:root {
    /* Global Colors */
    --bg-main: #050505;
    --glass-bg: rgba(20, 20, 20, 0.7);
    --glass-border: rgba(255, 255, 255, 0.08);
    --text-primary: #FFFFFF;
    --text-secondary: #8b949e;
    
    /* Dynamic Accent (Changes via JS) */
    --accent: #3B82F6; 
    --accent-glow: rgba(59, 130, 246, 0.4);

    /* UI Components */
    --input-bg: rgba(0, 0, 0, 0.3);
    --surface: #161b22;
    
    --font-heading: 'Unbounded', sans-serif;
    --font-body: 'Inter', sans-serif;
    --ease: cubic-bezier(0.25, 1, 0.5, 1);
}

* { box-sizing: border-box; margin: 0; padding: 0; outline: none; -webkit-tap-highlight-color: transparent; }

body {
    font-family: var(--font-body);
    background-color: var(--bg-main);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex; justify-content: center;
    overflow-x: hidden;
}

/* Background */
.ambient-bg { position: fixed; width: 100%; height: 100%; z-index: -1; pointer-events: none; }
.orb { position: absolute; border-radius: 50%; filter: blur(120px); opacity: 0.25; }
.orb-1 { top: -10%; left: -10%; width: 60vw; height: 60vw; background: radial-gradient(circle, var(--accent) 0%, transparent 60%); transition: 1s ease; }
.orb-2 { bottom: -10%; right: -10%; width: 50vw; height: 50vw; background: radial-gradient(circle, #5b21b6 0%, transparent 60%); }

.layout {
    width: 100%; max-width: 460px; padding: 20px;
    display: flex; flex-direction: column; gap: 20px; z-index: 10;
}

/* HEADER */
.top-bar {
    display: flex; align-items: center; padding: 16px 20px;
    background: var(--glass-bg); backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border); border-radius: 20px;
}
.header-left { display: flex; align-items: center; gap: 16px; width: 100%; }
.back-btn {
    width: 36px; height: 36px; display: flex; align-items: center; justify-content: center;
    background: rgba(255,255,255,0.05); border-radius: 10px; color: var(--text-secondary);
    transition: 0.2s; text-decoration: none;
}
.back-btn:hover { background: rgba(255,255,255,0.1); color: var(--text-primary); }

.brand { display: flex; align-items: center; gap: 10px; }
.logo-mark {
    width: 32px; height: 32px; background: linear-gradient(135deg, var(--accent), #2563EB);
    border-radius: 8px; display: flex; align-items: center; justify-content: center;
    box-shadow: 0 0 20px var(--accent-glow); color: white; font-size: 14px; transition: 0.3s;
}
.logo-text { font-family: var(--font-heading); font-size: 16px; font-weight: 700; letter-spacing: -0.5px; }
.logo-text span { color: var(--accent); transition: 0.3s; }

/* NAV */
.category-nav {
    background: var(--glass-bg); padding: 5px; border-radius: 16px;
    border: 1px solid var(--glass-border); backdrop-filter: blur(20px);
}
.nav-track { display: flex; gap: 5px; overflow-x: auto; }
.nav-item {
    flex: 1; padding: 10px; background: transparent; border: none; border-radius: 12px;
    color: var(--text-secondary); font-family: var(--font-heading); font-size: 11px;
    font-weight: 700; text-transform: uppercase; cursor: pointer; transition: 0.3s;
}
.nav-item:hover { color: var(--text-primary); }
.nav-item.active { background: var(--surface); color: var(--accent); box-shadow: 0 2px 10px rgba(0,0,0,0.1); }

/* CONVERTER CARD */
.converter-card {
    background: var(--glass-bg); padding: 24px; border-radius: 24px;
    border: 1px solid var(--glass-border); backdrop-filter: blur(20px);
}

.field-group { margin-bottom: 5px; }
.field-group label {
    display: block; font-size: 11px; color: var(--text-secondary);
    text-transform: uppercase; font-weight: 700; margin-bottom: 10px; padding-left: 5px;
}

