:root {
    /* Dark Theme (Default) */
    --bg-color: #0f172a;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    
    --calc-bg: rgba(30, 41, 59, 0.7);
    --calc-border: rgba(255, 255, 255, 0.1);
    --calc-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5), inset 0 1px 0 rgba(255, 255, 255, 0.1);
    
    --btn-bg: rgba(255, 255, 255, 0.05);
    --btn-hover: rgba(255, 255, 255, 0.1);
    --btn-active: rgba(255, 255, 255, 0.15);
    --btn-border: rgba(255, 255, 255, 0.05);
    
    --btn-action-text: #38bdf8;
    --btn-operator-bg: rgba(56, 189, 248, 0.15);
    --btn-operator-text: #38bdf8;
    --btn-equal-bg: #38bdf8;
    --btn-equal-text: #0f172a;
    
    --blob-1: #3b82f6;
    --blob-2: #8b5cf6;
    --calc-accent: #38bdf8;
    
    color-scheme: dark;
    accent-color: var(--calc-accent);
}

[data-theme="light"] {
    --bg-color: #f1f5f9;
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    
    --calc-bg: rgba(255, 255, 255, 0.7);
    --calc-border: rgba(255, 255, 255, 1);
    --calc-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.1), inset 0 1px 0 rgba(255, 255, 255, 0.5);
    
    --btn-bg: rgba(0, 0, 0, 0.03);
    --btn-hover: rgba(0, 0, 0, 0.06);
    --btn-active: rgba(0, 0, 0, 0.1);
    --btn-border: rgba(255, 255, 255, 0.5);
    
    --btn-action-text: #0ea5e9;
    --btn-operator-bg: rgba(14, 165, 233, 0.1);
    --btn-operator-text: #0ea5e9;
    --btn-equal-bg: #0ea5e9;
    --btn-equal-text: #ffffff;
    
    --blob-1: #60a5fa;
    --blob-2: #a78bfa;
    --calc-accent: #0ea5e9;
    
    color-scheme: light;
    accent-color: var(--calc-accent);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Outfit', sans-serif;
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
    -webkit-tap-highlight-color: transparent;
}

body {
    background-color: var(--bg-color);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    overflow-x: hidden;
    overflow-y: auto;
    padding: 20px 10px;
}

/* Background Blobs for Glassmorphism Effect */
.background-elements {
    position: absolute;
    width: 100%;
    height: 100%;
    z-index: 0;
    overflow: hidden;
}

.blob {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.6;
    animation: float 10s infinite alternate ease-in-out;
    translate: calc(var(--mouse-x, 0) * var(--move-factor, 30px)) calc(var(--mouse-y, 0) * var(--move-factor, 30px));
    transition: translate 0.5s ease-out;
}

.blob-1 {
    top: 20%;
    left: 25%;
    width: 300px;
    height: 300px;
    background-color: var(--blob-1);
    animation-delay: 0s;
    --move-factor: -60px;
}

.blob-2 {
    bottom: 20%;
    right: 25%;
    width: 400px;
    height: 400px;
    background-color: var(--blob-2);
    animation-delay: -5s;
    --move-factor: 80px;
}

@keyframes float {
    0% { transform: translate(0, 0) scale(1); }
    100% { transform: translate(30px, -50px) scale(1.1); }
}

.calculator-wrapper {
    position: relative;
    z-index: 10;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
}

/* Top Controls (Theme & Sound) */
.top-controls {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    max-width: 340px;
    padding: 0 10px;
}

.sound-btn {
    background-color: var(--calc-bg);
    border: 1px solid var(--calc-border);
    color: var(--text-primary);
    width: 40px;
    height: 30px;
    border-radius: 15px;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    transition: all 0.3s ease;
    touch-action: manipulation;
}

@media (hover: hover) {
    .sound-btn:hover {
        background-color: var(--btn-hover);
    }
}

.sound-btn.muted i {
    color: var(--text-secondary);
}

.sound-btn i {
    font-size: 14px;
    color: #38bdf8;
    transition: color 0.3s ease;
}

/* Theme Toggle */
.theme-toggle {
    display: flex;
    align-items: center;
}

.theme-switch-input {
    display: none;
}

.theme-switch-label {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 68px;
    height: 34px;
    background-color: var(--btn-bg);
    border-radius: 50px;
    position: relative;
    padding: 0 10px;
    cursor: pointer;
    box-shadow: inset 0 2px 6px rgba(0,0,0,0.2);
    border: 1px solid var(--btn-border);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.theme-switch-label i {
    font-size: 13px;
    z-index: 2;
    transition: color 0.4s ease, transform 0.4s ease;
}

