:root {
    /* Corporate Color Palette */
    --primary-color: #1e293b; /* Deep Navy */
    --accent-color: #2563eb;  /* Modern Blue */
    --accent-hover: #1d4ed8;
    --bg-color: #f1f5f9;      /* Light Gray-Blue */
    --surface-color: #ffffff;
    --text-main: #0f172a;
    --text-muted: #475569;
    --border-color: #e2e8f0;
    --success-color: #10b981;
    --danger-color: #ef4444;
    
    /* Shadows & Effects */
    --shadow-soft: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
    --shadow-premium: 0 10px 15px -3px rgba(0, 0, 0, 0.07), 0 4px 6px -4px rgba(0, 0, 0, 0.05);
    --transition-base: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    font-family: 'Inter', 'Pretendard', -apple-system, BlinkMacSystemFont, sans-serif;
    min-height: 100vh;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

/* Header Redesign: Deep & Professional */
.app-header {
    background-color: var(--primary-color);
    color: white;
    padding: 0.75rem 2rem;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header-container h1 {
    font-size: 1.1rem;
    font-weight: 800;
    letter-spacing: -0.01em;
    text-transform: uppercase;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.header-container h1 .accent {
    color: #38bdf8;
    background: rgba(56, 189, 248, 0.15);
    padding: 0.1rem 0.4rem;
    border-radius: 4px;
    font-size: 0.75rem;
}

.main-nav {
    display: flex;
    gap: 0.25rem;
}

.nav-link {
    background: none;
    border: none;
    color: rgba(255, 255, 255, 0.7);
    font-size: 0.85rem;
    font-weight: 600;
    padding: 0.5rem 1rem;
    cursor: pointer;
    transition: var(--transition-base);
    border-radius: 4px;
}

.nav-link:hover {
    color: white;
    background-color: rgba(255, 255, 255, 0.1);
}

.nav-link.active {
    color: white;
    background-color: var(--accent-color);
}

.dashboard {
    max-width: 1200px;
    margin: 2.5rem auto;
    padding: 0 2rem;
}

.content-section {
    animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 1rem;
}

.section-header h2 {
    font-size: 1.75rem;
    font-weight: 800;
    color: var(--primary-color);
    letter-spacing: -0.03em;
}

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

.search-box input {
    width: 320px;
    padding: 0.75rem 1.25rem;
    border-radius: 10px;
    border: 1px solid var(--border-color);
    background-color: var(--surface-color);
    color: var(--text-main);
    font-size: 0.9rem;
    outline: none;
    transition: var(--transition-base);
    box-shadow: var(--shadow-soft);
}

.search-box input:focus {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.1);
}

.primary-btn {
    background-color: var(--accent-color);
    color: white;
    border: none;
    padding: 0.75rem 1.75rem;
    border-radius: 10px;
    font-weight: 700;
    font-size: 0.9rem;
    cursor: pointer;
    transition: var(--transition-base);
    box-shadow: 0 4px 10px rgba(37, 99, 235, 0.2);
}

.primary-btn:hover {
    background-color: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 6px 15px rgba(37, 99, 235, 0.3);
}

.secondary-btn {
    background-color: white;
    color: var(--text-main);
    border: 1px solid var(--border-color);
    padding: 0.75rem 1.75rem;
    border-radius: 10px;
    font-weight: 700;
    font-size: 0.9rem;
    cursor: pointer;
    transition: var(--transition-base);
    box-shadow: var(--shadow-soft);
}

.secondary-btn:hover {
    background-color: #f8fafc;
    border-color: #cbd5e1;
}

.table-wrapper {
    background-color: var(--surface-color);
    border-radius: 16px;
    border: 1px solid var(--border-color);
    overflow: hidden;
    box-shadow: var(--shadow-premium);
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    text-align: left;
}

.data-table th {
    background-color: #f8fafc;
    padding: 1.25rem 1.5rem;
    font-size: 0.75rem;
    font-weight: 800;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.075em;
    border-bottom: 1px solid var(--border-color);
}

.data-table td {
    padding: 1.5rem;
    border-bottom: 1px solid #f1f5f9;
    font-size: 0.95rem;
    color: var(--text-main);
    transition: var(--transition-base);
}

.data-table tr:last-child td {
    border-bottom: none;
}

.data-table tr:hover td {
    background-color: #f9fafb;
}

.data-table td strong {
    color: var(--primary-color);
    font-weight: 700;
}

.action-btns {
    display: flex;
    gap: 0.75rem;
}

.edit-btn, .delete-btn {
    padding: 0.5rem 1rem;
    border-radius: 8px;
    font-size: 0.8rem;
    font-weight: 700;
    cursor: pointer;
    border: 1px solid transparent;
    transition: var(--transition-base);
}

.edit-btn {
    background-color: #eff6ff;
    color: var(--accent-color);
}

.edit-btn:hover {
    background-color: var(--accent-color);
    color: white;
}

.delete-btn {
    background-color: #fff1f2;
    color: var(--danger-color);
}

.delete-btn:hover {
    background-color: var(--danger-color);
    color: white;
}

.empty-state {
    padding: 6rem 2rem;
    text-align: center;
    color: var(--text-muted);
}

.hidden {
    display: none !important;
}

.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(15, 23, 42, 0.6);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    backdrop-filter: blur(12px);
}

.modal-content {
    background-color: var(--surface-color);
    width: 95%;
    max-width: 520px;
    border-radius: 24px;
    padding: 3rem;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2.5rem;
}

.modal-header h2 {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary-color);
}

