none;
    transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

.tool-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-accent);
}

.tool-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.tool-card h2 {
    color: var(--color-primary);
    font-size: 1.125rem;
    margin-bottom: 0.75rem;
}

.tool-card p {
    color: var(--color-text-light);
    font-size: 0.875rem;
    line-height: 1.6;
    margin-bottom: 1rem;
}

.tool-link {
    display: inline-block;
    color: var(--color-accent);
    font-weight: 600;
    font-size: 0.875rem;
}

.tool-card:hover .tool-link {
    text-decoration: underline;
}

@media (max-width: 768px) {
    .tool-grid {
        grid-template-columns: 1fr;
    }
}

.hidden {
    display: none;
}

.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;
}