/* ========== CSS Variables ========== */
:root {
    --bg-primary: #0a0a0f;
    --bg-secondary: #12121a;
    --bg-tertiary: #1a1a25;
    --bg-card: rgba(30, 30, 45, 0.6);
    --bg-glass: rgba(255, 255, 255, 0.03);

    --text-primary: #ffffff;
    --text-secondary: #a0a0b0;
    --text-muted: #606070;

    --accent-primary: #6366f1;
    --accent-secondary: #8b5cf6;
    --accent-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #a855f7 100%);
    --accent-glow: rgba(99, 102, 241, 0.4);

    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;

    --border-color: rgba(255, 255, 255, 0.08);
    --border-hover: rgba(255, 255, 255, 0.15);

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;

    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 30px var(--accent-glow);

    --transition-fast: 0.15s ease;
    --transition-normal: 0.25s ease;
    --transition-slow: 0.4s ease;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

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

/* Background gradient effect */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        radial-gradient(ellipse 80% 50% at 50% -20%, rgba(99, 102, 241, 0.15) 0%, transparent 50%),
        radial-gradient(ellipse 60% 40% at 80% 60%, rgba(139, 92, 246, 0.1) 0%, transparent 50%),
        radial-gradient(ellipse 50% 30% at 20% 80%, rgba(168, 85, 247, 0.08) 0%, transparent 50%);
    pointer-events: none;
    z-index: -1;
}

/* ========== Layout ========== */
.app-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ========== Header ========== */
.header {
    text-align: center;
    padding: 2rem 0 3rem;
    animation: fadeInDown 0.6s ease;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    margin-bottom: 0.5rem;
}

.logo-icon {
    font-size: 2.5rem;
    animation: float 3s ease-in-out infinite;
}

.logo h1 {
    font-size: 2rem;
    font-weight: 700;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1rem;
    font-weight: 400;
}

/* ========== Steps Indicator ========== */
.steps-indicator {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0;
    margin-bottom: 2.5rem;
    padding: 1.25rem 2rem;
    background: var(--bg-glass);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    backdrop-filter: blur(10px);
}

.step {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-muted);
    transition: var(--transition-normal);
}

.step.active {
    color: var(--text-primary);
}

.step.active .step-number {
    background: var(--accent-gradient);
    color: white;
    box-shadow: var(--shadow-glow);
}

.step.completed .step-number {
    background: var(--success);
    color: white;
}

.step-number {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.875rem;
    font-weight: 600;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    transition: var(--transition-normal);
}

.step span {
    font-size: 0.875rem;
    font-weight: 500;
}

.step-line {
    width: 60px;
    height: 2px;
    background: var(--border-color);
    margin: 0 1rem;
}

/* ========== Upload Section - Multi File ========== */
.upload-section {
    margin-bottom: 2rem;
    animation: fadeInUp 0.5s ease;
}

.upload-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}

.upload-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.25rem;
    transition: var(--transition-normal);
}

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

.upload-card.has-file {
    border-color: var(--success);
}

.upload-card-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.upload-card-icon {
    font-size: 1.25rem;
}

.upload-card-title {
    font-weight: 600;
    font-size: 1rem;
}

.upload-card-badge {
    margin-left: auto;
    padding: 0.25rem 0.5rem;
    border-radius: var(--radius-sm);
    font-size: 0.7rem;
    font-weight: 500;
}

.upload-card-badge.required {
    background: rgba(239, 68, 68, 0.15);
    color: var(--error);
}

.upload-card-badge.optional {
    background: rgba(16, 185, 129, 0.15);
    color: var(--success);
}

.upload-zone {
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-md);
    padding: 2rem 1rem;
    text-align: center;
    background: var(--bg-glass);
    cursor: pointer;
    transition: var(--transition-normal);
}

.upload-zone:hover {
    border-color: var(--accent-primary);
    background: rgba(99, 102, 241, 0.05);
}

.upload-zone.drag-over {
    border-color: var(--accent-primary);
    background: rgba(99, 102, 241, 0.1);
    transform: scale(1.02);
}

.upload-icon {
    width: 48px;
    height: 48px;
    margin: 0 auto 1rem;
    color: var(--accent-primary);
    opacity: 0.8;
}

