:root {
    /* Colors */
    --primary-color: #0066cc;
    --secondary-color: #333;
    --accent-color: #00aaff;
    --background-color: #f9f9f9;
    --dark-background: #1e1e1e;
    --light-text: #ffffff;
    --dark-text: #333333;
    --border-color: #e0e0e0;
    --card-background: #ffffff;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --pin-color: #ff4444;

    /* Spacing */
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;

    /* Border radius */
    --border-radius: 8px;
}

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

html, body {
    height: 100%;
    min-height: 100%; /* Ensure body takes full height */
    width: 100%;
    overflow: hidden;
    font-family: 'Roboto', sans-serif;
    background-color: var(--background-color);
    color: var(--dark-text);
    line-height: 1.6;
    touch-action: none; /* Prevent default touch behaviors */
}

/* ========== SHARED COMPONENTS ========== */

.app-container {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    flex-direction: column;
    height: var(--app-height, 100dvh); /* Use dynamic viewport height or fallback */
    width: 100%;
    overflow: hidden;
}

.view {
    display: flex;
    flex-direction: column;
    flex: 1;
    min-height: 0; /* Important for Firefox */
    overflow: hidden;
}

#mainView {
    display: flex;
    flex-direction: column;
    height: 100%; /* Take full height of parent */
    width: 100%;
    position: relative;
}

header {
    background-color: var(--card-background);
    color: var(--dark-text);
    padding: var(--spacing-sm) var(--spacing-md);
    box-shadow: 0 1px 4px var(--shadow-color);
    text-align: center;
    flex-shrink: 0;
}

header h1 {
    font-size: 1.2rem;
    margin: 0;
    color: var(--primary-color);
    font-weight: 500;
}

header p {
    opacity: 0.9;
    font-size: 0.85rem;
    margin: 0.2rem 0 0 0;
}

.subtitle {
    opacity: 0.8;
    font-size: 0.9rem;
    margin-top: 0.3rem;
}

button, .btn {
    background-color: var(--primary-color);
    color: var(--light-text);
    border: none;
    border-radius: 6px;
    padding: 0.7rem 1.2rem;
    font-size: 1rem;
    font-family: 'Roboto', sans-serif;
    cursor: pointer;
    transition: all 0.2s;
    font-weight: 500;
    touch-action: manipulation;
}

button:hover, .btn:hover {
    background-color: var(--accent-color);
    transform: translateY(-1px);
    box-shadow: 0 4px 8px var(--shadow-color);
}

button:active, .btn:active {
    transform: translateY(0);
}

button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

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

.btn-danger {
    background-color: #dc3545;
}

.btn-small {
    padding: 0.4rem 0.8rem;
    font-size: 0.9rem;
}

/* ========== SETUP PAGE ========== */

.setup-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    padding: var(--spacing-md);
    gap: var(--spacing-md);
    overflow-y: auto;
}

.upload-section {
    background-color: var(--card-background);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    box-shadow: 0 2px 8px var(--shadow-color);
}

.upload-section h2 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
    font-size: 1.3rem;
}

.file-input-wrapper {
    position: relative;
    display: inline-block;
    width: 100%;
}

.file-input-wrapper input[type="file"] {
    position: absolute;
    opacity: 0;
    width: 100%;
    height: 100%;
    cursor: pointer;
}

.file-input-label {
    display: block;
    padding: var(--spacing-lg);
    background-color: var(--background-color);
    border: 2px dashed var(--primary-color);
    border-radius: var(--border-radius);
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
}

.file-input-label:hover {
    background-color: rgba(0, 102, 204, 0.05);
    border-color: var(--accent-color);
}

.layers-preview {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.layer-card {
    background-color: var(--card-background);
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: var(--spacing-md);
    box-shadow: 0 2px 4px var(--shadow-color);
}

.layer-preview-image {
    width: 100%;
    height: 150px;
    object-fit: contain;
    background-color: #f5f5f5;
    border-radius: var(--border-radius);
    margin-bottom: var(--spacing-sm);
}

.layer-card input[type="text"] {
    width: 100%;
    padding: var(--spacing-sm);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-family: 'Roboto', sans-serif;
    font-size: 0.9rem;
    margin-bottom: var(--spacing-sm);
}

