/* ===== CSS Reset & Base ===== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Futuristic Color Palette */
    --primary-cyan: #00f0ff;
    --primary-magenta: #ff00ff;
    --primary-purple: #8b5cf6;
    --primary-blue: #3b82f6;
    --neon-green: #39ff14;
    --neon-red: #ff3131;
    
    /* Background Colors */
    --bg-dark: #0a0a0f;
    --bg-card: rgba(15, 15, 25, 0.8);
    --bg-input: rgba(20, 20, 35, 0.6);
    
    /* Text Colors */
    --text-primary: #ffffff;
    --text-secondary: #a0a0b0;
    --text-muted: #606070;
    
    /* Glow Effects */
    --glow-cyan: 0 0 20px rgba(0, 240, 255, 0.5);
    --glow-magenta: 0 0 20px rgba(255, 0, 255, 0.5);
    --glow-purple: 0 0 20px rgba(139, 92, 246, 0.5);
    
    /* Gradients */
    --gradient-border: linear-gradient(135deg, var(--primary-cyan), var(--primary-purple), var(--primary-magenta));
    --gradient-btn: linear-gradient(135deg, var(--primary-cyan), var(--primary-blue));
    --gradient-btn-delete: linear-gradient(135deg, #ff416c, #ff4b2b);
    
    /* Typography */
    --font-display: 'Orbitron', sans-serif;
    --font-body: 'Rajdhani', sans-serif;
}

html {
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
    touch-action: manipulation;
}

body {
    font-family: var(--font-body);
    background: var(--bg-dark);
    color: var(--text-primary);
    min-height: 100vh;
    overflow-x: hidden;
    position: relative;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ===== Animated Background ===== */
.background-animation {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
}

.grid {
    position: absolute;
    top: 0;
    left: 0;
    width: 200%;
    height: 200%;
    background-image: 
        linear-gradient(rgba(0, 240, 255, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 240, 255, 0.03) 1px, transparent 1px);
    background-size: 50px 50px;
    animation: gridMove 20s linear infinite;
    transform: perspective(500px) rotateX(60deg);
    transform-origin: center top;
}

@keyframes gridMove {
    0% { transform: perspective(500px) rotateX(60deg) translateY(0); }
    100% { transform: perspective(500px) rotateX(60deg) translateY(50px); }
}

.particles {
    position: absolute;
    width: 100%;
    height: 100%;
}

.particles::before,
.particles::after {
    content: '';
    position: absolute;
    border-radius: 50%;
    filter: blur(60px);
    animation: float 15s ease-in-out infinite;
}

.particles::before {
    width: 400px;
    height: 400px;
    background: var(--primary-purple);
    top: 10%;
    left: 10%;
    opacity: 0.3;
}

.particles::after {
    width: 300px;
    height: 300px;
    background: var(--primary-cyan);
    bottom: 10%;
    right: 10%;
    opacity: 0.3;
    animation-delay: -5s;
}

@keyframes float {
    0%, 100% { transform: translate(0, 0) scale(1); }
    33% { transform: translate(30px, -30px) scale(1.1); }
    66% { transform: translate(-20px, 20px) scale(0.9); }
}

/* ===== Container ===== */
.container {
    max-width: 600px;
    margin: 0 auto;
    padding: 100px 20px 40px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

/* ===== Navigation Tabs ===== */
.nav-tabs {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
    justify-content: center;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(10, 10, 15, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    padding: 15px 20px;
    border-bottom: 1px solid rgba(0, 240, 255, 0.2);
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.5);
}

.nav-tab {
    position: relative;
    padding: 12px 24px;
    background: transparent;
    border: 1px solid rgba(0, 240, 255, 0.3);
    border-radius: 8px;
    cursor: pointer;
    overflow: hidden;
    transition: all 0.3s ease;
    min-height: 44px;
}

