:root {
    --primary-color: #007bff;
    --primary-hover: #0056b3;
    --error-color: #dc3545;
    --success-color: #28a745;
    --background-color: #f8f9fa;
    --text-color: #212529;
    --border-color: #dee2e6;
    --spacing-unit: 1rem;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen,
        Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background-color);
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: var(--spacing-unit);
}

header {
    text-align: center;
    margin-bottom: calc(var(--spacing-unit) * 2);
    padding: var(--spacing-unit);
    border-bottom: 2px solid var(--border-color);
}

.workout-form {
    background: white;
    padding: calc(var(--spacing-unit) * 2);
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

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

label {
    display: block;
    margin-bottom: calc(var(--spacing-unit) * 0.5);
    font-weight: 500;
}

input {
    width: 100%;
    padding: calc(var(--spacing-unit) * 0.75);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 1rem;
}

.help-text {
    display: block;
    margin-top: calc(var(--spacing-unit) * 0.25);
    color: #6c757d;
    font-size: 0.875rem;
}

.button {
    display: inline-block;
    padding: calc(var(--spacing-unit) * 0.75) var(--spacing-unit);
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
}

.button:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

.primary {
    background-color: var(--primary-color);
    color: white;
    width: 100%;
}

.primary:hover:not(:disabled) {
    background-color: var(--primary-hover);
}

.secondary {
    background-color: #6c757d;
    color: white;
}

.secondary:hover:not(:disabled) {
    background-color: #5a6268;
}

.loading-spinner {
    text-align: center;
    margin: var(--spacing-unit) 0;
}

.spinner {
    border: 4px solid #f3f3f3;
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: 0 auto;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.workout-display {
    margin-top: calc(var(--spacing-unit) * 2);
    background: white;
    padding: calc(var(--spacing-unit) * 2);
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.markdown-content {
    margin: var(--spacing-unit) 0;
    padding: var(--spacing-unit);
    background-color: #f8f9fa;
    border-radius: 4px;
    white-space: pre-wrap;
    font-family: monospace;
    font-size: 14px;
    line-height: 1.4;
    overflow-x: auto;
}

.error-message {
    padding: var(--spacing-unit);
    margin: var(--spacing-unit) 0;
    background-color: #fff3f3;
    border: 1px solid var(--error-color);
    border-radius: 4px;
    color: var(--error-color);
}

.tooltip {
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--success-color);
    color: white;
    padding: 8px 16px;
    border-radius: 4px;
    animation: fadeInOut 2s ease-in-out;
}

@keyframes fadeInOut {
    0%, 100% { opacity: 0; }
    10%, 90% { opacity: 1; }
}

.hidden {
    display: none;
}

/* Mobile Optimizations */
@media (max-width: 768px) {
    .container {
        padding: calc(var(--spacing-unit) * 0.5);
    }

    .workout-form,
    .workout-display {
        padding: var(--spacing-unit);
    }

    input,
    .button {
        font-size: 16px; /* Prevents iOS zoom on focus */
        padding: 12px;
    }

    .markdown-content {
        font-size: 12px;
        padding: calc(var(--spacing-unit) * 0.75);
    }
}