:root {
    --primary-color: #333333; /* Dark gray for accents and buttons */
    --secondary-color: #666666; /* Medium gray for secondary text */
    --background-color: #FFFFFF; /* White background for cleanliness */
    --text-color: #000000; /* Black text for max readability */
    --border-color: #CCCCCC; /* Light gray borders */
    --success-color: #000000; /* Black for results to keep monochrome */
    --font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; /* Modern system fonts for clean, Grok-like UI */
    --font-size-base: 14px; /* Slightly larger base for better readability */
    --spacing-unit: 1rem; /* Standard spacing for balanced layout */
    --shadow-light: 0 1px 3px rgba(0, 0, 0, 0.08); /* Very subtle shadow */
    --shadow-hover: 0 3px 6px rgba(0, 0, 0, 0.12); /* Light hover effect */
}

/* Reset for consistency across browsers */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

.logo {
    font-size: 16px;
    font-weight: 700;
    color: var(--text-color);
    font-family: var(--font-family);
    text-transform: uppercase;
    letter-spacing: 1px;
    border-bottom: 0.5px solid var(--border-color);
    text-align: right;
    margin-bottom: calc(var(--spacing-unit) * 0.25); /* Minimal bottom margin */
}

/* Body: Wider content, minimal padding, compact text */
body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6; /* Slightly increased for readability */
    color: var(--text-color);
    background-color: var(--background-color);
    max-width: 1200px; /* Wider for spread-out content */
    margin: 0 auto;
    padding: var(--spacing-unit);
}

/* Header: Compact, small H1 close to top, minimal padding */
header {
    text-align: left;
    padding: calc(var(--spacing-unit) * 0.5) 0; /* Very small padding */
    border-bottom: 0.5px solid var(--border-color);
}

header h1 {
    font-size: calc(var(--font-size-base) * 1.5); /* Adjusted for modern feel */
    color: var(--primary-color);
    font-weight: bold;
    margin-bottom: calc(var(--spacing-unit) * 0.25); /* Minimal bottom margin */
}

header p {
    font-size: calc(var(--font-size-base) * 0.9);
    color: var(--secondary-color);
    margin: 0;
}

/* Main: Reduced gaps between elements */
main {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-unit); /* Balanced gaps */
}

.note-alert {
    font-size: calc(var(--font-size-base) * 1);
    color: #FF0000; /* Red for alerts, but to keep B&W, could change to #000000 if strict */
    text-align: center;
    margin: 10px 0;
    padding: 10px;
}

/* Sections: Tight padding, minimal borders */
section {
    padding: var(--spacing-unit);
    border: 0px solid var(--border-color);
    border-radius: 4px; /* Subtle rounding */
    background-color: #F8F8F8; /* Very light gray for slight contrast */
    box-shadow: var(--shadow-light);
    transition: box-shadow 0.2s ease;
    border-bottom: 0.5px solid var(--border-color);
}

section:hover {
    box-shadow: var(--shadow-hover);
}

section h2 {
    font-size: calc(var(--font-size-base) * 1.4);
    color: var(--primary-color);
    margin-bottom: calc(var(--spacing-unit) * 0.5);
    font-weight: bold;
}

section h3 {
    font-size: calc(var(--font-size-base) * 1.1);
    color: var(--secondary-color);
    margin-bottom: calc(var(--spacing-unit) * 0.25);
    font-weight: normal;
    text-decoration: underline;
}

/* Forms: Compact grid, small elements */
form {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
    gap: calc(var(--spacing-unit) * 0.5); /* Reduced gap */
    align-items: center;
}

label {
    font-weight: bold;
    color: var(--secondary-color);
    font-size: calc(var(--font-size-base) * 0.9);
}

input[type="number"] {
    padding: calc(var(--spacing-unit) * 0.4);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: var(--font-size-base);
    background-color: #FFFFFF; /* White input bg */
    color: var(--text-color);
    transition: border-color 0.2s ease;
}

input[type="number"]:focus {
    border-color: var(--primary-color);
    outline: none;
}

button {
    padding: calc(var(--spacing-unit) * 0.4) calc(var(--spacing-unit) * 0.8);
    background-color: var(--primary-color);
    color: #FFFFFF; /* White text on dark gray button */
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: var(--font-size-base);
    transition: background-color 0.2s ease, box-shadow 0.2s ease;
    box-shadow: var(--shadow-light);
}

button:hover {
    background-color: #222222; /* Darker gray on hover */
    box-shadow: var(--shadow-hover);
}

/* Results: Small and highlighted */
span[id$="-result"] {
    font-weight: bold;
    color: var(--success-color);
    font-size: calc(var(--font-size-base) * 1.1);
    margin-left: calc(var(--spacing-unit) * 0.5);
}

