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

:root {
    --primary-color: #007AFF;
    --bg-color: #000000;
    --surface-color: #1C1C1E;
    --text-primary: #FFFFFF;
    --text-secondary: #98989D;
    --border-color: #38383A;
    --error-color: #FF3B30;
    --success-color: #34C759;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
    overflow-x: hidden;
}

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

.screen.active {
    display: block;
}

/* Login Screen */
.login-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    padding: 2rem;
    text-align: center;
}

.logo {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 2rem;
    color: white;
}

.login-container h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.subtitle {
    color: var(--text-secondary);
    margin-bottom: 3rem;
    font-size: 1.1rem;
}

.apple-sign-in-button {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    background: #000000;
    color: white;
    border: 1px solid #333;
    border-radius: 8px;
    padding: 12px 24px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    min-width: 240px;
}

.apple-sign-in-button:hover {
    background: #1a1a1a;
    border-color: #555;
}

.apple-sign-in-button:active {
    transform: scale(0.98);
}

.error-message {
    margin-top: 1rem;
    color: var(--error-color);
    font-size: 0.9rem;
    display: none;
}

.error-message.show {
    display: block;
}

/* App Screen */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    background: var(--surface-color);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

header h2 {
    font-size: 1.5rem;
    font-weight: 600;
}

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

.icon-button {
    background: transparent;
    border: none;
    color: var(--text-primary);
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.2s;
}

.icon-button:hover {
    background: var(--border-color);
}

.content {
    padding: 2rem;
    max-width: 1400px;
    margin: 0 auto;
}

/* Loading */
.loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 4rem 2rem;
    color: var(--text-secondary);
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 1rem;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Photo Grid */
.photo-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1rem;
    margin-top: 1rem;
}

.photo-item {
    position: relative;
    aspect-ratio: 1;
    border-radius: 8px;
    overflow: hidden;
    cursor: pointer;
    background: var(--surface-color);
    transition: transform 0.2s;
}

.photo-item:hover {
    transform: scale(1.02);
}

.photo-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.photo-item.loading {
    display: flex;
    align-items: center;
    justify-content: center;
}

.photo-item.loading::after {
    content: '';
    width: 30px;
    height: 30px;
    border: 2px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

/* Empty State */
.empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 4rem 2rem;
    color: var(--text-secondary);
    text-align: center;
}

.empty-state svg {
    margin-bottom: 1rem;
    opacity: 0.5;
}

.empty-state.hidden {
    display: none;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.95);
    z-index: 1000;
    overflow: auto;
}

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

.modal-content {
    position: relative;
    max-width: 90vw;
    max-height: 90vh;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.modal-close {
    position: absolute;
    top: -40px;
    right: 0;
    background: transparent;
    border: none;
    color: white;
    font-size: 2rem;
    cursor: pointer;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1001;
}

.modal-content img {
    max-width: 100%;
    max-height: 80vh;
    object-fit: contain;
    border-radius: 8px;
}

.modal-info {
    margin-top: 1rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
    text-align: center;
}

/* Responsive */
@media (max-width: 768px) {
    .photo-grid {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
        gap: 0.5rem;
    }
    
    header {
        padding: 1rem;
    }
    
    .content {
        padding: 1rem;
    }
}