/* ===== BASE ===== */
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.8;
    color: #34495e;
    max-width: 900px;
    margin: 20px auto;
    padding: 25px;
    background-color: #ecf0f1;
    border-radius: 8px;
}

/* ===== HEADINGS ===== */
h1, h2, h3 {
    color: #2c3e50;
    border-bottom: 2px solid #3498db;
    padding-bottom: 10px;
}
h1 { margin-top: 0; font-size: 1.8em; }
h2 { margin-top: 40px; }
h3 { margin-top: 30px; border-bottom-width: 1px; }

/* ===== CODE ===== */
code {
    background-color: #dfe6e9;
    padding: 2px 6px;
    border-radius: 4px;
    font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, Courier, monospace;
    font-size: 0.9em;
}
pre code {
    background-color: transparent;
    padding: 0;
    font-size: 1em;
}
pre {
    background-color: #212529;
    color: #e9ecef;
    padding: 20px;
    border-radius: 8px;
    overflow-x: auto;
    border: 1px solid #495057;
    font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, Courier, monospace;
}

/* ===== INFO BOXES ===== */
.info-box,
.highlight-box,
.analogy-box,
.architecture-box,
.troubleshooting-box,
.interview-box {
    background-color: #ffffff;
    border-left: 5px solid #3498db;
    padding: 20px;
    margin: 20px 0;
    border-radius: 0 8px 8px 0;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}
.analogy-box { border-left-color: #f1c40f; }
.architecture-box { border-left-color: #e74c3c; }
.troubleshooting-box { border-left-color: #e74c3c; }
.interview-box {
    background-color: #fdf9e7;
    border-left: 5px solid #f1c40f;
}
.interview-box h4 {
    color: #d35400;
    margin-top: 0;
    display: flex;
    align-items: center;
    border: none;
}
.interview-box h4::before {
    content: '💡';
    margin-right: 10px;
    font-size: 1.5em;
}
.troubleshooting-box h4 { color: #c0392b; margin-top: 0; }

/* ===== TABLE ===== */
table { width: 100%; border-collapse: collapse; margin: 25px 0; }
th, td { border: 1px solid #dee2e6; padding: 12px; text-align: left; }
th { background-color: #f2f2f2; font-weight: bold; }

/* ===== TEXT HELPERS ===== */
strong { color: #c0392b; font-weight: bold; }
.text-bold { font-weight: bold; }
.highlight { color: #e67e22; font-weight: bold; }
.problem { color: #e74c3c; font-weight: bold; }
.solution { color: #2ecc71; font-weight: bold; }

/* ===== LISTS ===== */
ul { padding-left: 20px; }
li { margin-bottom: 10px; }

/* ===== BLOCKQUOTE ===== */
blockquote {
    border-left: 4px solid #3498db;
    padding: 10px 20px;
    margin: 20px 0;
    color: #555;
    background-color: #f8f9fa;
}

/* ===== CONTAINER (LeetCode pages wrapper — neutralized) ===== */
.container {
    background-color: transparent;
    padding: 0;
    box-shadow: none;
    border-radius: 0;
}

/* ===== NAVIGATION — system style (.navigation / .nav-link) ===== */
.navigation {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 40px;
    padding-top: 20px;
    border-top: 2px solid #bdc3c7;
}
.nav-link {
    text-decoration: none;
    background-color: #34495e;
    color: #ffffff;
    padding: 10px 20px;
    border-radius: 5px;
    font-weight: bold;
    transition: background-color 0.3s;
}
.nav-link:hover { background-color: #3498db; }
.nav-link.home { background-color: #95a5a6; }
.nav-link.home:hover { background-color: #7f8c8d; }
.top-nav {
    margin-bottom: 40px;
    padding-bottom: 20px;
    border-bottom: 2px solid #bdc3c7;
    border-top: none;
    margin-top: 0;
}

