@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;600;800&display=swap');

:root {
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --bg-color: #0f172a;
    --text-color: #f8fafc;
    --card-bg: rgba(255, 255, 255, 0.05);
    --border-color: rgba(255, 255, 255, 0.1);
    --glass-blur: 20px;
    --accent: #818cf8;
    --success: #10b981;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Outfit', sans-serif;
}

html {
    overflow-x: hidden;
    width: 100%;
}

body {
    background: var(--bg-color);
    color: var(--text-color);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    align-items: center;
    padding: 40px 20px;
    position: relative;
    overflow-x: hidden;
    width: 100%;
    scroll-behavior: smooth;
}

/* Background Blobs */
.bg-blobs {
    position: absolute;
    width: 100%;
    height: 100%;
    z-index: -1;
}

.blob {
    position: absolute;
    width: 600px;
    height: 600px;
    background: var(--primary-gradient);
    filter: blur(80px);
    /* Reduced blur */
    border-radius: 50%;
    opacity: 0.12;
    will-change: transform;
}

.blob-1 {
    top: -10%;
    right: -10%;
}

.blob-2 {
    bottom: -10%;
    left: -10%;
    animation-delay: -5s;
}

@keyframes rotate {
    from {
        transform: rotate(0deg) translate(-5%, -5%);
    }

    to {
        transform: rotate(360deg) translate(-5%, -5%);
    }
}

/* Calculator Card */
.calculator-card {
    background: var(--card-bg);
    backdrop-filter: blur(var(--glass-blur));
    -webkit-backdrop-filter: blur(var(--glass-blur));
    border: 1px solid var(--border-color);
    border-radius: 28px;
    /* Slightly smaller radius */
    padding: 30px 35px;
    /* Reduced padding */
    width: 100%;
    max-width: 800px;
    /* Compacted from 900px */
    box-shadow: 0 30px 60px rgba(0, 0, 0, 0.4);
    will-change: transform, opacity;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

header {
    text-align: center;
    margin-bottom: 25px;
    /* Reduced from 35px */
}

header h1 {
    font-size: 2.5rem;
    font-weight: 800;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 10px;
}

header p {
    color: #94a3b8;
    font-size: 1rem;
}

/* Tabs */
.unit-tabs {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 8px;
    /* Slightly tighter gap */
    margin-bottom: 25px;
    width: 100%;
    max-width: 100%;
    overflow-x: hidden;
    /* Prevent horizontal scroll on this container */
}

/* Custom Scrollbar for Overlay */
.overlay-content::-webkit-scrollbar {
    width: 6px;
}

.overlay-content::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 10px;
}

.tab-btn {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border-color);
    padding: 8px 16px;
    /* Reduced from 10/20 */
    border-radius: 12px;
    color: #94a3b8;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    white-space: nowrap;
    font-size: 0.9rem;
    /* Slightly smaller text */
}

.tab-btn:hover {
    background: rgba(255, 255, 255, 0.08);
    color: white;
}

.tab-btn.active {
    background: var(--accent);
    color: #0f172a;
    border-color: var(--accent);
    box-shadow: 0 8px 20px rgba(129, 140, 248, 0.3);
}

/* Category Overlay */
.category-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(15px);
    -webkit-backdrop-filter: blur(15px);
    display: none;
    z-index: 2000;
    opacity: 0;
    transition: opacity 0.3s ease;
    overflow-y: auto;
    /* Allow scrolling of the overlay itself */
    padding: 20px;
    /* Space around the modal */
}

.category-overlay.active {
    display: flex;
    justify-content: center;
    align-items: flex-start;
    /* Start from top instead of center to prevent cutoff */
    opacity: 1;
}

.overlay-content {
    background: #1e293b;
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 24px;
    width: 100%;
    max-width: 800px;
    height: auto;
    padding: 25px;
    margin: auto 0;
    /* Vertically center within flex-start if there's room */
    transform: scale(0.9);
    transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    position: relative;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    display: block;
}

/* Ensure the header doesn't scroll away if we decide to make just the grid scrollable later, 
   but for now let the whole content scroll as it's simpler. */

.category-overlay.active .overlay-content {
    transform: scale(1);
}

.overlay-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.overlay-header h2 {
    font-size: 1.8rem;
    color: white;
}

.close-overlay {
    background: none;
    border: none;
    color: #94a3b8;
    font-size: 2.5rem;
    cursor: pointer;
    line-height: 1;
    transition: color 0.3s;
}

