:root {
    /* Color Palette - Eye Strain Reduction (Soft Dark Mode) */
    --bg-color: #121212;
    --surface-color: #1e1e1e;
    --surface-color-light: #2c2c2c;
    --text-color: #e0e0e0;
    --text-muted: #b0b0b0;
    --link-color: #4da6ff;
    --link-hover: #3a8bff;
    --header-bg: #1f1f1f;
    --footer-bg: #1a1a1a;
    --nav-bg: #1e1e1e;
    --border-color: #333;
    --form-bg: #2c2c2c;
    --form-border: #444;
    --primary-button: #4da6ff;
    --primary-button-hover: #3a8bff;
    --success-color: #4caf50;
    --error-color: #f44336;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

* {
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
    margin: 0;
    padding: 0;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: var(--bg-color);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--surface-color-light);
}

/* Layout Containers */
.app-container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

header#header {
    background-color: var(--header-bg);
    padding: 1rem 2rem;
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow);
}

header#header h1 {
    margin: 0;
    font-size: 1.5rem;
    color: var(--text-color);
}

.main-layout {
    display: flex;
    flex: 1;
}

aside#nav {
    width: 250px;
    background-color: var(--nav-bg);
    border-right: 1px solid var(--border-color);
    padding: 2rem 1rem;
}

main#content {
    flex: 1;
    padding: 2rem;
    overflow-x: hidden;
}

footer#footer {
    background-color: var(--footer-bg);
    padding: 1.5rem 2rem;
    text-align: center;
    border-top: 1px solid var(--border-color);
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* Legacy Table Support (during transition) */
table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 1rem;
}

th, td {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    text-align: left;
}

tr:nth-child(even) {
    background-color: rgba(255, 255, 255, 0.02);
}

thead th {
    background-color: var(--surface-color-light);
    color: var(--link-color);
    font-weight: 600;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    margin-top: 0;
    margin-bottom: 1rem;
    font-weight: 600;
}

a {
    color: var(--link-color);
    text-decoration: none;
    transition: color 0.2s ease;
}

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

/* Navigation */
nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

nav ul li {
    margin-bottom: 0.5rem;
}

nav ul li a {
    display: block;
    padding: 0.75rem 1rem;
    border-radius: 4px;
    color: var(--text-color);
}

nav ul li a:hover {
    background-color: var(--surface-color-light);
    text-decoration: none;
}

/* Grid System */
.link-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.link-section {
    background-color: var(--surface-color);
    border: 1px solid var(--border-color);
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: var(--shadow);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.link-section:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.4);
}

.link-section h3 {
    margin-top: 0;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.75rem;
    margin-bottom: 1rem;
    color: var(--link-color);
}

.link-section ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.link-section li {
    margin-bottom: 0.75rem;
}

/* Forms */
form {
    margin-bottom: 1.5rem;
}

.upload-form {
    max-width: 500px;
    margin: 2rem auto;
    background-color: var(--surface-color);
    padding: 2rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    box-shadow: var(--shadow);
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

input[type="text"],
input[type="password"],
input[type="date"],
input[type="file"],
select,
textarea {
    width: 100%;
    padding: 0.75rem;
    margin-bottom: 1rem;
    background-color: var(--form-bg);
    color: var(--text-color);
    border: 1px solid var(--form-border);
    border-radius: 4px;
    font-size: 1rem;
}

input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: var(--link-color);
}

input[type="submit"], button, .btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    background-color: var(--primary-button);
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-weight: 600;
    transition: background-color 0.2s ease;
}

input[type="submit"]:hover, button:hover, .btn:hover {
    background-color: var(--primary-button-hover);
}

/* Status Messages */
.error-message, .success-message {
    padding: 1rem;
    border-radius: 4px;
    margin-bottom: 1.5rem;
}

.error-message {
    background-color: rgba(244, 67, 54, 0.1);
    color: var(--error-color);
    border: 1px solid var(--error-color);
}

.success-message {
    background-color: rgba(76, 175, 80, 0.1);
    color: var(--success-color);
    border: 1px solid var(--success-color);
}

/* Responsive */
@media screen and (max-width: 768px) {
    .main-layout {
        flex-direction: column;
    }

    aside#nav {
        width: 100%;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
        padding: 1rem;
    }

    main#content {
        padding: 1rem;
    }

    .link-grid {
        grid-template-columns: 1fr;
    }
}