/* Canvas: Compact charts */
canvas {
    display: block;
    margin: calc(var(--spacing-unit) * 0.5) auto; /* Reduced margin */
    max-width: 100%;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background-color: #FFFFFF; /* White canvas bg */
}

/* Tables: Tight, striped for readability */
table {
    width: 100%;
    border-collapse: collapse;
    margin: calc(var(--spacing-unit) * 0.5) 0;
}

th, td {
    padding: calc(var(--spacing-unit) * 0.4);
    border: 1px solid var(--border-color);
    text-align: left;
    font-size: calc(var(--font-size-base) * 0.9);
}

th {
    background-color: var(--primary-color);
    color: #FFFFFF;
    font-weight: bold;
}

tr:nth-child(even) {
    background-color: #F0F0F0;
}

tr:hover td {
    background-color: #E0E0E0;
}

/* Lists: Minimal indentation */
ul, ol {
    margin-left: var(--spacing-unit);
    margin-bottom: calc(var(--spacing-unit) * 0.5);
    font-size: calc(var(--font-size-base) * 0.9);
}

/* Links: Simple hover */
a {
    color: var(--primary-color);
    text-decoration: underline;
    transition: color 0.3s ease, text-decoration-color 0.3s ease;
    text-decoration-color: transparent;
    text-decoration: underline;
}

a:hover {
    color: #000000;
    text-decoration-color: currentColor;
}

/* Footer: Compact at bottom */
footer {
    text-align: center;
    padding: calc(var(--spacing-unit) * 0.5);
    border-top: 1px solid var(--border-color);
    margin-top: var(--spacing-unit);
    font-size: calc(var(--font-size-base) * 0.8);
    color: var(--secondary-color);
}

/* Responsive: Adjust for smaller screens */
@media (max-width: 1024px) {
    body {
        max-width: 95%;
        padding: calc(var(--spacing-unit) * 0.5);
    }
    header h1 {
        font-size: calc(var(--font-size-base) * 1.4);
    }
}

@media (max-width: 768px) {
    body {
        padding: calc(var(--spacing-unit) * 0.25);
    }
    form {
        grid-template-columns: 1fr;
    }
    input[type="number"], button {
        width: 100%;
    }
    table {
        font-size: calc(var(--font-size-base) * 0.85);
    }
}

#tool-form {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.currency-section {
    width: 100%;
    max-width: 400px;
    margin-bottom: 20px;
    text-align: center;
}

.sections-container {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    width: 100%;
}

.sections-container-1 {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    width: 100%;
    max-width: 600px;
}

fieldset {
    flex: 1 1 300px;
    margin: 10px;
    padding: 15px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    background-color: #F8F8F8; /* Light fieldset bg */
}

.input-row {
    display: flex;
    align-items: center;
    margin-bottom: 10px;
    position: relative;
}

.input-row label {
    flex: 1;
    margin-right: 10px;
    text-align: right;
}

.input-row input, .input-row select {
    flex: 1;
    background-color: #FFFFFF;
    color: var(--text-color);
    border: 1px solid var(--border-color);
    padding: calc(var(--spacing-unit) * 0.4);
    border-radius: 4px;
}

@media (max-width: 768px) {
    .sections-container {
        flex-direction: column;
    }
    .input-row label {
        text-align: right;
        margin-right: 10px;
        margin-bottom: 0;
    }
    .input-row {
        flex-wrap: wrap;
    }
}

.pdf-button {
    margin: 10px;
    margin-bottom: 20px;
}

.share-button {
    margin: 10px;
    margin-bottom: 20px;
}

.results-section {
    text-align: center;
    font-size: 1.3em;
    color: var(--success-color);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 20px;
    margin: 20px auto;
    max-width: 1200px;
    background-color: #F8F8F8;
    box-shadow: var(--shadow-light);
}

.results-section p {
    margin: 10px 0;
    padding: 10px;
    border-bottom: 1px solid var(--border-color);
}

.results-section p:last-child {
    border-bottom: none;
}

.info-icon {
    margin-left: 3px;
    vertical-align: middle;
    width: 13px;
    height: 13px;
    bottom: 8px;
}

.tooltiptext {
    visibility: hidden;
    width: 220px;
    background-color: #333333;
    color: #FFFFFF;
    text-align: left;
    border-radius: 6px;
    padding: 8px;
    position: absolute;
    z-index: 1;
    top: 120%;
    left: 0;
    opacity: 0;
    transition: opacity 0.3s;
}

.info-icon:hover + .tooltiptext {
    visibility: visible;
    opacity: 1;
}

@media (max-width: 768px) {
    .tooltiptext {
        width: 180px;
        top: 100%;
        left: -50px;
    }
    .info-icon {
        vertical-align: middle;
        margin-left: 3px;
        width: 12px;
        height: 12px;
        bottom: 4px;
    }
}