/* === Reset & Base === */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
    --bg: #0f1117;
    --surface: #1a1d27;
    --surface-hover: #242835;
    --border: #2e3345;
    --border-active: #6c72ff;
    --text: #e4e6f0;
    --text-muted: #8b8fa3;
    --accent: #6c72ff;
    --accent-hover: #5a5fe6;
    --accent-glow: rgba(108, 114, 255, 0.25);
    --danger: #ff4d6a;
    --success: #34d399;
    --radius: 10px;
    --radius-lg: 16px;
}

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

/* === Header === */
.app-header {
    text-align: center;
    padding: 2rem 1rem 1rem;
}
.logo {
    font-size: 2rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, var(--accent), #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.tagline {
    color: var(--text-muted);
    font-size: 0.95rem;
    margin-top: 0.25rem;
}

/* === Main === */
.app-main {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 1.5rem 3rem;
}

/* === Steps indicator === */
.steps {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    margin: 1.5rem 0 2rem;
}
.step {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.4rem 0.9rem;
    border-radius: 20px;
    font-size: 0.85rem;
    color: var(--text-muted);
    background: var(--surface);
    border: 1px solid var(--border);
    transition: all 0.3s;
}
.step.active {
    color: #fff;
    background: var(--accent);
    border-color: var(--accent);
}
.step.done {
    color: var(--success);
    border-color: var(--success);
}
.step-num {
    font-weight: 700;
    font-size: 0.8rem;
}

/* === Sections === */
.section {
    display: none;
    animation: fadeIn 0.3s ease;
}
.section.active {
    display: block;
}
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(8px); }
    to   { opacity: 1; transform: translateY(0); }
}

.section h2 {
    font-size: 1.3rem;
    margin-bottom: 1.25rem;
    text-align: center;
}

/* === Buttons === */
.btn {
    display: inline-block;
    padding: 0.65rem 1.5rem;
    border: none;
    border-radius: var(--radius);
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
    text-align: center;
}
.btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}
.btn-primary {
    background: var(--accent);
    color: #fff;
}
.btn-primary:hover:not(:disabled) {
    background: var(--accent-hover);
    box-shadow: 0 0 20px var(--accent-glow);
}
.btn-secondary {
    background: var(--surface);
    color: var(--text);
    border: 1px solid var(--border);
}
.btn-secondary:hover:not(:disabled) {
    background: var(--surface-hover);
}

/* === Upload section === */
.upload-area {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.25rem;
    margin-bottom: 1.25rem;
}

.upload-box {
    position: relative;
    border: 2px dashed var(--border);
    border-radius: var(--radius-lg);
    padding: 2rem 1rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s;
    min-height: 220px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}
.upload-box:hover {
    border-color: var(--accent);
    background: rgba(108, 114, 255, 0.05);
}
.upload-box.dragover {
    border-color: var(--accent);
    background: rgba(108, 114, 255, 0.1);
}
.upload-box.has-image {
    border-style: solid;
    border-color: var(--border-active);
    padding: 0;
}
.upload-box.has-image .upload-placeholder {
    display: none;
}

.upload-placeholder {
    pointer-events: none;
}
.upload-icon {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    opacity: 0.6;
}
.upload-placeholder p {
    font-weight: 600;
    margin-bottom: 0.25rem;
}
.upload-hint {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.upload-preview {
    display: none;
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: calc(var(--radius-lg) - 2px);
}
.upload-box.has-image .upload-preview {
    display: block;
}

.upload-label {
    position: absolute;
    top: 0.5rem;
    left: 0.75rem;
    background: var(--accent);
    color: #fff;
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    padding: 0.15rem 0.5rem;
    border-radius: 4px;
    display: none;
}
.upload-box.has-image .upload-label {
    display: block;
}

.upload-status {
    text-align: center;
    min-height: 1.5rem;
    margin-bottom: 0.75rem;
    font-size: 0.9rem;
}
.upload-status.error { color: var(--danger); }
.upload-status.uploading { color: var(--text-muted); }