.close-overlay:hover {
    color: var(--accent);
}

.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
    /* Slightly narrower column */
    gap: 12px;
}

.category-item {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.05);
    border-radius: 16px;
    padding: 20px 15px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.category-item i {
    font-size: 1.5rem;
    color: var(--accent);
    opacity: 0.8;
}

.category-item span {
    font-weight: 600;
    font-size: 0.95rem;
    color: #cbd5e1;
}

.category-item:hover {
    background: rgba(129, 140, 248, 0.1);
    border-color: rgba(129, 140, 248, 0.3);
    transform: translateY(-5px);
}

.category-item.active {
    background: var(--accent);
    border-color: var(--accent);
}

.category-item.active span,
.category-item.active i {
    color: #0f172a;
}

.browse-btn {
    background: rgba(255, 255, 255, 0.05) !important;
    border: 1px dashed rgba(255, 255, 255, 0.2) !important;
    color: #94a3b8 !important;
}

.browse-btn:hover {
    border-color: var(--accent) !important;
    color: white !important;
}

/* Old Dropdown Removed */

/* Conversion Engine */
.conversion-engine {
    display: flex;
    align-items: center;
    gap: 20px;
    margin-bottom: 35px;
    /* Reduced from 50px */
}

.converter-block {
    flex: 1;
    background: rgba(15, 23, 42, 0.4);
    padding: 24px;
    border-radius: 20px;
    border: 1px solid var(--border-color);
    transition: transform 0.3s;
}

.converter-block:focus-within {
    transform: translateY(-2px);
    border-color: var(--accent);
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-bottom: 15px;
}

.input-group label {
    font-size: 0.8rem;
    font-weight: 700;
    color: #64748b;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.input-group input {
    background: transparent;
    border: none;
    color: white;
    font-size: 1.8rem;
    font-weight: 800;
    outline: none;
    width: 100%;
}

.select-wrapper {
    background: rgba(255, 255, 255, 0.05);
    border-radius: 12px;
    border: 1px solid var(--border-color);
}

.select-wrapper select {
    width: 100%;
    background: #1e293b;
    border: none;
    padding: 12px 15px;
    color: white;
    font-size: 1rem;
    font-weight: 600;
    outline: none;
    cursor: pointer;
    border-radius: 12px;
}

.swap-action button {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    color: white;
    width: 46px;
    /* Slightly smaller */
    height: 46px;
    border-radius: 50%;
    font-size: 1.4rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.swap-action button:hover {
    background: var(--accent);
    color: #0f172a;
    transform: rotate(180deg) scale(1.1);
    box-shadow: 0 0 20px rgba(129, 140, 248, 0.4);
}

.swap-action button:active {
    transform: rotate(180deg) scale(0.95);
}

/* Quick Results */
.quick-results-section h3 {
    font-size: 1.1rem;
    font-weight: 700;
    color: #94a3b8;
    margin-bottom: 20px;
    text-align: left;
    padding-left: 5px;
}

.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    /* Reduced to prevent horizontal push */
    gap: 12px;
}

.result-card {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.05);
    border-radius: 20px;
    padding: 20px;
    text-align: center;
    transition: all 0.3s;
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 8px;
}

.result-card:hover {
    background: rgba(255, 255, 255, 0.06);
    transform: scale(1.02);
}

.res-val {
    font-size: 1.1rem;
    font-weight: 800;
    color: var(--accent);
    word-break: break-all;
}

.res-unit {
    font-size: 0.8rem;
    font-weight: 600;
    color: #64748b;
}

/* Footer */
.card-footer {
    margin-top: 40px;
    text-align: center;
    border-top: 1px solid var(--border-color);
    padding-top: 30px;
}

.ghost-btn {
    background: transparent;
    border: none;
    color: #64748b;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.ghost-btn:hover {
    color: white;
}

/* Responsive */
@media (max-width: 768px) {
    .calculator-card {
        padding: 25px 15px;
    }

    .unit-tabs {
        gap: 6px;
    }

    .tab-btn {
        padding: 6px 12px;
        font-size: 0.8rem;
    }

    .conversion-engine {
        flex-direction: column;
        gap: 15px;
    }

    .swap-action button {
        transform: rotate(90deg);
    }

    .swap-action button:hover {
        transform: rotate(270deg);
    }

    .results-grid {
        grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    }

    .overlay-content {
        padding: 20px;
        width: 100%;
        border-radius: 0;
        /* Full screen feel on mobile */
        height: 100%;
        max-height: 100vh;
    }

    .category-grid {
        grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
    }
}