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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

.screen {
    min-height: 100vh;
}

.hidden {
    display: none !important;
}

/* Login Screen */
.login-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    color: white;
    text-align: center;
    padding: 20px;
}

.login-container h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.login-container p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

/* Main Screen */
header {
    background: white;
    padding: 1.5rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

header h1 {
    color: #667eea;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 1rem;
}

main {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 2rem;
}

.add-note-section {
    background: white;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.1);
    margin-bottom: 2rem;
}

.add-note-section h2 {
    color: #333;
    margin-bottom: 1rem;
}

input[type="text"],
textarea {
    width: 100%;
    padding: 0.75rem;
    margin-bottom: 1rem;
    border: 2px solid #e0e0e0;
    border-radius: 5px;
    font-size: 1rem;
    font-family: inherit;
}

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

input:focus,
textarea:focus {
    outline: none;
    border-color: #667eea;
}

/* Buttons */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 5px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-primary {
    background: #667eea;
    color: white;
}

.btn-primary:hover {
    background: #5568d3;
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.btn-secondary {
    background: #f0f0f0;
    color: #333;
}

.btn-secondary:hover {
    background: #e0e0e0;
}

.btn-icon {
    background: none;
    border: none;
    font-size: 1.2rem;
    cursor: pointer;
    padding: 0.25rem 0.5rem;
    transition: transform 0.2s;
}

.btn-icon:hover {
    transform: scale(1.2);
}

.btn-icon.delete:hover {
    color: #e74c3c;
}

/* Notes Section */
.notes-section h2 {
    color: white;
    margin-bottom: 1rem;
}

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

.note-card {
    background: white;
    padding: 1.5rem;
    border-radius: 10px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.note-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px rgba(0,0,0,0.15);
}

.note-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.75rem;
}

.note-header h3 {
    color: #333;
    font-size: 1.25rem;
}

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

.note-card p {
    color: #666;
    line-height: 1.6;
}

.empty-state {
    color: white;
    font-size: 1.1rem;
    text-align: center;
    padding: 2rem;
    opacity: 0.8;
}