#section-upload .btn {
    display: block;
    margin: 0 auto;
}

/* === Effects grid === */
.effects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.effect-card {
    background: var(--surface);
    border: 2px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1.25rem;
    cursor: pointer;
    transition: all 0.2s;
}
.effect-card:hover {
    border-color: var(--accent);
    background: var(--surface-hover);
    transform: translateY(-2px);
}
.effect-card.selected {
    border-color: var(--accent);
    box-shadow: 0 0 20px var(--accent-glow);
}

.effect-card-name {
    font-weight: 700;
    font-size: 1rem;
    margin-bottom: 0.35rem;
}
.effect-card-desc {
    font-size: 0.82rem;
    color: var(--text-muted);
    line-height: 1.4;
}
.effect-card-category {
    display: inline-block;
    margin-top: 0.6rem;
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    padding: 0.15rem 0.5rem;
    border-radius: 4px;
    background: var(--border);
    color: var(--text-muted);
}

#section-effects .btn-secondary {
    display: block;
    margin: 0 auto;
    width: fit-content;
}

/* === Params section === */
.selected-effect-info {
    text-align: center;
    margin-bottom: 1.25rem;
    padding: 0.75rem;
    background: var(--surface);
    border-radius: var(--radius);
    border: 1px solid var(--border);
}
.selected-effect-info strong {
    color: var(--accent);
}

.params-form {
    max-width: 500px;
    margin: 0 auto 1.5rem;
}

.param-group {
    margin-bottom: 1rem;
}
.param-group label {
    display: block;
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 0.35rem;
}
.param-value {
    float: right;
    font-weight: 400;
    color: var(--accent);
    font-size: 0.85rem;
}

.param-group select,
.param-group input[type="range"] {
    width: 100%;
}

.param-group select {
    background: var(--surface);
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 0.5rem 0.75rem;
    font-size: 0.9rem;
}
.param-group select:focus {
    outline: none;
    border-color: var(--accent);
}

input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    height: 6px;
    background: var(--border);
    border-radius: 3px;
    outline: none;
}
input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--accent);
    cursor: pointer;
    border: 2px solid var(--bg);
}
input[type="range"]::-moz-range-thumb {
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--accent);
    cursor: pointer;
    border: 2px solid var(--bg);
}

.param-group input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--accent);
    vertical-align: middle;
    margin-right: 0.5rem;
}
.param-group .checkbox-label {
    display: flex;
    align-items: center;
    cursor: pointer;
}

.param-description {
    font-size: 0.78rem;
    color: var(--text-muted);
    margin-top: 0.2rem;
}

.params-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

/* === Progress === */
.progress-container {
    text-align: center;
}
.progress-bar-wrap {
    width: 100%;
    max-width: 500px;
    height: 10px;
    background: var(--border);
    border-radius: 5px;
    margin: 1.25rem auto;
    overflow: hidden;
}
.progress-bar {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, var(--accent), #a78bfa);
    border-radius: 5px;
    transition: width 0.3s ease;
}
.progress-text {
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* === Result === */
.result-container {
    text-align: center;
}
.result-container video {
    width: 100%;
    max-width: 720px;
    border-radius: var(--radius-lg);
    margin: 1rem auto;
    display: block;
    background: #000;
}
.result-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-top: 1rem;
}

/* === Error === */
.error-container {
    text-align: center;
}
.error-message {
    color: var(--danger);
    margin: 1rem 0;
    padding: 1rem;
    background: rgba(255, 77, 106, 0.1);
    border-radius: var(--radius);
    border: 1px solid rgba(255, 77, 106, 0.2);
}
.error-container .btn {
    margin-top: 0.5rem;
}

/* === Responsive === */
@media (max-width: 600px) {
    .upload-area {
        grid-template-columns: 1fr;
    }
    .effects-grid {
        grid-template-columns: 1fr 1fr;
    }
    .steps {
        flex-wrap: wrap;
    }
    .logo { font-size: 1.6rem; }
}