:root {
    --primary-hue: 250;
    --accent-hue: 330;
    --bg-dark: #0f172a;
    --glass-bg: rgba(30, 41, 59, 0.85);
    --glass-border: rgba(255, 255, 255, 0.08);
    --glass-highlight: rgba(255, 255, 255, 0.15);
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --accent-color: hsl(var(--primary-hue), 90%, 65%);
    --accent-gradient: linear-gradient(135deg, hsl(var(--primary-hue), 80%, 60%), hsl(var(--accent-hue), 80%, 60%));
    --animation-speed: 0.3s;
}

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

body {
    background-color: var(--bg-dark);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    flex-direction: row;
    /* Default: Side by Side */
    justify-content: center;
    align-items: flex-start;
    overflow-x: hidden;
    position: relative;
    padding: 4rem;
    gap: 4rem;
}

/* Background Animation */
.background-blobs {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
    filter: blur(80px);
}

.blob {
    position: absolute;
    border-radius: 50%;
    opacity: 0.4;
    animation: blob-bounce 20s infinite alternate;
}

.blob-1 {
    width: 50vw;
    height: 50vw;
    background: hsl(var(--primary-hue), 60%, 40%);
    top: -10%;
    left: -10%;
}

.blob-2 {
    width: 40vw;
    height: 40vw;
    background: hsl(var(--accent-hue), 60%, 40%);
    bottom: -10%;
    right: -10%;
    animation-delay: -5s;
}

.blob-3 {
    width: 30vw;
    height: 30vw;
    background: #0ea5e9;
    top: 40%;
    left: 40%;
    animation-delay: -10s;
}

@keyframes blob-bounce {
    0% {
        transform: translate(0, 0);
    }

    100% {
        transform: translate(50px, 50px);
    }
}

/* Main App Container */
.main-app {
    width: 100%;
    max-width: 500px;
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: 28px;
    padding: 2rem;
    box-shadow: 0 30px 60px -12px rgba(0, 0, 0, 0.6);
}

.app-header {
    text-align: center;
    margin-bottom: 2rem;
}

.app-header h1 {
    font-size: 2rem;
    font-weight: 700;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.app-header p {
    color: var(--text-muted);
    font-size: 0.95rem;
}

/* Section Blocks */
.section-block {
    margin-bottom: 1.8rem;
}

.section-block h3 {
    font-size: 0.95rem;
    color: #fff;
    margin-bottom: 0.8rem;
    font-weight: 600;
}

/* Toggle Switch */
.toggle-switch-container {
    display: flex;
    background: rgba(0, 0, 0, 0.3);
    padding: 4px;
    border-radius: 12px;
}

.toggle-btn {
    flex: 1;
    border: none;
    background: transparent;
    color: var(--text-muted);
    padding: 10px;
    font-weight: 600;
    cursor: pointer;
    border-radius: 10px;
    transition: all 0.2s;
    text-transform: capitalize;
}

.toggle-btn.active {
    background: var(--glass-highlight);
    color: #fff;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
}

/* Shape Nav */
.shape-nav {
    display: flex;
    gap: 10px;
    overflow-x: auto;
    scrollbar-width: none;
    mask-image: linear-gradient(to right, black 90%, transparent 100%);
}

.shape-btn {
    min-width: 80px;
    background: rgba(0, 0, 0, 0.1);
    border: 1px solid var(--glass-border);
    padding: 12px 0;
    border-radius: 14px;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    color: var(--text-muted);
    transition: all 0.2s;
}

.shape-btn.active {
    background: var(--accent-gradient);
    color: #fff;
    border-color: transparent;
    box-shadow: 0 5px 15px rgba(var(--primary-hue), 50%, 50%, 0.4);
}

.shape-btn .icon-box ion-icon {
    font-size: 1.4rem;
}

.shape-btn span {
    font-size: 0.75rem;
    font-weight: 500;
}

/* Inputs */
.inputs-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.input-group.full-width {
    grid-column: span 2;
}

.input-group label {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

.input-wrapper input {
    width: 100%;
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid var(--glass-border);
    padding: 12px 14px;
    border-radius: 10px;
    color: #fff;
    outline: none;
    font-size: 1rem;
    padding-right: 40px;
    transition: border 0.2s;
}

.input-wrapper input:focus {
    border-color: var(--accent-color);
}

.unit {
    position: absolute;
    right: 12px;
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* Ratio Selector */
.ratio-selector {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.ratio-btn {
    flex: 1;
    min-width: 60px;
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid var(--glass-border);
    color: var(--text-muted);
    padding: 10px;
    border-radius: 20px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.2s;
}

.ratio-btn.active {
    background: var(--accent-color);
    color: #fff;
    border-color: transparent;
}

.custom-ratio-wrapper {
    display: flex;
    align-items: center;
    gap: 5px;
    background: rgba(0, 0, 0, 0.2);
    padding: 4px 8px;
    border-radius: 20px;
    border: 1px solid var(--glass-border);
}