/* ===== NAVIGATION — LeetCode style (.page-nav / .nav-btn) ===== */
.page-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.page-nav.top-nav {
    margin-bottom: 30px;
    border-bottom: 2px solid #bdc3c7;
    padding-bottom: 20px;
    border-top: none;
    margin-top: 0;
}
.page-nav.bottom-nav {
    margin-top: 50px;
    padding-top: 20px;
    border-top: 2px solid #bdc3c7;
}
.nav-btn {
    padding: 10px 20px;
    border: none;
    border-radius: 5px;
    text-decoration: none;
    color: #ffffff;
    font-weight: bold;
    background-color: #34495e;
    transition: background-color 0.3s;
}
.nav-btn:not(.disabled):hover { background-color: #3498db; }
.nav-btn.list { background-color: #95a5a6; }
.nav-btn.list:hover { background-color: #7f8c8d; }
.nav-btn.disabled {
    color: #bdc3c7;
    background-color: #d5d8dc;
    pointer-events: none;
}

/* ===== DIAGRAM (Kafka) ===== */
.diagram-container {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
    margin: 20px 0;
    background-color: #f8f9fa;
    border-radius: 8px;
}
.node {
    background-color: #fff;
    border: 2px solid #bdc3c7;
    border-radius: 5px;
    padding: 10px 15px;
    margin: 0 10px;
    text-align: center;
    box-shadow: 0 2px 4px rgba(0,0,0,0.08);
}
.kafka-node {
    background-color: #3498db;
    color: white;
    border-color: #2980b9;
    padding: 20px;
    font-weight: bold;
}
.arrow {
    font-size: 24px;
    color: #7f8c8d;
}

/* ===== LEET CODE — problem description box ===== */
.problem-description {
    margin-bottom: 40px;
    padding: 20px;
    background-color: #f8f9fa;
    border-radius: 8px;
    border: 1px solid #e9ecef;
}
.problem-description h2 { border-bottom: none; }
.problem-description pre { margin-top: 10px; margin-bottom: 10px; }

/* ===== DEEP DIVE BOX ===== */
.deep-dive-box {
    background-color: #f4f6f7;
    border-left: 5px solid #7f8c8d;
    padding: 20px;
    margin: 30px 0;
    border-radius: 0 8px 8px 0;
}

/* ===== SUMMARY / INTERVIEW-TIP BOX ===== */
.summary-box, .interview-tip {
    background-color: #ffffff;
    border-left: 5px solid #2ecc71;
    padding: 20px;
    margin: 20px 0;
    border-radius: 0 8px 8px 0;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}
.summary-box h4 { color: #27ae60; margin-top: 0; }

/* ===== FLOW DIAGRAM (Cassandra write/read path) ===== */
.flow-diagram {
    background-color: #fff;
    padding: 20px;
    border-radius: 8px;
    margin: 20px 0;
    text-align: center;
    border: 1px solid #d1d8dd;
}
.flow-diagram h4 { margin-top: 0; }
.flow-box {
    display: inline-block;
    background-color: #ecf0f1;
    padding: 10px 15px;
    border-radius: 5px;
    margin: 5px;
    border: 1px solid #bdc3c7;
    font-weight: bold;
}
.flow-box.memory { background-color: #e8f6f3; border-color: #1abc9c; }
.flow-box.disk   { background-color: #fdedec; border-color: #e74c3c; }

/* ===== MERMAID DIAGRAM ===== */
.mermaid { text-align: center; margin: 30px 0; }