.nav-tab .tab-glow {
    position: absolute;
    inset: 0;
    background: var(--gradient-border);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.nav-tab .tab-text {
    position: relative;
    font-family: var(--font-display);
    font-size: 0.85rem;
    font-weight: 500;
    letter-spacing: 2px;
    color: var(--text-secondary);
    transition: color 0.3s ease;
    white-space: nowrap;
}

.nav-tab:hover {
    border-color: var(--primary-cyan);
    box-shadow: var(--glow-cyan);
}

.nav-tab:hover .tab-text {
    color: var(--text-primary);
}

/* Style for nav-tab as link */
a.nav-tab {
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.nav-tab.active {
    border-color: transparent;
}

.nav-tab.active .tab-glow {
    opacity: 1;
}

.nav-tab.active .tab-text {
    color: var(--bg-dark);
    font-weight: 600;
}

/* ===== Calculator Card ===== */
.calculator-card {
    position: relative;
    width: 100%;
    background: var(--bg-card);
    border-radius: 20px;
    padding: 40px;
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
}

.card-border {
    position: absolute;
    inset: 0;
    border-radius: 20px;
    padding: 1px;
    background: var(--gradient-border);
    -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
    mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
    -webkit-mask-composite: xor;
    mask-composite: exclude;
    animation: borderRotate 4s linear infinite;
    pointer-events: none;
}

@keyframes borderRotate {
    0% { filter: hue-rotate(0deg); }
    100% { filter: hue-rotate(360deg); }
}

.card-glow {
    position: absolute;
    inset: -2px;
    border-radius: 22px;
    background: var(--gradient-border);
    filter: blur(30px);
    opacity: 0.3;
    z-index: -1;
    animation: borderRotate 4s linear infinite;
}

/* ===== Card Header ===== */
.card-header {
    text-align: center;
    margin-bottom: 35px;
}

.title {
    font-family: var(--font-display);
    font-size: 2.5rem;
    font-weight: 900;
    letter-spacing: 4px;
    margin-bottom: 10px;
    position: relative;
}

.title-glitch {
    position: relative;
    display: inline-block;
    background: var(--gradient-border);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: glitch 3s infinite;
}

.title-glitch::before,
.title-glitch::after {
    content: attr(data-text);
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--gradient-border);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.title-glitch::before {
    animation: glitch-1 2s infinite linear alternate-reverse;
    clip-path: polygon(0 0, 100% 0, 100% 35%, 0 35%);
}

.title-glitch::after {
    animation: glitch-2 3s infinite linear alternate-reverse;
    clip-path: polygon(0 65%, 100% 65%, 100% 100%, 0 100%);
}

@keyframes glitch {
    0%, 90%, 100% { transform: translate(0); }
    92% { transform: translate(-2px, 2px); }
    94% { transform: translate(2px, -2px); }
    96% { transform: translate(-2px, -2px); }
    98% { transform: translate(2px, 2px); }
}

@keyframes glitch-1 {
    0%, 100% { transform: translate(0); }
    20% { transform: translate(-3px, 0); }
    40% { transform: translate(3px, 0); }
    60% { transform: translate(-3px, 0); }
    80% { transform: translate(3px, 0); }
}

@keyframes glitch-2 {
    0%, 100% { transform: translate(0); }
    20% { transform: translate(3px, 0); }
    40% { transform: translate(-3px, 0); }
    60% { transform: translate(3px, 0); }
    80% { transform: translate(-3px, 0); }
}

.subtitle {
    font-size: 1rem;
    color: var(--text-secondary);
    letter-spacing: 6px;
    text-transform: uppercase;
    font-weight: 300;
}

/* ===== Calculator Form ===== */
.calculator-form {
    display: flex;
    flex-direction: column;
    gap: 25px;
}

.input-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.input-row.full-width {
    grid-template-columns: 1fr;
}