/* Default (Dark Mode - unchecked) - ball is on left over Moon */
.fa-moon {
    color: var(--bg-color); /* Contrast with the white ball */
}
.fa-sun {
    color: var(--text-secondary); /* Faded out */
}

/* Light Mode (checked) - ball is on right over Sun */
.theme-switch-input:checked + .theme-switch-label .fa-moon {
    color: var(--text-secondary); /* Faded out */
}
.theme-switch-input:checked + .theme-switch-label .fa-sun {
    color: #ffffff; /* Contrast with the blue ball */
}

.toggle-ball {
    position: absolute;
    top: 3px;
    left: 4px;
    width: 26px;
    height: 26px;
    background-color: var(--text-primary);
    border-radius: 50%;
    transition: transform 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275), background-color 0.4s ease;
    z-index: 1;
    box-shadow: 0 2px 5px rgba(0,0,0,0.3);
}

.theme-switch-input:checked + .theme-switch-label .toggle-ball {
    transform: translateX(32px);
    background-color: #38bdf8; /* Vibrant blue for light mode */
}

/* Calculator Glassmorphism Container */
.calculator {
    width: 340px;
    background: var(--calc-bg);
    border-radius: 30px;
    padding: 30px 25px;
    box-shadow: var(--calc-shadow);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--calc-border);
    transition: width 0.4s cubic-bezier(0.4, 0, 0.2, 1), transform 0.1s ease-out, background 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
    transform-style: preserve-3d;
}

.calculator.scientific-mode {
    width: 680px;
}

.mode-toggle-container {
    display: flex;
    justify-content: space-between;
    margin-bottom: 15px;
    transform: translateZ(20px);
}

.mode-toggle-btn {
    background: var(--btn-bg);
    color: var(--text-primary);
    border: 1px solid var(--btn-border);
    padding: 8px 16px;
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.3s;
    backdrop-filter: blur(10px);
}

.mode-toggle-btn:hover {
    background: var(--btn-hover);
}

.mode-toggle-btn.active {
    background: #38bdf8;
    color: #0f172a;
    border-color: #38bdf8;
}

.angle-toggle {
    display: flex;
    background: var(--btn-bg);
    border-radius: 20px;
    overflow: hidden;
    border: 1px solid var(--btn-border);
}

.angle-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    padding: 8px 12px;
    cursor: pointer;
    font-size: 0.8rem;
    transition: all 0.3s;
}

.angle-btn.active {
    background: var(--btn-active);
    color: var(--text-primary);
}

.display {
    width: 100%;
    text-align: right;
    margin-bottom: 25px;
    min-height: 90px;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    word-wrap: break-word;
    word-break: break-all;
    padding: 0 10px;
    transform: translateZ(20px); /* Pops out slightly in 3D */
}

.previous-operand {
    color: var(--text-secondary);
    font-size: 1.2rem;
    min-height: 1.5rem;
    margin-bottom: 5px;
}

.current-operand {
    color: var(--text-primary);
    font-size: 3rem;
    font-weight: 500;
    line-height: 1;
    transition: font-size 0.2s ease;
}

.keypad-wrapper {
    display: flex;
    gap: 15px;
    transform: translateZ(30px);
    overflow: hidden;
}

.keypad {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 10px;
    flex-shrink: 0;
    width: 100%;
}

.scientific-keypad {
    display: none;
    width: calc(50% - 7.5px);
}

.calculator.scientific-mode .scientific-keypad {
    display: grid;
}

.calculator.scientific-mode .basic-keypad {
    width: calc(50% - 7.5px);
}

.btn {
    border: none;
    outline: none;
    background: var(--btn-bg);
    color: var(--text-primary);
    font-size: 1.5rem;
    font-weight: 400;
    border-radius: 16px;
    cursor: pointer;
    height: 60px;
    display: flex;
    justify-content: center;
    align-items: center;
    border: 1px solid var(--btn-border);
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    user-select: none;
    position: relative;
    overflow: hidden;
    touch-action: manipulation;
}

/* Glass Shine Effect on Hover */
.btn::after {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: linear-gradient(to bottom right, rgba(255,255,255,0) 0%, rgba(255,255,255,0.1) 50%, rgba(255,255,255,0) 100%);
    transform: rotate(45deg) translate(-100%, 100%);
    transition: transform 0.6s ease;
}

