/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: #1a1a2e;
    background: #f8f9fa;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ===== Container ===== */
.container { max-width: 1100px; margin: 0 auto; padding: 0 1.5rem; }

/* ===== Breadcrumb ===== */
.breadcrumb {
    background: #f0f1f5;
    padding: 0.6rem 0;
    font-size: 0.85rem;
    border-bottom: 1px solid #e0e0e0;
}
.breadcrumb a {
    color: #1a1a2e;
    text-decoration: none;
    font-weight: 500;
}
.breadcrumb a:hover { color: #ffd166; }
.breadcrumb span { color: #888; }

/* ===== Highlight Box (Articles) ===== */
.highlight-box {
    background: #fffcf0;
    border-left: 4px solid #ffd166;
    padding: 1rem 1.25rem;
    margin: 1.5rem 0;
    border-radius: 0 8px 8px 0;
}
.highlight-box p { margin: 0; font-size: 0.9rem; color: #555; }

/* ===== Header ===== */
.header {
    background: #1a1a2e;
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 8px rgba(0,0,0,0.15);
}
.header .container { display: flex; align-items: center; justify-content: space-between; }
.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: #fff;
    text-decoration: none;
    letter-spacing: -0.5px;
}
.logo span { color: #ffd166; }
.nav { display: flex; gap: 1.5rem; }
.nav a {
    color: #ccc;
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    transition: color 0.2s;
}
.nav a:hover, .nav a.active { color: #ffd166; }

/* ===== Hero ===== */
.hero {
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
    color: #fff;
    padding: 4rem 0;
    text-align: center;
}
.hero h1 { font-size: 2.5rem; font-weight: 800; margin-bottom: 1rem; }
.hero p { font-size: 1.15rem; color: #b0b8d1; max-width: 650px; margin: 0 auto; line-height: 1.7; }

/* ===== Tools Grid ===== */
.tools-grid-section { padding: 3rem 0; }
.tools-grid-section h2 { text-align: center; font-size: 1.75rem; margin-bottom: 2rem; color: #1a1a2e; }
.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}
.tool-card {
    background: #fff;
    border-radius: 12px;
    padding: 1.75rem;
    text-decoration: none;
    color: inherit;
    box-shadow: 0 2px 8px rgba(0,0,0,0.06);
    transition: transform 0.2s, box-shadow 0.2s;
    position: relative;
    border: 1px solid #eee;
}
.tool-card:hover:not(.disabled) { transform: translateY(-3px); box-shadow: 0 8px 24px rgba(0,0,0,0.1); }
.tool-card.featured { border-color: #ffd166; background: #fffcf0; }
.tool-card.disabled { opacity: 0.6; cursor: default; }
.tool-icon { font-size: 2rem; margin-bottom: 0.75rem; }
.tool-card h3 { font-size: 1.15rem; font-weight: 700; margin-bottom: 0.5rem; }
.tool-card p { font-size: 0.9rem; color: #666; line-height: 1.5; }
.tool-tag {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: #ffd166;
    color: #1a1a2e;
    font-size: 0.75rem;
    font-weight: 700;
    padding: 0.2rem 0.6rem;
    border-radius: 4px;
}

/* ===== Benefits ===== */
.about-section { padding: 3rem 0; background: #fff; }
.about-section h2 { text-align: center; font-size: 1.75rem; margin-bottom: 2rem; }
.benefits { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 2rem; }
.benefit h3 { font-size: 1.1rem; font-weight: 700; margin-bottom: 0.5rem; color: #1a1a2e; }
.benefit p { font-size: 0.95rem; color: #555; line-height: 1.6; }

/* ===== Footer ===== */
.footer {
    margin-top: auto;
    background: #1a1a2e;
    color: #888;
    padding: 1.5rem 0;
    text-align: center;
    font-size: 0.85rem;
}

/* ===== Calculator Page ===== */
.calc-hero {
    background: linear-gradient(135deg, #1a1a2e 0%, #243b55 100%);
    color: #fff;
    padding: 2.5rem 0;
    text-align: center;
}
.calc-hero h1 { font-size: 2rem; font-weight: 800; margin-bottom: 0.5rem; }
.calc-hero p { color: #b0b8d1; font-size: 1rem; }

.calc-section { padding: 2.5rem 0; }
.calc-wrapper {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    align-items: start;
}
@media (max-width: 768px) {
    .calc-wrapper { grid-template-columns: 1fr; }
}