.button-row.full-width {
    grid-template-columns: 1fr 1fr;
}

/* ===== Payment Gateway Checkbox ===== */
.checkbox-wrapper {
    display: none;
    justify-content: flex-start;
}

.slip-row {
    display: none;
    align-items: center;
    gap: 12px;
}

.fee-type-row {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
}

.slip-label {
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 600;
    letter-spacing: 0.5px;
    color: var(--text-primary);
}

.slip-select-wrapper {
    flex: 1;
    max-width: 260px;
}

.checkbox-label {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 10px 15px;
    background: var(--bg-input);
    border: 1px solid rgba(0, 240, 255, 0.2);
    border-radius: 10px;
    cursor: pointer;
    user-select: none;
    transition: all 0.3s ease;
}

.checkbox-label:hover {
    border-color: var(--primary-cyan);
    box-shadow: var(--glow-cyan);
}

.checkbox-label input[type="checkbox"] {
    display: none;
}

.checkbox-box {
    width: 20px;
    height: 20px;
    border: 2px solid var(--primary-cyan);
    border-radius: 5px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    transition: all 0.3s ease;
}

.checkbox-box::after {
    content: '';
    width: 10px;
    height: 10px;
    background: var(--neon-green);
    border-radius: 2px;
    transform: scale(0);
    transition: transform 0.2s ease;
}

.checkbox-label input[type="checkbox"]:checked + .checkbox-box {
    border-color: var(--neon-green);
    box-shadow: 0 0 10px rgba(57, 255, 20, 0.5);
}

.checkbox-label input[type="checkbox"]:checked + .checkbox-box::after {
    transform: scale(1);
}

.checkbox-text {
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 600;
    letter-spacing: 0.5px;
    text-transform: uppercase;
    color: var(--text-primary);
}

/* ===== Input Wrappers ===== */
.input-wrapper {
    position: relative;
}

.select-wrapper {
    position: relative;
}

/* ===== Futuristic Select ===== */
.futuristic-select {
    width: 100%;
    padding: 15px 40px 15px 15px;
    background: var(--bg-input);
    border: 1px solid rgba(0, 240, 255, 0.2);
    border-radius: 10px;
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    appearance: none;
    transition: all 0.3s ease;
    min-height: 50px;
}

.futuristic-select:focus {
    outline: none;
    border-color: var(--primary-cyan);
    box-shadow: var(--glow-cyan);
}

.select-arrow {
    position: absolute;
    right: 15px;
    top: 50%;
    transform: translateY(-50%);
    width: 20px;
    height: 20px;
    color: var(--primary-cyan);
    pointer-events: none;
}

/* ===== Futuristic Input ===== */
.futuristic-input {
    width: 100%;
    padding: 15px;
    background: var(--bg-input);
    border: 1px solid rgba(0, 240, 255, 0.2);
    border-radius: 10px;
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 500;
    transition: all 0.3s ease;
    min-height: 50px;
}

.futuristic-input::placeholder {
    color: var(--text-muted);
}

.futuristic-input:focus {
    outline: none;
    border-color: var(--primary-cyan);
    box-shadow: var(--glow-cyan);
}

.input-label {
    position: absolute;
    left: 15px;
    top: -10px;
    padding: 0 8px;
    background: var(--bg-card);
    color: var(--primary-cyan);
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 1px;
    text-transform: uppercase;
    opacity: 0;
    transform: translateY(5px);
    transition: all 0.3s ease;
}

.futuristic-input:focus + .input-label,
.futuristic-input:not(:placeholder-shown) + .input-label {
    opacity: 1;
    transform: translateY(0);
}

.input-glow {
    position: absolute;
    inset: 0;
    border-radius: 10px;
    background: var(--primary-cyan);
    filter: blur(20px);
    opacity: 0;
    transition: opacity 0.3s ease;
    z-index: -1;
}

.futuristic-input:focus ~ .input-glow,
.futuristic-select:focus ~ .input-glow {
    opacity: 0.2;
}