/* ===== KAFKA — Broker / Cluster / Offset diagrams ===== */
.broker {
    border: 2px dashed #7f8c8d;
    border-radius: 5px;
    padding: 15px;
    margin-bottom: 15px;
}
.broker-title { font-weight: bold; color: #2c3e50; margin-bottom: 10px; }
.offset {
    background-color: #fff;
    border: 1px solid #bdc3c7;
    padding: 5px;
    margin-bottom: 5px;
    border-radius: 3px;
    font-size: 0.9em;
}
.log-entry {
    background-color: #ecf0f1;
    padding: 5px;
    margin: 5px 0;
    border-radius: 3px;
    font-size: 0.9em;
}
.cluster-diagram {
    display: flex;
    flex-direction: column;
    align-items: center;
    background-color: #f8f9fa;
    border: 2px solid #dfe6e9;
    border-radius: 8px;
    padding: 20px;
    margin: 30px 0;
}
.cluster-box {
    border: 2px dashed #e74c3c;
    border-radius: 10px;
    padding: 20px;
    text-align: center;
    width: 90%;
}
.cluster-title { font-weight: bold; color: #c0392b; font-size: 1.2em; margin-bottom: 20px; }
.brokers-row { display: flex; justify-content: space-around; align-items: center; }
.cluster-actor { background: #fdedec; border: 1px solid #f5b7b1; }
.mini-broker {
    font-size: 0.9em;
    padding: 5px;
    background: #fff;
    border: 1px solid #ccc;
    border-radius: 4px;
}
.mini-broker.leader { border-color: #2980b9; font-weight: bold; background-color: #eaf5ff; }

/* ===== KAFKA — Flow step / Actor diagrams ===== */
.flow-step { display: flex; align-items: center; margin-bottom: 20px; }
.flow-actor {
    background-color: #eaf5ff;
    border: 1px solid #aed6f1;
    border-radius: 5px;
    padding: 10px 15px;
    font-weight: bold;
    text-align: center;
}
.flow-actor.cluster { background-color: #d5dbdb; border-color: #b2babb; }
.flow-actor.leader  { background-color: #d6eaf8; border-color: #85c1e9; }
.flow-label {
    position: absolute;
    top: -25px;
    left: 50%;
    transform: translateX(-50%);
    background-color: #fff;
    padding: 0 5px;
    font-size: 0.9em;
    white-space: nowrap;
}

/* ===== KAFKA — Consumer Group / Rebalance diagrams ===== */
.css-diagram-wrapper {
    background-color: #f8f9fa;
    border: 1px solid #dfe6e9;
    border-radius: 8px;
    padding: 20px;
    margin: 30px 0;
}
.css-diagram-wrapper h4 {
    text-align: center;
    margin-top: 0;
    margin-bottom: 15px;
    border-bottom: 1px solid #bdc3c7;
    padding-bottom: 10px;
}
.consumer-group-box {
    flex: 1;
    background-color: #fff;
    border: 2px dashed;
    border-radius: 8px;
    padding: 15px;
}
.consumer-group-box.group-a { border-color: #e082e0; }
.consumer-group-box.group-b { border-color: #a4a4f4; }
.consumer-assignment { margin-bottom: 10px; }
.assigned-partitions { margin-top: 8px; text-align: center; }
.partition-tag {
    display: inline-block;
    background-color: #eaf5ff;
    border: 1px solid #aed6f1;
    padding: 3px 8px;
    border-radius: 15px;
    font-size: 0.85em;
    margin: 2px;
}
.rebalance-diagram-wrapper {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 15px;
    background-color: #f8f9fa;
    border: 1px solid #dfe6e9;
    border-radius: 8px;
    padding: 20px;
    margin: 30px 0;
}
.rebalance-state {
    flex: 1;
    background-color: #fff;
    border: 1px solid #ddd;
    border-radius: 8px;
    padding: 15px;
}
.rebalance-state h4 {
    text-align: center;
    margin-top: 0;
    margin-bottom: 15px;
    border-bottom: 1px solid #bdc3c7;
    padding-bottom: 10px;
}
.consumer-node {
    background-color: #eaf5ff;
    border: 1px solid #aed6f1;
    border-radius: 5px;
    padding: 8px 12px;
    margin: 5px;
    font-weight: bold;
    text-align: center;
    display: inline-block;
}

/* ===== KAFKA — Metrics table ===== */
.metric-critical { background-color: #fadbd8; font-weight: bold; }
.metric-warning  { background-color: #fef9e7; }