.upload-icon svg {
    width: 100%;
    height: 100%;
}

.upload-zone p {
    color: var(--text-secondary);
    font-size: 0.85rem;
    margin-bottom: 0.25rem;
}

.file-hint {
    font-size: 0.75rem !important;
    color: var(--text-muted) !important;
}

.file-info {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.875rem 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    margin-top: 0.75rem;
    animation: fadeIn 0.3s ease;
}

.file-icon {
    font-size: 1.5rem;
}

.file-details {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 0.125rem;
    min-width: 0;
}

.file-name {
    font-weight: 500;
    font-size: 0.875rem;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.file-meta {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.sheet-selector {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-top: 0.375rem;
}

.sheet-selector label {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.sheet-selector select {
    padding: 0.25rem 0.5rem;
    font-size: 0.75rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    cursor: pointer;
    min-width: 120px;
}

.sheet-selector select:hover {
    border-color: var(--accent-primary);
}

.sheet-selector select:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.2);
}

.btn-remove {
    width: 28px;
    height: 28px;
    border: none;
    background: rgba(239, 68, 68, 0.1);
    color: var(--error);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 1.1rem;
    transition: var(--transition-fast);
    flex-shrink: 0;
}

.btn-remove:hover {
    background: rgba(239, 68, 68, 0.2);
}

/* ========== Formula Section ========== */
.formula-section {
    margin-bottom: 2rem;
    animation: fadeInUp 0.5s ease;
}

.section-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.formula-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.formula-card {
    padding: 1.25rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    text-align: center;
    cursor: pointer;
    transition: var(--transition-normal);
    position: relative;
}

.formula-card:hover {
    border-color: var(--accent-primary);
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.formula-card.selected {
    border-color: var(--accent-primary);
    background: rgba(99, 102, 241, 0.1);
    box-shadow: var(--shadow-glow);
}

.formula-icon {
    font-size: 1.75rem;
    margin-bottom: 0.5rem;
}

.formula-name {
    font-weight: 600;
    font-size: 0.95rem;
    margin-bottom: 0.25rem;
}

.formula-desc {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.formula-tag {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    padding: 0.2rem 0.4rem;
    background: rgba(16, 185, 129, 0.2);
    color: var(--success);
    border-radius: var(--radius-sm);
    font-size: 0.6rem;
    font-weight: 500;
}

/* ========== Params Container ========== */
.params-container {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    animation: fadeIn 0.3s ease;
}

.params-title {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

.cross-table-notice {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1rem;
    background: rgba(16, 185, 129, 0.1);
    border: 1px solid rgba(16, 185, 129, 0.3);
    border-radius: var(--radius-md);
    margin-bottom: 1rem;
    font-size: 0.85rem;
    color: var(--success);
}

.notice-icon {
    font-size: 1rem;
}

.params-form {
    display: grid;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-group label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.form-group .label-hint {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 400;
}

.form-group select,
.form-group input {
    padding: 0.75rem 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 0.9rem;
    font-family: inherit;
    transition: var(--transition-fast);
}

.form-group select:focus,
.form-group input:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.form-group select option {
    background: var(--bg-secondary);
    color: var(--text-primary);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

/* ========== Buttons ========== */
.btn-primary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.875rem 2rem;
    background: var(--accent-gradient);
    border: none;
    border-radius: var(--radius-md);
    color: white;
    font-size: 1rem;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition-normal);
    box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-glow);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-secondary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 0.9rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition-normal);
}

.btn-secondary:hover {
    border-color: var(--accent-primary);
    background: rgba(99, 102, 241, 0.1);
}

.btn-icon {
    font-size: 1.1rem;
}

/* ========== Preview Section ========== */
.preview-section {
    flex: 1;
    display: flex;
    flex-direction: column;
    animation: fadeInUp 0.5s ease;
}

.preview-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 1rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.preview-tabs {
    display: flex;
    gap: 0.5rem;
}

.preview-tab {
    padding: 0.5rem 1rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    font-size: 0.85rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition-fast);
}

.preview-tab:hover {
    border-color: var(--accent-primary);
}

.preview-tab.active {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
    color: white;
}

.preview-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.row-count {
    font-size: 0.875rem;
    color: var(--text-muted);
}

.table-wrapper {
    flex: 1;
    overflow: auto;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    max-height: 400px;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.875rem;
}

