/* --- Global Styles & Fintech Pro Theme --- */
:root {
    --bg-primary: #020412;
    --bg-card: #111827;
    --accent-primary: #00d1ff;
    --accent-secondary: #ad53ff;
    --text-primary: #e5e7eb;
    --text-secondary: #9ca3af;
    --border-color: #374151;
    --glow-shadow-primary: 0 0 20px rgba(0, 209, 255, 0.4);
    --glow-shadow-secondary: 0 0 20px rgba(173, 83, 255, 0.4);
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-primary);
    background-image:
        radial-gradient(circle at 15% 50%, rgba(0, 209, 255, 0.1), transparent 25%),
        radial-gradient(circle at 85% 30%, rgba(173, 83, 255, 0.1), transparent 25%);
    background-attachment: fixed;
    color: var(--text-primary);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
    min-height: 100vh;
    margin: 0;
    padding: 3rem 2rem;
    box-sizing: border-box;
}

/* --- Header --- */
.main-header, .page-header {
    text-align: center;
    margin-bottom: 4rem;
}

.main-header h1, .page-header h1 {
    font-size: 3.2rem;
    font-weight: 800;
    background: linear-gradient(90deg, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.5rem;
    text-shadow: var(--glow-shadow-primary), var(--glow-shadow-secondary);
}

.main-header p, .page-header p {
    font-size: 1.2rem;
    color: var(--text-secondary);
    max-width: 600px;
}

/* --- Button Grid --- */
.topic-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    width: 100%;
    max-width: 1100px;
}

/* --- Base Style for Interactive Cards (Buttons, Accordions) --- */
.topic-button, .accordion {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 10px rgba(0,0,0,0.3);
    transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
    border-radius: 12px;
}

.topic-button:hover, .accordion:hover {
    transform: translateY(-5px);
    border-color: var(--accent-primary);
    box-shadow: 0 10px 25px rgba(0,0,0,0.4), var(--glow-shadow-primary);
}

/* --- Individual Buttons --- */
.topic-button {
    color: var(--text-primary);
    text-decoration: none;
    padding: 1.5rem 2rem;
    text-align: center;
    font-size: 1.2rem;
    font-weight: 600;
}

/* --- Back Link for Sub-Pages --- */
.back-link {
    display: inline-block;
    color: var(--accent-primary);
    text-decoration: none;
    font-weight: 600;
    margin-bottom: 1.5rem;
    transition: color 0.2s ease, text-shadow 0.2s ease;
}

.back-link:hover {
    color: var(--accent-secondary);
    text-shadow: var(--glow-shadow-secondary);
}

/* --- Content & Accordion Styles --- */
.content-container {
    width: 100%;
    max-width: 1000px;
}

.accordion {
    position: relative;
    color: var(--text-primary);
    cursor: pointer;
    padding: 20px 60px 20px 30px;
    width: 100%;
    text-align: left;
    outline: none;
    font-size: 1.15rem;
    font-weight: 600;
    margin-top: 1rem;
}

.accordion::after {
    content: '>';
    font-family: monospace;
    font-size: 1.8rem;
    color: var(--text-secondary);
    position: absolute;
    right: 30px;
    top: 50%;
    transform: translateY(-50%) rotate(90deg);
    transition: transform 0.4s cubic-bezier(0.19, 1, 0.22, 1), color 0.3s ease;
}

.accordion.active::after {
    transform: translateY(-50%) rotate(-90deg);
    color: var(--accent-primary);
}

.accordion.active {
    border-bottom-left-radius: 0;
    border-bottom-right-radius: 0;
    border-color: var(--accent-primary);
    box-shadow: 0 10px 25px rgba(0,0,0,0.4), var(--glow-shadow-primary);
    border-bottom: 1px solid var(--border-color);
}

.panel {
    padding: 0 30px;
    background-color: var(--bg-card);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.5s ease-in-out, padding 0.5s ease-in-out;
    border: 1px solid var(--border-color);
    border-top: none;
    border-bottom-left-radius: 12px;
    border-bottom-right-radius: 12px;
    box-shadow: inset 0 6px 10px -5px rgba(0,0,0,0.5);
}

/* --- Content Formatting Inside Panels --- */
.panel h4 {
    color: var(--accent-primary);
    margin-top: 2rem;
    margin-bottom: 0.5rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

.content-container h4 {
    color: var(--accent-primary);
    font-size: 1.5rem;
    margin-top: 3rem;
    text-align: center;
}

.panel p, .panel li {
    line-height: 1.7;
    color: var(--text-primary);
}

.panel ul, .panel ol {
    padding-left: 20px;
    margin-bottom: 1.5rem;
}

.panel blockquote {
    border-left: 4px solid var(--accent-primary);
    padding: 10px 20px;
    margin: 1.5rem 0;
    font-style: italic;
    color: var(--text-secondary);
    background-color: rgba(0, 209, 255, 0.05);
    border-radius: 4px;
}

/* --- Table Styles --- */
.table-container {
    margin-top: 1rem;
    overflow-x: auto;
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: 0 4px 10px rgba(0,0,0,0.3);
}

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

table th, table td {
    padding: 12px 15px;
    border-bottom: 1px solid var(--border-color);
}

table th {
    color: var(--accent-primary);
    font-weight: 600;
    font-size: 1.1rem;
}

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

table tbody tr {
    transition: background-color 0.2s ease;
}

table tbody tr:hover {
    background-color: rgba(0, 209, 255, 0.05);
}


/* --- Mobile Responsiveness --- */
@media (max-width: 600px) {
    body {
        padding: 3rem 1rem;
    }

    .main-header, .page-header {
        margin-bottom: 3rem;
    }

    .main-header h1, .page-header h1 {
        font-size: 2.5rem;
    }

    .main-header p, .page-header p {
        font-size: 1.1rem;
    }

    .accordion {
        padding: 18px 50px 18px 20px;
    }

    .accordion::after {
        right: 20px;
    }
}

@media (max-width: 480px) {
    .topic-grid {
        grid-template-columns: repeat(2, 1fr); /* two buttons per row */
        gap: 1rem;
    }

    .main-header h1, .page-header h1 {
        font-size: 1.8rem;
    }

    .main-header p, .page-header p {
        font-size: 0.95rem;
    }

    .topic-button {
        font-size: 1rem;
        padding: 1.3rem; /* bigger touch padding */
        min-height: 56px;
    }

    .accordion {
        padding: 22px 50px 22px 20px;
        font-size: 1rem;
        min-height: 56px;
    }

    .accordion::after {
        right: 16px;
        font-size: 1.8rem; /* larger touch target for expand icon */
    }

    .back-link {
        font-size: 1rem;
        padding: 0.8rem 0; /* bigger clickable area */
    }
}