/* 
   UNIT CONVERTER - EXPERT WEB TOOLS
   Theme: 2025 Glassmorphism (Command Center)
*/

/* --- Fonts --- */
@font-face { font-family: 'Inter'; src: url('/fonts/inter-v20-latin-regular.woff2') format('woff2'); font-weight: 400; font-display: swap; }
@font-face { font-family: 'Orbitron'; src: url('/fonts/orbitron-v35-latin-700.woff2') format('woff2'); font-weight: 700; font-display: swap; }
@font-face { font-family: 'Roboto Mono'; src: url('/fonts/roboto-mono-v31-latin-regular.woff2') format('woff2'); font-weight: 400; font-display: swap; }

:root {
    --bg-dark: #0a0a0f;
    --primary-accent: #3b82f6;
    --secondary-accent: #8b5cf6;
    --text-main: #ffffff;
    --text-muted: #94a3b8;
    --card-bg: rgba(25, 25, 35, 0.6);
    --card-border: rgba(255, 255, 255, 0.08);
    --input-bg: rgba(255, 255, 255, 0.05);
    
    --font-heading: 'Orbitron', sans-serif;
    --font-body: 'Inter', sans-serif;
    --font-code: 'Roboto Mono', monospace;
}

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

body {
    background-color: var(--bg-dark);
    color: var(--text-main);
    font-family: var(--font-body);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.background-glow {
    position: fixed;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at center, rgba(59, 130, 246, 0.08) 0%, rgba(10, 10, 15, 0) 50%);
    z-index: -1;
    pointer-events: none;
}

/* --- Header --- */
.tool-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 5%;
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
}
.back-btn {
    color: var(--text-muted);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: color 0.3s;
}
.back-btn:hover { color: var(--primary-accent); }
.logo { font-family: var(--font-heading); font-size: 1.2rem; }
.logo span { color: var(--primary-accent); }

/* --- Main Layout --- */
.main-content {
    flex-grow: 1;
    padding: 2rem 5%;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
    min-height: 600px;
}

.tool-layout {
    display: grid;
    grid-template-columns: 260px 1fr;
    gap: 2rem;
    height: 100%;
}

/* Sidebar */
.category-sidebar {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.search-wrapper {
    position: relative;
    width: 100%;
}
.search-wrapper i {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
}
#categorySearch {
    width: 100%;
    padding: 12px 12px 12px 40px;
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 8px;
    color: #fff;
    font-size: 0.9rem;
    outline: none;
}
#categorySearch:focus { border-color: var(--primary-accent); }

.nav-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 8px;
    overflow-y: auto;
    max-height: 70vh;
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: 12px;
    background: transparent;
    border: 1px solid transparent;
    color: var(--text-muted);
    padding: 12px 16px;
    border-radius: 8px;
    cursor: pointer;
    text-align: left;
    font-size: 0.95rem;
    transition: all 0.2s;
    font-weight: 500;
}
.nav-btn:hover { background: rgba(255,255,255,0.03); color: #fff; }
.nav-btn.active {
    background: rgba(59, 130, 246, 0.1);
    border-color: rgba(59, 130, 246, 0.3);
    color: var(--primary-accent);
}
.nav-btn i { width: 20px; text-align: center; }

/* Display Area */
.converter-display {
    display: flex;
    align-items: flex-start;
    justify-content: center;
}

.converter-card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 16px;
    padding: 2.5rem;
    width: 100%;
    max-width: 600px;
    backdrop-filter: blur(10px);
    opacity: 0;
    transform: translateY(10px);
    transition: opacity 0.3s ease, transform 0.3s ease;
    display: none; /* JS toggles 'display: block' */
}

.converter-card.active {
    display: block;
    opacity: 1;
    transform: translateY(0);
}

.card-header {
    margin-bottom: 2rem;
    border-bottom: 1px solid var(--card-border);
    padding-bottom: 1rem;
}
.card-header h2 {
    font-family: var(--font-heading);
    font-size: 1.4rem;
    color: var(--text-main);
    display: flex;
    align-items: center;
    gap: 12px;
}
.card-header h2 i { color: var(--secondary-accent); }

/* Conversion Inputs */
.conversion-body {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
}
.input-group label {
    font-size: 0.85rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
}

input[type="number"], select {
    width: 100%;
    background-color: var(--input-bg);
    border: 1px solid var(--card-border);
    color: #fff;
    padding: 14px;
    border-radius: 8px;
    font-size: 1.1rem;
    outline: none;
    font-family: var(--font-code);
}
input[type="number"]:focus, select:focus { border-color: var(--primary-accent); }

select option {
    background-color: var(--bg-dark);
    color: #fff;
    padding: 10px;
}

.swap-btn {
    background: transparent;
    border: 1px solid var(--card-border);
    color: var(--text-muted);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    cursor: pointer;
    align-self: center;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    transition: all 0.2s;
    margin: 0.5rem 0;
}
.swap-btn:hover {
    background: rgba(255,255,255,0.1);
    color: #fff;
    transform: rotate(180deg);
}

.hidden { display: none !important; }

footer { text-align: center; padding: 3rem 0; color: var(--text-muted); font-size: 0.9rem; border-top: 1px solid var(--card-border); margin-top: 3rem; }
footer a { color: #fff; text-decoration: none; }

/* Responsive */
@media (max-width: 800px) {
    .tool-layout { grid-template-columns: 1fr; gap: 1rem; }
    .category-sidebar { display: grid; grid-template-columns: 1fr; }
    .nav-grid { display: flex; overflow-x: auto; gap: 10px; padding-bottom: 10px; max-height: none; }
    .nav-btn { flex: 0 0 auto; padding: 10px 16px; white-space: nowrap; }
    .converter-card { padding: 1.5rem; }
}