:root {
    --bg-primary: #0a0a0a;
    --bg-secondary: #1a1a1a;
    --bg-tertiary: #2a2a2a;
    --text-primary: #e0e0e0;
    --text-secondary: #a0a0a0;
    --accent: #4a9eff;
    --accent-hover: #357abd;
    --success: #4caf50;
    --danger: #f44336;
    --border: #333;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

.screen {
    display: none;
    min-height: 100vh;
}

.screen.active {
    display: block;
}

#login-screen.active {
    display: flex;
    align-items: center;
    justify-content: center;
}

#main-screen.active {
    display: block;
}

.container {
    max-width: 600px;
    margin: 0 auto;
    padding: 1rem;
}

#login-screen h1 {
    text-align: center;
    margin-bottom: 2rem;
    font-size: 2.5rem;
}

#login-form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

input, button {
    padding: 0.75rem 1rem;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 1rem;
    background: var(--bg-secondary);
    color: var(--text-primary);
}

input:focus {
    outline: none;
    border-color: var(--accent);
}

button {
    background: var(--accent);
    color: white;
    cursor: pointer;
    font-weight: 600;
    transition: background 0.2s;
}

button:hover {
    background: var(--accent-hover);
}

/* Main Screen */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

header h1 {
    font-size: 1.75rem;
}

.header-actions {
    display: flex;
    gap: 0.5rem;
}

.icon-btn {
    width: 40px;
    height: 40px;
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
}

.date-display {
    text-align: center;
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
    color: var(--text-secondary);
}

.add-exercise {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 2rem;
}

#new-exercise {
    flex: 1;
}

#add-exercise-btn {
    width: 50px;
    font-size: 1.5rem;
    padding: 0;
}

/* Exercise List */
.exercises-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.exercise-item {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1rem;
    cursor: pointer;
    transition: all 0.2s;
}

.exercise-item:hover {
    background: var(--bg-tertiary);
    transform: translateY(-2px);
}

.exercise-name {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.exercise-info {
    display: flex;
    gap: 1rem;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.exercise-info span {
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.8);
    z-index: 1000;
    padding: 1rem;
}

.modal.active {
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-content {
    background: var(--bg-secondary);
    border-radius: 12px;
    padding: 2rem;
    width: 100%;
    max-width: 400px;
}

.modal-content h2 {
    margin-bottom: 1.5rem;
    text-align: center;
}

.form-group {
    margin-bottom: 1.5rem;
}

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

.form-group small {
    display: block;
    margin-top: 0.25rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

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

.form-actions button {
    flex: 1;
}

#cancel-entry {
    background: var(--bg-tertiary);
}

#cancel-entry:hover {
    background: var(--border);
}

/* Responsive */
@media (max-width: 480px) {
    .container {
        padding: 0.75rem;
    }
    
    header h1 {
        font-size: 1.5rem;
    }
    
    .icon-btn {
        width: 36px;
        height: 36px;
        font-size: 1rem;
    }
}