/* ===== CASSANDRA — Ring / Hierarchy diagrams ===== */
.ring-diagram {
    position: relative;
    width: 300px;
    height: 300px;
    margin: 50px auto;
    border: 5px solid #bdc3c7;
    border-radius: 50%;
}
.ring-node {
    position: absolute;
    background-color: #3498db;
    color: white;
    border-radius: 50%;
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 0.85em;
}
.ring-center-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    font-weight: bold;
    color: #7f8c8d;
}
.hierarchy-diagram {
    background-color: #fff;
    padding: 20px;
    border-radius: 8px;
    margin: 30px 0;
    border: 1px solid #bdc3c7;
}
.hierarchy-diagram .label { font-weight: bold; display: block; margin-bottom: 5px; font-size: 0.9em; }
.dc-box { border: 2px solid #2980b9; padding: 15px; margin-top: 10px; border-radius: 5px; }
.dc-box .label { color: #2980b9; }
.rack-box { border: 2px dashed #8e44ad; padding: 15px; margin-top: 10px; border-radius: 4px; }
.rack-box .label { color: #8e44ad; }

/* ===== CASSANDRA — Data model / Partition diagrams ===== */
.partition-diagram {
    background-color: #fff;
    border: 1px solid #bdc3c7;
    border-radius: 8px;
    padding: 20px;
    margin: 20px 0;
}
.partition-diagram h4 { margin-top: 0; }
.partition { border: 2px solid #e67e22; border-radius: 5px; padding: 15px; margin-top: 10px; }
.partition-key  { font-weight: bold; color: #d35400; }
.partition-title { font-weight: bold; text-align: center; margin-bottom: 10px; color: #2980b9; }
.partition .row {
    display: flex;
    border: 1px solid #ecf0f1;
    background-color: #f9f9f9;
    margin-top: 5px;
    padding: 8px;
    border-radius: 3px;
}
.row .clustering-key { font-weight: bold; color: #2980b9; margin-right: 15px; min-width: 120px; }
.row .data { color: #7f8c8d; }
.partition-box { border: 1px solid #e67e22; padding: 5px 10px; border-radius: 10px; background-color: #fff9f2; font-size: 0.8em; display: inline-block; margin: 2px; }
.partition-box .label { color: #e67e22; margin: 0; }

/* ===== MONITORING — Architecture diagram ===== */
.arch-diagram {
    background-color: #fff;
    padding: 20px;
    border-radius: 8px;
    text-align: center;
    border: 1px solid #bdc3c7;
}
.arch-box { border: 2px solid #34495e; padding: 10px; border-radius: 5px; margin: 10px auto; max-width: 600px; }
.arch-component { background-color: #ecf0f1; border: 1px solid #bdc3c7; padding: 8px; margin: 5px; border-radius: 4px; display: inline-block; }
.diagram-box { background-color: #ecf0f1; border: 1px solid #bdc3c7; padding: 10px; border-radius: 5px; margin: 5px; display: inline-block; }

/* ===== CASSANDRA — CAP diagram ===== */
.cap-diagram {
    position: relative;
    width: 300px;
    height: 260px;
    margin: 40px auto;
}
.cap-circle {
    position: absolute;
    width: 150px;
    height: 150px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5em;
    font-weight: bold;
}
.cap-c { background-color: rgba(52, 152, 219, 0.7); top: 0; left: 75px; }
.cap-a { background-color: rgba(46, 204, 113, 0.7); bottom: 0; left: 20px; }
.cap-p { background-color: rgba(231, 76, 60, 0.7); bottom: 0; right: 20px; }
.cap-text { position: absolute; font-weight: bold; font-size: 1.2em; }
.text-cp { top: 115px; left: 190px; color: #2980b9; }
.text-ap { bottom: 55px; left: 140px; color: #27ae60; }
.text-ca { top: 115px; left: 80px; color: #c0392b; text-decoration: line-through; }