/* ===== Buttons ===== */
.button-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
    margin-top: 10px;
}

.btn {
    position: relative;
    padding: 16px 24px;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    transition: all 0.3s ease;
    min-height: 50px;
    -webkit-tap-highlight-color: transparent;
}

.btn-glow {
    position: absolute;
    inset: 0;
    opacity: 0.8;
    transition: all 0.3s ease;
}

.btn-text {
    position: relative;
    font-family: var(--font-display);
    font-size: 0.9rem;
    font-weight: 600;
    letter-spacing: 2px;
}

.btn-icon {
    position: relative;
    width: 20px;
    height: 20px;
}

.btn-calculate {
    background: var(--gradient-btn);
}

.btn-calculate .btn-glow {
    background: var(--gradient-btn);
    filter: blur(20px);
}

.btn-calculate:hover {
    transform: translateY(-2px);
}

.btn-calculate:hover .btn-glow {
    opacity: 1;
    filter: blur(30px);
}

.btn-delete {
    background: var(--gradient-btn-delete);
}

.btn-delete .btn-glow {
    background: var(--gradient-btn-delete);
    filter: blur(20px);
}

.btn-delete:hover {
    transform: translateY(-2px);
}

.btn-delete:hover .btn-glow {
    opacity: 1;
    filter: blur(30px);
}

.btn:active {
    transform: translateY(0) scale(0.98);
}

/* ===== Result Container ===== */
.result-container {
    position: relative;
    margin-top: 30px;
    padding: 25px;
    background: rgba(0, 240, 255, 0.05);
    border-radius: 15px;
    border: 1px solid rgba(0, 240, 255, 0.2);
    overflow: hidden;
}

.result-border {
    position: absolute;
    inset: 0;
    border-radius: 15px;
    padding: 1px;
    background: linear-gradient(90deg, transparent, var(--primary-cyan), transparent);
    -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
    mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
    -webkit-mask-composite: xor;
    mask-composite: exclude;
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}

.result-content {
    position: relative;
    text-align: center;
}

.result-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    letter-spacing: 3px;
    margin-bottom: 10px;
}

.result-value-wrapper {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    flex-wrap: wrap;
}

.result-value {
    font-family: var(--font-display);
    font-size: 1.8rem;
    font-weight: 700;
    background: var(--gradient-border);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: borderRotate 4s linear infinite;
    word-break: break-all;
}

.result-details {
    margin-top: 10px;
    font-size: 0.9rem;
    color: var(--text-secondary);
    word-break: break-word;
}

/* ===== Copy Button ===== */
.btn-copy {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 14px;
    background: rgba(0, 240, 255, 0.1);
    border: 1px solid rgba(0, 240, 255, 0.3);
    border-radius: 8px;
    color: var(--primary-cyan);
    cursor: pointer;
    transition: all 0.3s ease;
    min-height: 36px;
    -webkit-tap-highlight-color: transparent;
}

.btn-copy:hover {
    background: rgba(0, 240, 255, 0.2);
    border-color: var(--primary-cyan);
    box-shadow: var(--glow-cyan);
}

.btn-copy:active {
    transform: scale(0.95);
}

.btn-copy.copied {
    background: rgba(57, 255, 20, 0.2);
    border-color: var(--neon-green);
    color: var(--neon-green);
}

.copy-icon {
    width: 16px;
    height: 16px;
}

.copy-text {
    font-family: var(--font-display);
    font-size: 0.7rem;
    font-weight: 600;
    letter-spacing: 1px;
}

.copy-toast {
    position: absolute;
    bottom: 10px;
    left: 50%;
    transform: translateX(-50%) translateY(20px);
    padding: 8px 16px;
    background: var(--neon-green);
    color: var(--bg-dark);
    border-radius: 8px;
    font-family: var(--font-display);
    font-size: 0.8rem;
    font-weight: 600;
    opacity: 0;
    pointer-events: none;
    transition: all 0.3s ease;
    z-index: 10;
}

