:root {
    --primary-color: #2563eb;
    --secondary-color: #64748b;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --text-color: #1f2937;
    --text-light: #6b7280;
    --bg-color: #f9fafb;
    --border-color: #e5e7eb;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
}

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

html, body {
    height: 100%;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    color: var(--text-color);
    background-color: var(--bg-color);
    display: flex;
    flex-direction: column;
}

.navbar {
    background-color: white;
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
}

.brand {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

.nav-links {
    display: flex;
    gap: 2rem;
    list-style: none;
    align-items: center;
}

.nav-links a {
    color: var(--text-color);
    text-decoration: none;
    transition: color 0.3s;
    font-weight: 500;
}

.nav-links a:hover {
    color: var(--primary-color);
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.current-user {
    color: var(--text-light);
    font-size: 0.875rem;
    font-weight: 600;
    padding: 0.5rem 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 999px;
    background: #f8fafc;
}

.container {
    flex: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
    width: 100%;
}

.page-header {
    margin-bottom: 2rem;
}

.page-header h2 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.page-header p {
    color: var(--text-light);
    font-size: 1rem;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    text-decoration: none;
    font-weight: 600;
    border: none;
    cursor: pointer;
    transition: all 0.3s;
    text-align: center;
}

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

.btn-primary:hover {
    background-color: #1d4ed8;
    transform: translateY(-2px);
}

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

.btn-secondary:hover {
    background-color: #475569;
}

.btn-edit {
    background-color: var(--primary-color);
    color: white;
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-edit:hover {
    background-color: #1d4ed8;
}

.btn-delete {
    background-color: var(--danger-color);
    color: white;
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-delete:hover {
    background-color: #dc2626;
}

/* Workouts Grid */
.workouts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.workout-card {
    background: white;
    border-radius: 0.75rem;
    box-shadow: var(--shadow);
    padding: 1.5rem;
    transition: all 0.3s;
}

.workout-card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-4px);
}

.workout-header {
    display: flex;
    justify-content: space-between;
    align-items: start;
    margin-bottom: 1rem;
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 1rem;
}

.workout-header h3 {
    font-size: 1.25rem;
    color: var(--primary-color);
    flex: 1;
}

.date {
    font-size: 0.875rem;
    color: var(--text-light);
    white-space: nowrap;
    margin-left: 1rem;
}

.workout-details {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin-bottom: 1rem;
}

.detail-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem;
    background-color: var(--bg-color);
    border-radius: 0.375rem;
}

.detail-item .label {
    font-weight: 600;
    color: var(--text-light);
    font-size: 0.875rem;
}

.detail-item .value {
    font-weight: bold;
    color: var(--primary-color);
    font-size: 1rem;
}

.notes {
    background-color: #fef3c7;
    border-left: 4px solid var(--warning-color);
    padding: 1rem;
    margin: 1rem 0;
    border-radius: 0.375rem;
    font-size: 0.875rem;
}

.workout-actions {
    display: flex;
    gap: 0.75rem;
    margin-top: 1rem;
}

.workout-actions .btn {
    flex: 1;
    text-align: center;
}

/* Form Styles */
.form-container {
    background: white;
    padding: 2rem;
    border-radius: 0.75rem;
    box-shadow: var(--shadow);
    max-width: 600px;
    margin: 0 auto;
}

.workout-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

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

.form-group label {
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.form-group input,
.form-group textarea,
.form-group select {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 0.375rem;
    font-size: 1rem;
    font-family: inherit;
    transition: border-color 0.3s;
    background-color: white;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

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

.form-actions {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

.form-actions .btn {
    flex: 1;
}

/* Login Page */
.login-page {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: calc(100vh - 220px);
    padding: 2rem 0;
}

.login-card {
    width: 100%;
    max-width: 480px;
    background: white;
    border-radius: 1rem;
    padding: 2rem;
    box-shadow: var(--shadow-lg);
}

.login-header {
    margin-bottom: 1.5rem;
}

.login-header h2 {
    font-size: 1.75rem;
    margin-bottom: 0.5rem;
}

.login-header p {
    color: var(--text-light);
}

.login-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.form-info {
    background-color: var(--bg-color);
    padding: 1rem;
    border-radius: 0.375rem;
    border-left: 4px solid var(--secondary-color);
    font-size: 0.875rem;
}

/* Alert Messages */
.alert {
    padding: 1rem;
    border-radius: 0.375rem;
    margin-bottom: 1.5rem;
}

.alert-error {
    background-color: #fee2e2;
    border-left: 4px solid var(--danger-color);
    color: #991b1b;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 3rem 2rem;
    color: var(--text-light);
}

.empty-state a {
    color: var(--primary-color);
    font-weight: 600;
    text-decoration: none;
}

.empty-state a:hover {
    text-decoration: underline;
}

/* Statistics */
.stats-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.stat-card {
    background: white;
    padding: 2rem;
    border-radius: 0.75rem;
    box-shadow: var(--shadow);
    text-align: center;
}

.main-stat {
    border-top: 4px solid var(--primary-color);
}

.stat-card h3 {
    color: var(--text-light);
    margin-bottom: 1rem;
    font-size: 1rem;
}

.stat-value {
    font-size: 2.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

.stat-subtext {
    display: block;
    font-size: 0.875rem;
    color: var(--text-light);
    margin-top: 0.5rem;
}

.exercises-stats {
    background: white;
    padding: 2rem;
    border-radius: 0.75rem;
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
}

.exercises-stats h3 {
    margin-bottom: 1.5rem;
    color: var(--primary-color);
}

.exercises-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.exercise-stat-card {
    background-color: var(--bg-color);
    padding: 1.5rem;
    border-radius: 0.5rem;
    border-left: 4px solid var(--primary-color);
}

.exercise-stat-card h4 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.stat-line {
    display: flex;
    justify-content: space-between;
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

.stat-line:last-child {
    border-bottom: none;
}

.stat-label {
    font-weight: 600;
    color: var(--text-light);
}

.back-link {
    text-align: center;
    margin-top: 2rem;
}

/* Footer */
.footer {
    background-color: white;
    border-top: 1px solid var(--border-color);
    padding: 2rem;
    text-align: center;
    color: var(--text-light);
    margin-top: auto;
}

/* Responsive Design */
@media (max-width: 768px) {
    .navbar .container {
        flex-direction: column;
        gap: 1rem;
    }

    .nav-links {
        width: 100%;
        justify-content: center;
        gap: 1rem;
    }

    .container {
        padding: 1rem;
    }

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

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

    .workout-header {
        flex-direction: column;
        gap: 0.5rem;
    }

    .date {
        margin-left: 0;
    }

    .stats-container {
        grid-template-columns: 1fr;
    }

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

    .form-actions {
        flex-direction: column;
    }

    .page-header h2 {
        font-size: 1.5rem;
    }
}

@media (max-width: 480px) {
    .workout-details {
        grid-template-columns: 1fr;
    }

    .stat-value {
        font-size: 2rem;
    }

    .btn {
        padding: 0.5rem 1rem;
        font-size: 0.875rem;
    }
}