/* ===== Calculator Form ===== */
.calc-form {
    background: #fff;
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 2px 12px rgba(0,0,0,0.06);
    border: 1px solid #eee;
}
.calc-form h2 { font-size: 1.3rem; margin-bottom: 1.25rem; color: #1a1a2e; }
.form-group { margin-bottom: 1.25rem; }
.form-group label {
    display: block;
    font-weight: 600;
    font-size: 0.9rem;
    margin-bottom: 0.4rem;
    color: #333;
}
.form-group input, .form-group select {
    width: 100%;
    padding: 0.7rem 0.9rem;
    border: 1.5px solid #ddd;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.2s;
    background: #fafafa;
}
.form-group input:focus, .form-group select:focus {
    outline: none;
    border-color: #ffd166;
    background: #fff;
}
.form-group .unit-hint { font-size: 0.8rem; color: #888; margin-top: 0.2rem; }
.calc-btn {
    width: 100%;
    padding: 0.85rem;
    background: #ffd166;
    color: #1a1a2e;
    border: none;
    border-radius: 8px;
    font-size: 1.05rem;
    font-weight: 700;
    cursor: pointer;
    transition: background 0.2s;
}
.calc-btn:hover { background: #f0c04d; }
.reset-btn {
    width: 100%;
    padding: 0.6rem;
    margin-top: 0.6rem;
    background: transparent;
    color: #888;
    border: 1px solid #ddd;
    border-radius: 8px;
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.2s;
}
.reset-btn:hover { background: #f5f5f5; color: #333; }

/* ===== Results ===== */
.calc-results {
    background: #fff;
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 2px 12px rgba(0,0,0,0.06);
    border: 1px solid #eee;
}
.calc-results h2 { font-size: 1.3rem; margin-bottom: 1.25rem; color: #1a1a2e; }
.result-grid { display: grid; gap: 1rem; }
.result-item {
    background: #f8f9fa;
    border-radius: 8px;
    padding: 1rem 1.25rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.result-item .label { font-size: 0.9rem; color: #555; font-weight: 500; }
.result-item .value { font-size: 1.2rem; font-weight: 700; color: #1a1a2e; }
.result-item.highlight { background: #fffcf0; border: 1px solid #ffd166; }
.result-item.highlight .value { color: #1a1a2e; font-size: 1.4rem; }
.result-note { font-size: 0.85rem; color: #888; margin-top: 1rem; line-height: 1.5; }

/* ===== SEO Content ===== */
.content-section { padding: 3rem 0; background: #fff; }
.content-section h2 { font-size: 1.5rem; margin-bottom: 1rem; color: #1a1a2e; }
.content-section h3 { font-size: 1.15rem; margin: 1.5rem 0 0.75rem; color: #333; }
.content-section p { font-size: 0.95rem; color: #555; line-height: 1.7; margin-bottom: 1rem; }
.content-section ul { margin: 0 0 1rem 1.5rem; }
.content-section li { font-size: 0.95rem; color: #555; line-height: 1.7; margin-bottom: 0.3rem; }

.faq-item {
    margin-bottom: 1rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid #eee;
}
.faq-item:last-child { border-bottom: none; }
.faq-item h3 { font-size: 1.05rem; margin: 0 0 0.4rem 0; color: #1a1a2e; cursor: pointer; }
.faq-item p { font-size: 0.92rem; color: #555; }

/* ===== Comparison Table ===== */
.comparison-table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
    font-size: 0.9rem;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 1px 6px rgba(0,0,0,0.06);
}
.comparison-table thead {
    background: #1a1a2e;
    color: #fff;
}
.comparison-table th {
    padding: 0.75rem 0.8rem;
    text-align: left;
    font-weight: 600;
    font-size: 0.85rem;
}
.comparison-table td {
    padding: 0.7rem 0.8rem;
    border-bottom: 1px solid #eee;
    color: #444;
}
.comparison-table tbody tr:hover {
    background: #f8f9fa;
}
.comparison-table tbody tr:last-child td {
    border-bottom: none;
}
@media (max-width: 768px) {
    .comparison-table { font-size: 0.8rem; }
    .comparison-table th,
    .comparison-table td { padding: 0.5rem 0.4rem; }
}

/* ===== Responsive ===== */
@media (max-width: 600px) {
    .hero h1 { font-size: 1.75rem; }
    .hero { padding: 2.5rem 0; }
    .tools-grid { grid-template-columns: 1fr; }
    .header .container { flex-direction: column; gap: 0.75rem; }
}