@media (hover: hover) {
    .btn:hover::after {
        transform: rotate(45deg) translate(100%, -100%);
    }

    .btn:hover {
        background: var(--btn-hover);
        transform: translateY(-2px);
        box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    }
    
    .btn-operator:hover {
        background: var(--btn-operator-bg);
        filter: brightness(1.1);
    }
    
    .btn-equal:hover {
        background: var(--btn-equal-bg);
        filter: brightness(1.1);
        box-shadow: 0 10px 25px rgba(56, 189, 248, 0.4);
    }
}

.btn:active, .btn.simulate-active {
    background: var(--btn-active);
    transform: translateY(1px) scale(0.95);
    box-shadow: none;
    transition: all 0.1s;
}

.btn-action {
    color: var(--btn-action-text);
    font-weight: 500;
}

.btn-operator {
    background: var(--btn-operator-bg);
    color: var(--btn-operator-text);
    font-size: 1.5rem;
    font-weight: 500;
}

.btn-sci {
    color: var(--text-secondary);
    font-size: 1.1rem;
    font-weight: 400;
}

.btn-equal {
    background: var(--btn-equal-bg);
    color: var(--btn-equal-text);
    font-size: 2rem;
    font-weight: 500;
    border: none;
    box-shadow: 0 8px 20px rgba(56, 189, 248, 0.3);
}

.btn-zero {
    grid-column: span 2;
    border-radius: 16px;
    justify-content: flex-start;
    padding-left: 25px;
}

/* Responsive adjust */
@media (max-width: 720px) {
    .calculator.scientific-mode {
        width: 100%;
        max-width: 360px;
    }
    
    .calculator.scientific-mode .keypad-wrapper {
        flex-direction: column;
        overflow-y: auto;
        max-height: 400px;
        padding-right: 5px;
    }
    
    .calculator.scientific-mode .scientific-keypad,
    .calculator.scientific-mode .basic-keypad {
        width: 100%;
    }
}

@media (max-width: 400px) {
    .calculator {
        width: 100%;
        max-width: 320px;
        padding: 25px 15px;
    }
    
    .btn {
        height: 50px;
        font-size: 1.2rem;
    }
    
    .btn-sci {
        font-size: 1rem;
    }
}

/* App Navigation */
.app-nav {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    padding: 5px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 15px;
    overflow-x: auto;
}

.nav-btn {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    padding: 8px 15px;
    border-radius: 10px;
    cursor: pointer;
    font-weight: 500;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.nav-btn.active {
    background: var(--calc-accent);
    color: white;
}

.calc-view {
    display: none;
    flex-direction: column;
    animation: fadeIn 0.3s ease;
}

.calc-view.active {
    display: flex;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Custom Inputs for new calculators */
.calc-header {
    text-align: center;
    margin-bottom: 20px;
}

.calc-header h2 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.calc-header p {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

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

.input-group label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    padding-left: 5px;
}

.custom-input {
    background: var(--btn-bg);
    border: 1px solid var(--calc-border);
    padding: 12px 15px;
    border-radius: 12px;
    color: var(--text-primary);
    font-size: 1rem;
    font-family: 'Outfit', sans-serif;
    outline: none;
    transition: all 0.3s ease;
    width: 100%;
    min-width: 0;
}

/* Force light theme styling on options as requested */
select.custom-input option {
    background-color: #ffffff !important;
    color: #000000 !important;
}

.custom-input:focus {
    border-color: var(--calc-accent);
    box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.3);
}

.action-btn {
    background: var(--calc-accent);
    color: white;
    border: none;
    padding: 15px;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    margin-top: 10px;
    transition: all 0.3s ease;
    width: 100%;
}

.form-box {
    background: var(--btn-bg);
    border: 1px solid var(--calc-border);
    padding: 20px;
    border-radius: 15px;
    box-shadow: inset 0 2px 10px rgba(0, 0, 0, 0.05);
}

.action-btn:hover {
    filter: brightness(1.1);
    transform: translateY(-2px);
}

.action-btn:active {
    transform: translateY(1px);
}

.result-container {
    margin-top: 25px;
    padding: 20px;
    background: var(--btn-bg);
    border-radius: 15px;
    border: 1px solid var(--calc-border);
    text-align: center;
}

.bmi-score {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--calc-accent);
    margin-bottom: 5px;
}

.bmi-category {
    font-size: 1.1rem;
    font-weight: 500;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.bmi-scale {
    height: 8px;
    width: 100%;
    background: linear-gradient(to right, #3b82f6, #22c55e, #eab308, #ef4444);
    border-radius: 4px;
    position: relative;
    margin-top: 20px;
}