.close-btn {
    background: #f1f5f9;
    border: none;
    color: var(--text-muted);
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
}

.form-group {
    margin-bottom: 1.75rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.6rem;
    font-size: 0.85rem;
    font-weight: 700;
}

.form-group input, .form-group textarea {
    width: 100%;
    padding: 0.85rem 1.15rem;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    background-color: #f8fafc;
    color: var(--text-main);
    outline: none;
}

.form-actions {
    display: flex;
    justify-content: flex-end;
    gap: 1rem;
    margin-top: 3rem;
}

@media (max-width: 768px) {
    .app-header {
        padding: 1rem;
    }
    .header-container {
        flex-direction: column;
        gap: 1.25rem;
    }
    .dashboard {
        margin: 1.5rem auto;
        padding: 0 1rem;
    }
    .section-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1.5rem;
    }
    .controls {
        width: 100%;
        flex-direction: column;
    }
    .search-box, .search-box input {
        width: 100%;
    }
    .primary-btn {
        width: 100%;
    }
    .table-wrapper {
        border: none;
        background: none;
        box-shadow: none;
    }
    .data-table tr {
        margin-bottom: 1.5rem;
        border: 1px solid var(--border-color);
        border-radius: 20px;
        background-color: var(--surface-color);
        padding: 1.5rem;
        box-shadow: var(--shadow-premium);
        display: block;
    }
    .data-table td {
        border: none;
        padding: 0.75rem 0;
        display: flex;
        justify-content: space-between;
        align-items: center;
    }
    .data-table td::before {
        content: attr(data-label);
        font-weight: 800;
        color: var(--text-muted);
        font-size: 0.7rem;
        text-transform: uppercase;
    }

    /* Marketing Analyzer Native Styles */
    .marketing-layout {
        display: grid;
        grid-template-columns: 340px 1fr;
        gap: 2rem;
        align-items: start;
    }

    .marketing-sidebar {
        background-color: var(--surface-color);
        border-radius: 20px;
        padding: 2rem;
        border: 1px solid var(--border-color);
        box-shadow: var(--shadow-premium);
    }

    .marketing-sidebar .card-title {
        font-size: 1.25rem;
        font-weight: 800;
        margin-bottom: 1.5rem;
        color: var(--primary-color);
    }

    .marketing-sidebar textarea {
        width: 100%;
        min-height: 200px;
        padding: 1rem;
        border-radius: 12px;
        border: 1px solid var(--border-color);
        background-color: #f8fafc;
        color: var(--text-main);
        font-family: inherit;
        font-size: 0.95rem;
        line-height: 1.6;
        resize: vertical;
        outline: none;
        transition: var(--transition-base);
    }

    .marketing-sidebar textarea:focus {
        border-color: var(--accent-color);
        box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.1);
    }

    .marketing-sidebar .notice {
        margin-top: 1rem;
        font-size: 0.8rem;
        color: var(--text-muted);
        line-height: 1.5;
    }

    .marketing-sidebar .speed-note {
        color: var(--accent-color);
        font-weight: 600;
    }

    .metrics-grid {
        display: grid;
        grid-template-columns: repeat(3, 1fr);
        gap: 1.25rem;
        margin-bottom: 2rem;
    }

    .metric-card {
        background-color: var(--surface-color);
        border: 1px solid var(--border-color);
        border-radius: 16px;
        padding: 1.5rem;
        box-shadow: var(--shadow-soft);
    }

    .metric-card span {
        display: block;
        font-size: 0.75rem;
        font-weight: 800;
        color: var(--text-muted);
        text-transform: uppercase;
        margin-bottom: 0.5rem;
    }

    .metric-card strong {
        font-size: 1.75rem;
        font-weight: 800;
        color: var(--primary-color);
    }

    .analysis-card {
        background-color: var(--surface-color);
        border: 1px solid var(--border-color);
        border-radius: 20px;
        padding: 2rem;
        margin-bottom: 2rem;
        box-shadow: var(--shadow-premium);
        animation: fadeIn 0.5s ease;
    }

    .analysis-header {
        display: flex;
        justify-content: space-between;
        align-items: center;
        margin-bottom: 1.5rem;
    }

    .analysis-header .main-kw {
        font-size: 1.5rem;
        font-weight: 900;
        color: var(--primary-color);
    }

    .recommendation-pill {
        background-color: #ecfeff;
        color: #0e7490;
        padding: 0.5rem 1rem;
        border-radius: 999px;
        font-size: 0.8rem;
        font-weight: 800;
    }

    .summary-box {
        background-color: #f8fbff;
        border: 1px solid #e0e7ff;
        border-radius: 16px;
        padding: 1.5rem;
        margin-bottom: 2rem;
        line-height: 1.7;
        font-size: 0.95rem;
    }

    .channel-grid {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
        gap: 1.5rem;
        margin-top: 2rem;
    }

    .channel-item {
        border: 1px solid var(--border-color);
        border-radius: 16px;
        padding: 1.5rem;
        background-color: #ffffff;
    }

    .channel-name {
        font-weight: 800;
        font-size: 1rem;
        margin-bottom: 1rem;
        display: flex;
        justify-content: space-between;
    }

    .score-bar {
        height: 8px;
        background-color: #f1f5f9;
        border-radius: 999px;
        overflow: hidden;
        margin-bottom: 1rem;
    }

    .score-fill {
        height: 100%;
        background: linear-gradient(90deg, #38bdf8, #10b981);
        border-radius: 999px;
    }

    @media (max-width: 1024px) {
        .marketing-layout {
            grid-template-columns: 1fr;
        }
    }

}