/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f5f5;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 20px;
    background-color: white;
    min-height: 100vh;
}

/* Header */
header {
    text-align: center;
    padding: 30px 20px;
    border-bottom: 3px solid #2c3e50;
    margin-bottom: 30px;
}

header h1 {
    color: #2c3e50;
    font-size: 2em;
    margin-bottom: 10px;
}

.subtitle {
    color: #7f8c8d;
    font-size: 1.1em;
}

/* Tabs */
.tabs {
    display: flex;
    gap: 10px;
    margin-bottom: 30px;
    border-bottom: 2px solid #ecf0f1;
}

.tab-button {
    padding: 12px 24px;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1em;
    color: #7f8c8d;
    border-bottom: 3px solid transparent;
    transition: all 0.3s;
}

.tab-button:hover {
    color: #2c3e50;
}

.tab-button.active {
    color: #2c3e50;
    border-bottom-color: #3498db;
    font-weight: 600;
}

/* Tab Content */
.tab-content {
    display: none;
}

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

/* Form Sections */
.form-section {
    margin-bottom: 40px;
    padding: 20px;
    background-color: #fafafa;
    border-radius: 8px;
    border-left: 4px solid #3498db;
}

.form-section h2 {
    color: #2c3e50;
    font-size: 1.5em;
    margin-bottom: 10px;
}

.section-description {
    color: #7f8c8d;
    font-size: 0.9em;
    margin-bottom: 20px;
}

.required {
    color: #e74c3c;
}

/* Form Elements */
.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-bottom: 20px;
}

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

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: #2c3e50;
}

.form-group input[type="text"],
.form-group input[type="number"],
.form-group input[type="date"],
.form-group input[type="datetime-local"],
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 1em;
    font-family: inherit;
    transition: border-color 0.3s;
}

.form-group input[type="text"]:focus,
.form-group input[type="number"]:focus,
.form-group input[type="date"]:focus,
.form-group input[type="datetime-local"]:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #3498db;
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

.form-group small {
    display: block;
    margin-top: 5px;
    color: #7f8c8d;
    font-size: 0.85em;
}

.form-group input[readonly] {
    background-color: #ecf0f1;
    cursor: not-allowed;
}

/* Character Counter */
.char-count {
    text-align: right;
    font-weight: 600;
}

/* Checkbox Group */
.checkbox-group {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 10px;
    margin-top: 10px;
}

.checkbox-group label {
    display: flex;
    align-items: center;
    font-weight: normal;
    cursor: pointer;
}

.checkbox-group input[type="checkbox"] {
    margin-right: 8px;
    cursor: pointer;
}

/* Buttons */
.button {
    padding: 12px 24px;
    border: none;
    border-radius: 4px;
    font-size: 1em;
    cursor: pointer;
    transition: all 0.3s;
    font-weight: 600;
}

.button-primary {
    background-color: #3498db;
    color: white;
}

.button-primary:hover {
    background-color: #2980b9;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.button-secondary {
    background-color: #95a5a6;
    color: white;
}

.button-secondary:hover {
    background-color: #7f8c8d;
}

.small-button {
    padding: 6px 12px;
    font-size: 0.85em;
    margin-left: 10px;
    background-color: #ecf0f1;
    border: 1px solid #bdc3c7;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.3s;
}

.small-button:hover {
    background-color: #bdc3c7;
}

/* Form Actions */
.form-actions {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
    margin-top: 30px;
    padding-top: 30px;
    border-top: 2px solid #ecf0f1;
}

/* Validation Result */
.validation-result {
    margin-top: 20px;
    padding: 15px;
    border-radius: 4px;
    display: none;
}

.validation-result.show {
    display: block;
}

.validation-result.success {
    background-color: #d4edda;
    border: 1px solid #c3e6cb;
    color: #155724;
}

.validation-result.error {
    background-color: #f8d7da;
    border: 1px solid #f5c6cb;
    color: #721c24;
}

.validation-result h3 {
    margin-bottom: 10px;
}

.validation-result ul {
    margin-left: 20px;
}

/* Entries List */
.entries-list {
    margin-top: 20px;
}

.entry-card {
    background-color: #fafafa;
    padding: 20px;
    margin-bottom: 15px;
    border-radius: 8px;
    border-left: 4px solid #3498db;
}

.entry-card h3 {
    color: #2c3e50;
    margin-bottom: 10px;
}

.entry-meta {
    color: #7f8c8d;
    font-size: 0.9em;
    margin-bottom: 10px;
}

.entry-summary {
    margin-bottom: 15px;
    line-height: 1.5;
}

.entry-actions {
    display: flex;
    gap: 10px;
}

.entry-actions button {
    padding: 8px 16px;
    font-size: 0.9em;
}

.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: #7f8c8d;
}

.empty-state-icon {
    font-size: 4em;
    margin-bottom: 20px;
}

/* About Content */
#about-tab h3 {
    color: #2c3e50;
    margin-top: 30px;
    margin-bottom: 15px;
}

#about-tab ul, #about-tab ol {
    margin-left: 30px;
    margin-bottom: 20px;
}

#about-tab li {
    margin-bottom: 10px;
}

#about-tab a {
    color: #3498db;
    text-decoration: none;
}

#about-tab a:hover {
    text-decoration: underline;
}

/* Footer */
footer {
    text-align: center;
    padding: 30px 20px;
    color: #7f8c8d;
    font-size: 0.9em;
    background-color: #f5f5f5;
}

footer a {
    color: #3498db;
    text-decoration: none;
}

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

/* Accessibility */
:focus-visible {
    outline: 3px solid #3498db;
    outline-offset: 2px;
}

/* Print Styles */
@media print {
    .tabs, .form-actions, footer {
        display: none;
    }

    .container {
        max-width: 100%;
    }

    .form-section {
        break-inside: avoid;
    }
}