.bmi-marker {
    width: 12px;
    height: 12px;
    background: white;
    border-radius: 50%;
    position: absolute;
    top: 50%;
    transform: translate(-50%, -50%);
    box-shadow: 0 0 5px rgba(0,0,0,0.5);
    transition: left 0.5s ease;
}

.age-main {
    font-size: 1.2rem;
    font-weight: 500;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.age-main span {
    font-size: 1.8rem;
    font-weight: 600;
    color: var(--calc-accent);
}

.age-details p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin: 5px 0;
    display: flex;
    justify-content: space-between;
    padding: 0 20px;
}

.age-details span {
    color: var(--text-primary);
    font-weight: 500;
}

/* Dashboard Styles */
.dashboard-wrapper {
    width: 100%;
    min-height: 100vh;
    padding: 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    position: relative;
    z-index: 10;
}

.dashboard-header {
    text-align: center;
    margin-bottom: 15px;
    margin-top: 5px;
}

.dashboard-header h1 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 5px;
    background: linear-gradient(135deg, #22c55e, #3b82f6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.dashboard-header p {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 15px;
    width: 100%;
    max-width: 1400px;
    align-items: start;
}

.category-card {
    background: var(--calc-bg);
    border-radius: 15px;
    padding: 15px 20px;
    box-shadow: var(--calc-shadow);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--calc-border);
    transition: transform 0.3s ease;
}

.category-card:hover {
    transform: translateY(-5px);
}

.category-header {
    display: flex;
    flex-direction: column;
    align-items: center;
    cursor: pointer;
    position: relative;
}

.expand-icon {
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-secondary);
    transition: transform 0.3s ease;
}

.category-card.expanded .expand-icon {
    transform: translateY(-50%) rotate(180deg);
}

.category-icon {
    font-size: 1.8rem;
    margin-bottom: 10px;
    display: flex;
    justify-content: center;
}

.category-title {
    font-size: 1.1rem;
    font-weight: 600;
    text-align: center;
    margin-bottom: 0; /* remove bottom margin since header handles it or we use margin-top for list */
}

.calculator-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 2px;
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    transition: max-height 0.4s ease, opacity 0.4s ease, margin-top 0.4s ease;
}

.category-card.expanded .calculator-list {
    max-height: 1000px;
    opacity: 1;
    margin-top: 15px;
}

.calculator-list li a {
    display: block;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.85rem;
    padding: 4px 8px;
    border-radius: 6px;
    transition: all 0.2s ease;
}

.calculator-list li a:hover {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
    padding-left: 18px;
}

.calculator-list li a.active-link {
    color: #38bdf8;
    font-weight: 500;
}

.calculator-list li a.active-link:hover {
    color: #0ea5e9;
}

/* App-like Page Transitions (Snappy Fade) */
@keyframes pageEnter {
    0% { 
        opacity: 0; 
        transform: translateY(8px); 
    }
    100% { 
        opacity: 1; 
        transform: translateY(0); 
    }
}

@keyframes pageExit {
    0% { 
        opacity: 1; 
    }
    100% { 
        opacity: 0; 
    }
}

.dashboard-wrapper, .calculator-wrapper {
    animation: pageEnter 0.25s ease-out forwards;
}

.page-exit {
    animation: pageExit 0.15s ease-in forwards !important;
    pointer-events: none;
}

/* Responsive Dashboard Layout */
@media (max-width: 1200px) {
    .dashboard-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 900px) {
    .dashboard-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 600px) {
    .dashboard-grid {
        grid-template-columns: 1fr;
    }
    
    .dashboard-header h1 {
        font-size: 1.6rem;
    }
    
    .search-container {
        padding: 0 5px;
    }
    
    .dashboard-wrapper, .calculator-wrapper {
        padding: 15px 10px;
    }
    
    .form-box {
        padding: 15px;
    }
    
    .calc-header h2 {
        font-size: 1.3rem;
    }
    
    .action-btn {
        padding: 12px;
        font-size: 1rem;
    }
    
    /* Ensure flex rows wrap on very small screens if they have gap */
    #inputs-base-height, #inputs-3-sides, .form-box > div[style*="display: flex"] {
        flex-direction: column !important;
        align-items: stretch !important;
    }
    
    .form-box > div[style*="display: flex"] > div,
    .form-box > div[style*="display: flex"] > select,
    .form-box > div[style*="display: flex"] > input {
        width: 100% !important;
    }
}