.custom-ratio-wrapper input {
    width: 30px;
    background: transparent;
    border: none;
    color: #fff;
    text-align: center;
    font-weight: 600;
    outline: none;
}

.custom-ratio-wrapper span {
    color: var(--text-muted);
}

/* Advanced Settings Toggle */
.advanced-settings {
    margin-top: 1rem;
}

.toggle-settings {
    background: none;
    border: none;
    color: var(--text-muted);
    font-size: 0.8rem;
    display: flex;
    align-items: center;
    gap: 6px;
    cursor: pointer;
}

.settings-content {
    margin-top: 8px;
    padding: 10px;
    background: rgba(0, 0, 0, 0.2);
    border-radius: 8px;
    display: flex;
    gap: 10px;
}

.settings-content.hidden {
    display: none;
}

.setting-group {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.setting-group label {
    font-size: 0.7rem;
    color: var(--text-muted);
}

.setting-group input {
    background: transparent;
    border: none;
    border-bottom: 1px solid #555;
    color: #fff;
    width: 60px;
    padding: 2px;
}

/* Results */
.results-card {
    background: rgba(255, 255, 255, 0.03);
    border-radius: 20px;
    padding: 1.5rem;
    border: 1px solid var(--glass-border);
}

.result-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.result-header h3 {
    font-size: 0.9rem;
    color: var(--text-muted);
}

.unit-select-wrapper {
    position: relative;
}

.unit-select {
    appearance: none;
    background: rgba(0, 0, 0, 0.4);
    border: 1px solid var(--glass-border);
    color: var(--accent-color);
    padding: 5px 10px;
    padding-right: 25px;
    border-radius: 8px;
    cursor: pointer;
}

.select-arrow {
    position: absolute;
    right: 8px;
    top: 8px;
    color: var(--accent-color);
    pointer-events: none;
}

.primary-result {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
}

.result-item {
    flex: 1;
    background: rgba(0, 0, 0, 0.2);
    padding: 1rem;
    border-radius: 12px;
    text-align: center;
}

.result-item.secondary {
    opacity: 0.7;
    transform: scale(0.95);
}

.result-item .label {
    font-size: 0.75rem;
    display: block;
    margin-bottom: 4px;
    color: var(--text-muted);
}

.result-item .value {
    font-size: 1.6rem;
    font-weight: 700;
    color: #fff;
}

.result-item .value small {
    font-size: 0.9rem;
    color: var(--text-muted);
    font-weight: 400;
}

.ratio-breakdown {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.8rem;
    background: rgba(0, 0, 0, 0.2);
    border-radius: 12px;
}

.part-card {
    display: flex;
    flex-direction: column;
}

.part-card.part-b {
    text-align: right;
}

.part-label {
    font-size: 0.7rem;
    text-transform: uppercase;
    color: var(--text-muted);
    margin-bottom: 2px;
}

.part-value {
    font-size: 1.1rem;
    font-weight: 600;
    color: #fff;
}

.separator {
    font-size: 1.2rem;
    color: var(--text-muted);
}

/* Instructions (Right Side 50%) */
.how-to-use {
    flex: 1;
    max-width: 500px;
    width: 100%;
    margin-top: 0;
    padding: 0;
}

.how-to-use h2 {
    text-align: center;
    margin-bottom: 2rem;
    font-size: 1.6rem;
    letter-spacing: 1px;
    text-transform: uppercase;
    color: var(--text-muted);
}

.steps-container {
    display: flex;
    flex-direction: column;
    /* Vertical List */
    gap: 1.5rem;
}

.step {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--glass-border);
    padding: 1.5rem;
    border-radius: 16px;
    text-align: left;
    transition: transform 0.2s;
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: 1.5rem;
}

.step:hover {
    background: rgba(255, 255, 255, 0.05);
    transform: translateY(-5px);
}

.step-number {
    min-width: 40px;
    height: 40px;
    background: var(--accent-gradient);
    color: #fff;
    border-radius: 50%;
    font-size: 1.2rem;
    font-weight: bold;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 10px rgba(var(--primary-hue), 50%, 50%, 0.4);
    margin-bottom: 0;
    flex-shrink: 0;
}

.step p {
    font-size: 0.95rem;
    color: var(--text-muted);
    line-height: 1.5;
}

.step strong {
    color: #fff;
    display: block;
    font-size: 1.1rem;
    margin-bottom: 0.3rem;
}

/* Mobile Optimization */
@media (max-width: 900px) {
    body {
        flex-direction: column;
        align-items: center;
        padding: 2rem 1rem;
    }

    .how-to-use {
        max-width: 100%;
        margin-top: 2rem;
    }

    .step {
        /* Keep vertical row layout on mobile too, looks nice */
    }
}