.layer-controls {
    display: flex;
    gap: var(--spacing-sm);
}

.layer-controls button {
    flex: 1;
}

.setup-actions {
    display: flex;
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.setup-actions button {
    flex: 1;
}

/* ========== MAIN APP PAGE ========== */

.main-container {
    flex: 1 1 auto;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    min-height: 0; /* Allow flex child to shrink */
}

.layer-title {
    background-color: var(--background-color);
    padding: 0.3rem var(--spacing-md);
    text-align: center;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--primary-color);
    border-bottom: 1px solid var(--border-color);
    flex-shrink: 0;
}

.canvas-container {
    flex: 1 1 auto;
    position: relative;
    background-color: #f5f5f5;
    overflow: hidden;
    touch-action: none;
    min-height: 0; /* Important for flex children */
    display: flex; /* Make it a flex container */
}

#mainCanvas {
    display: block;
    width: 100%;
    height: 100%;
    touch-action: none;
    cursor: crosshair;
    flex: 1; /* Let canvas fill its container */
}

/* Bottom Controls */
.controls-bar {
    background-color: var(--card-background);
    padding: var(--spacing-sm);
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    border-top: 1px solid var(--border-color);
    z-index: 100;
    flex-shrink: 0; /* Prevent shrinking */
}

.layer-buttons {
    display: flex;
    gap: 0.3rem;
    flex-wrap: wrap;
}

.layer-btn {
    min-width: 40px;
    height: 40px;
    padding: 0.3rem;
    font-weight: 600;
    font-size: 1rem;
    border: 1px solid var(--border-color);
}

.layer-btn.active {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
    color: var(--light-text);
}

.control-buttons {
    display: flex;
    gap: 0.3rem;
}

.fit-btn, .rotate-btn, .settings-btn {
    width: 40px;
    height: 40px;
    padding: 0.3rem;
    font-size: 1.1rem;
    border: 1px solid var(--border-color);
    background-color: var(--card-background);
    color: var(--dark-text);
}

/* Settings/Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.7);
    z-index: 2000;
    align-items: center;
    justify-content: center;
}

.modal.active {
    display: flex;
}

.modal-content {
    background-color: var(--card-background);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    max-width: 400px;
    width: 90%;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.3);
}

.modal-content h2 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
}

.modal-buttons {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}

.modal-buttons button {
    flex: 1;
}

/* Info Messages */
.info-message {
    background-color: rgba(0, 170, 255, 0.1);
    border-left: 4px solid var(--accent-color);
    padding: var(--spacing-md);
    border-radius: 4px;
    margin-bottom: var(--spacing-md);
}

.warning-message {
    background-color: rgba(255, 193, 7, 0.1);
    border-left: 4px solid #ffc107;
    padding: var(--spacing-md);
    border-radius: 4px;
    margin-bottom: var(--spacing-md);
}

/* ========== RESPONSIVE ========== */

@media (max-width: 768px) {
    header h1 {
        font-size: 1.1rem;
    }

    header p {
        font-size: 0.8rem;
    }

    .layers-preview {
        grid-template-columns: 1fr;
    }

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

    .controls-bar {
        padding: 0.4rem;
    }

    .layer-btn {
        min-width: 38px;
        height: 38px;
        font-size: 0.95rem;
    }

    .fit-btn, .rotate-btn, .settings-btn {
        width: 38px;
        height: 38px;
        font-size: 1rem;
    }

    .layer-title {
        font-size: 0.85rem;
        padding: 0.25rem var(--spacing-sm);
    }

    #mainView {
        /* padding-bottom: 55px; */ /* Smaller space for mobile controls */
    }
}

@media (max-width: 480px) {
    button, .btn {
        padding: 0.6rem 1rem;
        font-size: 0.9rem;
    }

    .layer-btn {
        min-width: 36px;
        height: 36px;
        font-size: 0.9rem;
    }

    .fit-btn, .rotate-btn, .settings-btn {
        width: 36px;
        height: 36px;
        font-size: 0.95rem;
    }

    #mainView {
        /* padding-bottom: 50px; */ /* Even smaller space for small mobile */
    }
}

/* ========== LOADING SPINNER ========== */

.spinner {
    border: 3px solid var(--border-color);
    border-top: 3px solid var(--primary-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: 20px auto;
}

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

.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 3000;
}

.loading-overlay.active {
    display: flex;
}