.copy-toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

/* ===== Footer ===== */
.footer {
    margin-top: 40px;
    text-align: center;
}

.footer-line {
    width: 100px;
    height: 2px;
    background: var(--gradient-border);
    margin: 0 auto 20px;
    animation: borderRotate 4s linear infinite;
}

.footer-text {
    font-size: 0.85rem;
    color: var(--text-muted);
    letter-spacing: 2px;
}

.footer-copyright {
    font-weight: 500;
}

.footer-separator {
    margin: 0 10px;
    color: var(--primary-cyan);
}

.footer-tagline {
    font-style: italic;
}

/* ===== Scrollbar ===== */
::-webkit-scrollbar {
    width: 6px;
}

::-webkit-scrollbar-track {
    background: var(--bg-dark);
}

::-webkit-scrollbar-thumb {
    background: var(--primary-cyan);
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-purple);
}

/* ===== Selection ===== */
::selection {
    background: var(--primary-cyan);
    color: var(--bg-dark);
}

/* ===== MOBILE RESPONSIVE ===== */
@media (max-width: 768px) {
    html {
        font-size: 14px;
    }
    
    .container {
        padding: 90px 15px 20px;
        justify-content: flex-start;
    }
    
    .nav-tabs {
        gap: 10px;
        padding: 12px 15px;
    }
    
    .nav-tab {
        padding: 10px 16px;
        min-height: 40px;
    }
    
    .nav-tab .tab-text {
        font-size: 0.7rem;
        letter-spacing: 1px;
    }
    
    .calculator-card {
        padding: 25px 20px;
        border-radius: 16px;
    }
    
    .card-header {
        margin-bottom: 25px;
    }
    
    .title {
        font-size: 1.8rem;
        letter-spacing: 2px;
    }
    
    .subtitle {
        font-size: 0.8rem;
        letter-spacing: 3px;
    }
    
    .input-row {
        grid-template-columns: 1fr;
        gap: 12px;
    }
    
    .futuristic-select,
    .futuristic-input {
        padding: 12px 35px 12px 12px;
        font-size: 16px; /* Prevents iOS zoom */
        min-height: 48px;
    }
    
    .futuristic-input {
        padding: 12px;
    }
    
    .input-label {
        font-size: 0.65rem;
        top: -8px;
    }
    
    .button-row {
        gap: 10px;
        margin-top: 5px;
    }
    
    .btn {
        padding: 14px 16px;
        min-height: 48px;
    }
    
    .btn-text {
        font-size: 0.8rem;
        letter-spacing: 1px;
    }
    
    .btn-icon {
        width: 18px;
        height: 18px;
    }
    
    .result-container {
        margin-top: 20px;
        padding: 20px 15px;
    }
    
    .result-value-wrapper {
        flex-direction: column;
        gap: 10px;
    }
    
    .result-value {
        font-size: 1.4rem;
    }
    
    .result-details {
        font-size: 0.85rem;
    }
    
    .btn-copy {
        padding: 6px 12px;
    }
    
    .footer {
        margin-top: 30px;
    }
    
    .footer-text {
        font-size: 0.75rem;
    }
}

@media (max-width: 380px) {
    .title {
        font-size: 1.5rem;
    }
    
    .nav-tab {
        padding: 8px 12px;
    }
    
    .nav-tab .tab-text {
        font-size: 0.6rem;
    }
    
    .btn-text {
        font-size: 0.7rem;
    }
    
    .result-value {
        font-size: 1.2rem;
    }
}

/* Safe area for notched phones */
@supports (padding: max(0px)) {
    .container {
        padding-left: max(15px, env(safe-area-inset-left));
        padding-right: max(15px, env(safe-area-inset-right));
        padding-bottom: max(20px, env(safe-area-inset-bottom));
    }
}