.input-wrapper {
    background: var(--input-bg); border: 1px solid var(--glass-border);
    border-radius: 16px; padding: 6px; display: flex; align-items: center;
    transition: 0.3s;
}
.input-wrapper:focus-within { border-color: var(--accent); box-shadow: 0 0 0 2px var(--accent-glow); }

input {
    flex: 1; background: transparent; border: none; padding: 10px 15px;
    color: var(--text-primary); font-family: var(--font-heading); font-size: 24px;
    font-weight: 600; width: 100%;
}
input::placeholder { color: rgba(255,255,255,0.1); }

/* CUSTOM SELECT */
.custom-select { position: relative; min-width: 120px; max-width: 160px; }
select {
    appearance: none; -webkit-appearance: none;
    width: 100%; padding: 12px 35px 12px 15px;
    background: rgba(255,255,255,0.05); border: 1px solid rgba(255,255,255,0.05);
    border-radius: 12px; color: var(--text-primary);
    font-family: var(--font-body); font-size: 13px; font-weight: 600;
    cursor: pointer; transition: 0.2s;
    text-overflow: ellipsis; white-space: nowrap; overflow: hidden;
}
select:hover { background: rgba(255,255,255,0.1); }
select option { background: #1C1C1E; color: white; padding: 10px; }
.caret {
    position: absolute; right: 12px; top: 50%; transform: translateY(-50%);
    font-size: 10px; color: var(--text-secondary); pointer-events: none;
}

.target-label { padding-left: 15px; font-size: 14px; color: var(--text-secondary); flex: 1; }

/* SWAP */
.swap-zone { display: flex; align-items: center; gap: 15px; margin: 20px 0; }
.divider { flex: 1; height: 1px; background: var(--glass-border); }
.swap-btn {
    width: 44px; height: 44px; border-radius: 50%; background: var(--surface);
    border: 1px solid var(--glass-border); color: var(--accent);
    cursor: pointer; display: flex; align-items: center; justify-content: center;
    transition: 0.3s var(--ease); font-size: 16px;
}
.swap-btn:hover {
    background: var(--accent); color: white;
    transform: rotate(180deg); box-shadow: 0 0 15px var(--accent-glow);
}

/* RESULT */
.result-box {
    margin-top: 25px; padding: 25px; border-radius: 20px;
    background: linear-gradient(135deg, rgba(255,255,255,0.05) 0%, rgba(255,255,255,0.01) 100%);
    border: 1px solid var(--glass-border); text-align: center;
    position: relative; overflow: hidden; cursor: pointer; transition: 0.2s;
}
.result-box:hover { border-color: var(--accent); background: rgba(255,255,255,0.03); }
.result-box:active { transform: scale(0.98); }

/* Glow effect inside result */
.result-box::before {
    content: ''; position: absolute; top: -50%; left: -50%; width: 200%; height: 200%;
    background: radial-gradient(circle, var(--accent-glow) 0%, transparent 50%);
    opacity: 0.2; pointer-events: none;
}

.res-title { font-size: 10px; text-transform: uppercase; font-weight: 700; color: var(--text-secondary); margin-bottom: 10px; position: relative; }
.res-value {
    font-family: var(--font-heading); font-size: 42px; font-weight: 700;
    line-height: 1.1; margin-bottom: 5px; color: var(--text-primary);
    position: relative; word-break: break-all;
}
.res-unit { font-size: 14px; font-weight: 500; color: var(--accent); position: relative; }
.copy-indicator {
    margin-top: 15px; font-size: 11px; color: var(--text-secondary); opacity: 0;
    transition: 0.2s; transform: translateY(5px); position: relative;
}
.result-box:hover .copy-indicator { opacity: 1; transform: translateY(0); }

/* TOAST */
.toast {
    position: fixed; bottom: 30px; left: 50%; transform: translate(-50%, 50px);
    background: #10B981; color: white; padding: 10px 20px; border-radius: 50px;
    font-size: 13px; font-weight: 600; display: flex; align-items: center; gap: 8px;
    box-shadow: 0 10px 30px rgba(16, 185, 129, 0.3); opacity: 0; transition: 0.4s;
}
.toast.show { opacity: 1; transform: translate(-50%, 0); }