:root {
    --bg-body: #f8fafc;
    --card-bg: #ffffff;
    --text-main: #0f172a;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --accent-color: #4f46e5;
    --accent-hover: #4338ca;
    --header-bg: var(--bg-body);
    --header-text: var(--text-main);
    --header-border: var(--border-color);
}

[data-bs-theme="dark"] {
    --bg-body: #0f172a;
    --card-bg: #1e293b;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --border-color: #334155;
    --accent-color: #312e81; /* Very dark Indigo for dark theme */
    --accent-hover: #1e1b4b;
    --header-bg: #1e293b;
    --header-text: #f8fafc;
    --header-border: rgba(255, 255, 255, 0.1);
}

body {
    background-color: var(--bg-body);
    color: var(--text-main);
    font-family: 'Roboto', sans-serif;
    transition: background-color 0.3s ease, color 0.3s ease;
    margin: 0;
    padding: 0;
}

.app-header {
    background-color: var(--header-bg);
    color: var(--header-text);
    padding: 1.25rem 1rem;
    position: relative;
    border-bottom: 1px solid var(--header-border);
    box-shadow: none;
}

.app-header h1 {
    font-size: 1.35rem !important;
    font-weight: 500;
    margin: 0;
}

.app-header p {
    color: var(--header-text) !important;
    font-size: 0.875rem;
    opacity: 0.8;
    margin: 0.25rem 0 0;
}

.header-content {
    max-width: 1400px;
    margin: 0 auto;
    position: relative;
}

[data-bs-theme="dark"] .app-header {
    border-bottom: 1px solid var(--border-color);
}

/* Theme Toggle Fab */
.theme-fab {
    position: absolute;
    top: 1rem;
    right: 1rem;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: none;
    background: rgba(255, 255, 255, 0.2);
    color: white;
    cursor: pointer;
    font-size: 1.2rem;
    z-index: 20;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(4px);
}

.theme-fab:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: scale(1.05);
}

/* Cards */
.card-custom {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 1rem;
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px -1px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    transition: box-shadow 0.3s ease, border-color 0.3s ease;
}

.card-custom:hover {
    border-color: var(--accent-color);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
}

/* Drop Zone */
.drop-zone {
    border: 2px dashed var(--border-color);
    border-radius: 1rem;
    padding: 4rem 1rem;
    text-align: center;
    background-color: var(--bg-body);
    transition: all 0.3s ease;
    cursor: pointer;
}

.drop-zone.drag-active {
    border-color: var(--accent-color);
    background-color: rgba(79, 70, 229, 0.05);
}

.drop-icon-wrapper i {
    color: var(--accent-color);
}

/* Info Card */
.info-card {
    background-color: var(--bg-body);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: 1.25rem;
}

/* Format Picker */
.format-picker {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1rem;
}

.format-option input {
    position: absolute;
    opacity: 0;
}

.format-card {
    display: block;
    height: 100%;
    padding: 1.25rem;
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    background: var(--card-bg);
    cursor: pointer;
    transition: all 0.2s ease;
}

.format-card:hover {
    border-color: var(--accent-color);
}

.format-option input:checked + .format-card {
    border-color: var(--accent-color);
    background-color: rgba(79, 70, 229, 0.05);
}

[data-bs-theme="dark"] .format-option input:checked + .format-card {
    background-color: rgba(79, 70, 229, 0.15);
}

.format-card-title {
    display: block;
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: 0.25rem;
}

.format-card-copy {
    display: block;
    color: var(--text-muted);
    font-size: 0.875rem;
}

/* Buttons */
.btn-primary {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
    border-radius: 0.5rem;
    font-weight: 500;
    transition: all 0.2s;
    color: white !important;
}

.btn-primary:hover {
    background-color: var(--accent-hover);
    border-color: var(--accent-hover);
    transform: translateY(-1px);
}

.btn-outline-primary {
    border: 1px solid var(--accent-color);
    color: var(--accent-color);
    border-radius: 0.5rem;
    transition: all 0.2s;
}

[data-bs-theme="dark"] .btn-outline-primary {
    color: #f8fafc !important; /* White text for dark mode */
    border-color: rgba(248, 258, 252, 0.2); /* Subtle white border */
}

.btn-outline-primary:hover {
    background-color: var(--accent-color);
    color: white !important;
}

/* Alert Custom (Result Section) */
.alert-custom {
    background-color: var(--bg-body);
    color: var(--text-main);
    border: 1px solid var(--border-color);
    border-radius: 1rem;
}

[data-bs-theme="dark"] .alert-custom {
    background-color: rgba(30, 41, 59, 0.5);
    border-color: var(--border-color);
}

/* Progress */
.progress {
    background-color: var(--border-color);
    border-radius: 9999px;
    height: 0.75rem !important;
}

.progress-bar {
    background-color: var(--accent-color);
}

/* Features */
.feature-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 1rem;
    padding: 1.5rem;
    transition: all 0.2s;
}

.feature-icon {
    color: var(--accent-color);
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

/* Accordion */
.accordion-item {
    border-color: var(--border-color);
    background-color: transparent !important;
}

.accordion-button {
    color: var(--text-main);
    font-weight: 500;
}

.accordion-button:not(.collapsed) {
    color: var(--accent-color);
    background-color: rgba(79, 70, 229, 0.05);
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem;
    border-top: 1px solid var(--border-color);
    background-color: var(--card-bg);
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-top: auto;
}

.footer-link {
    color: var(--text-muted);
    text-decoration: none;
    transition: color 0.2s;
}

.footer-link:hover {
    color: var(--accent-color);
}

@media (max-width: 767.98px) {
    .format-picker {
        grid-template-columns: 1fr;
    }
}