.data-table th,
.data-table td {
    padding: 0.75rem 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
    white-space: nowrap;
}

.data-table th {
    background: var(--bg-tertiary);
    font-weight: 600;
    color: var(--text-secondary);
    position: sticky;
    top: 0;
    z-index: 10;
}

.data-table tr:hover td {
    background: rgba(99, 102, 241, 0.05);
}

.data-table td.result-col {
    color: var(--success);
    font-weight: 500;
    background: rgba(16, 185, 129, 0.05);
}

.cell-na {
    color: var(--error) !important;
}

/* ========== Footer ========== */
.footer {
    text-align: center;
    padding: 2rem 0 1rem;
    color: var(--text-muted);
    font-size: 0.8rem;
}

/* ========== Loading Overlay ========== */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(10, 10, 15, 0.9);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 1.5rem;
    z-index: 1000;
    backdrop-filter: blur(4px);
}

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

.loading-text {
    color: var(--text-secondary);
    font-size: 1rem;
}

/* ========== Toast ========== */
.toast-container {
    position: fixed;
    top: 2rem;
    right: 2rem;
    z-index: 2000;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.toast {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 1.25rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    animation: slideInRight 0.3s ease;
    max-width: 400px;
}

.toast.success {
    border-left: 3px solid var(--success);
}

.toast.error {
    border-left: 3px solid var(--error);
}

.toast.warning {
    border-left: 3px solid var(--warning);
}

.toast-icon {
    font-size: 1.25rem;
}

.toast-message {
    flex: 1;
    font-size: 0.9rem;
}

/* ========== Animations ========== */
@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(100px);
    }

    to {
        opacity: 1;
        transform: translateX(0);
    }
}

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

@keyframes float {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-8px);
    }
}

/* ========== Pipeline Container ========== */
.pipeline-container {
    margin-top: 2rem;
    padding: 1.5rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    animation: fadeIn 0.3s ease;
}

.pipeline-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 1.25rem;
}

.pipeline-header h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.pipeline-hint {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.pipeline-steps {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    margin-bottom: 1.25rem;
}

.pipeline-step {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    position: relative;
}

.pipeline-step::before {
    content: '';
    position: absolute;
    left: 1.5rem;
    top: -0.75rem;
    width: 2px;
    height: 0.75rem;
    background: var(--accent-primary);
}

.pipeline-step:first-child::before {
    display: none;
}

.pipeline-step-number {
    width: 28px;
    height: 28px;
    background: var(--accent-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.85rem;
    font-weight: 600;
    color: white;
    flex-shrink: 0;
}

.pipeline-step-info {
    flex: 1;
    min-width: 0;
}

.pipeline-step-formula {
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.pipeline-step-desc {
    font-size: 0.8rem;
    color: var(--text-muted);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.pipeline-step-result {
    font-size: 0.75rem;
    color: var(--success);
    background: rgba(16, 185, 129, 0.1);
    padding: 0.25rem 0.5rem;
    border-radius: var(--radius-sm);
}

.pipeline-step-remove {
    width: 24px;
    height: 24px;
    border: none;
    background: rgba(239, 68, 68, 0.1);
    color: var(--error);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.9rem;
    transition: var(--transition-fast);
    flex-shrink: 0;
}

.pipeline-step-remove:hover {
    background: rgba(239, 68, 68, 0.2);
}

.pipeline-actions {
    display: flex;
    gap: 1rem;
}

.btn-outline {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition-normal);
}

.btn-outline:hover {
    border-color: var(--error);
    color: var(--error);
}

/* ========== Responsive ========== */
@media (max-width: 768px) {
    .app-container {
        padding: 1rem;
    }

    .logo h1 {
        font-size: 1.5rem;
    }

    .steps-indicator {
        padding: 1rem;
    }

    .step span {
        display: none;
    }

    .step-line {
        width: 30px;
    }

    .upload-grid {
        grid-template-columns: 1fr;
    }

    .formula-cards {
        grid-template-columns: repeat(2, 1fr);
    }

    .form-row {
        grid-template-columns: 1fr;
    }

    .preview-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .preview-tabs {
        width: 100%;
        overflow-x: auto;
    }

    .toast-container {
        left: 1rem;
        right: 1rem;
    }

    .toast {
        max-width: none;
    }
}