:root {
    --bg-base: #020617;
    --bg-glass: rgba(15, 23, 42, 0.6);
    --bg-card: rgba(30, 41, 59, 0.7);
    --text-primary: #F8FAFC;
    --text-secondary: #94A3B8;
    --accent-blue: #3B82F6;
    --accent-cyan: #0EA5E9;
    --accent-green: #10B981;
    --accent-red: #EF4444;
    --border-light: rgba(255, 255, 255, 0.08);
    --border-glow: rgba(59, 130, 246, 0.5);
    
    --shadow-neumorphic: 4px 4px 10px rgba(0,0,0,0.5), -4px -4px 10px rgba(255,255,255,0.02);
    --shadow-inset: inset 4px 4px 15px rgba(0,0,0,0.8), inset -4px -4px 15px rgba(255,255,255,0.03);
    --shadow-glow: 0 0 20px rgba(16, 185, 129, 0.4);
    
    --radius-sm: 8px;
    --radius-md: 16px;
    --radius-lg: 24px;
    --radius-pill: 9999px;
    
    --transition: all 0.25s cubic-bezier(0.25, 0.8, 0.25, 1);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Outfit', sans-serif;
    background-color: var(--bg-base);
    color: var(--text-primary);
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

/* Animated Background Orbs */
.bg-orbs {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    z-index: -1;
    overflow: hidden;
    background: #020617;
}

.orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(100px);
    opacity: 0.5;
    animation: float 20s infinite ease-in-out alternate;
}

.orb-1 {
    width: 400px; height: 400px;
    background: #1e1b4b; /* deep violet */
    top: -100px; left: -100px;
}

.orb-2 {
    width: 350px; height: 350px;
    background: #064e3b; /* emerald dark */
    bottom: -100px; right: -50px;
    animation-delay: -5s;
}

.orb-3 {
    width: 300px; height: 300px;
    background: #0c4a6e; /* sky dark */
    top: 40%; left: 30%;
    animation-delay: -10s;
}

@keyframes float {
    0% { transform: translate(0, 0) scale(1); }
    100% { transform: translate(50px, 80px) scale(1.2); }
}

/* App Container */
.app-container {
    width: 100%;
    max-width: 460px;
    height: 100vh;
    display: flex;
    flex-direction: column;
    background: var(--bg-glass);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border-left: 1px solid var(--border-light);
    border-right: 1px solid var(--border-light);
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    position: relative;
    overflow-y: auto;
    overflow-x: hidden;
}

@media (min-width: 480px) {
    .app-container {
        height: 95vh;
        border-radius: 32px;
        border: 1px solid var(--border-light);
    }
}

/* Header */
.app-header {
    padding: 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-light);
    position: sticky;
    top: 0;
    z-index: 10;
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(12px);
}

.app-header h1 {
    font-size: 26px;
    font-weight: 800;
    letter-spacing: -0.5px;
    background: linear-gradient(135deg, #fff 0%, #94a3b8 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.highlight {
    background: linear-gradient(135deg, var(--accent-cyan) 0%, var(--accent-blue) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

nav {
    display: flex;
    gap: 6px;
    background: rgba(0, 0, 0, 0.3);
    padding: 4px;
    border-radius: var(--radius-pill);
    border: 1px solid var(--border-light);
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.3);
}

.nav-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    padding: 8px 16px;
    border-radius: var(--radius-pill);
    font-size: 13px;
    font-weight: 700;
    cursor: pointer;
    transition: var(--transition);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.nav-btn.active {
    background: linear-gradient(135deg, var(--bg-card) 0%, rgba(255,255,255,0.05) 100%);
    color: var(--text-primary);
    box-shadow: 0 4px 10px rgba(0,0,0,0.3);
    border: 1px solid rgba(255,255,255,0.1);
}

/* Views */
.view {
    display: none;
    flex: 1;
    padding: 24px;
    flex-direction: column;
    gap: 24px;
    animation: fadeIn 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

.view.active {
    display: flex;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(15px) scale(0.98); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}

/* Hardware-Style Result Display */
.result-display {
    background: #050b14;
    border: 2px solid #1e293b;
    border-radius: var(--radius-lg);
    padding: 24px;
    text-align: right;
    box-shadow: var(--shadow-inset);
    position: relative;
    overflow: hidden;
}

.result-display::after {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; height: 40%;
    background: linear-gradient(180deg, rgba(255,255,255,0.03) 0%, transparent 100%);
    pointer-events: none;
}

.result-label {
    font-size: 11px;
    font-weight: 800;
    color: rgba(16, 185, 129, 0.7);
    letter-spacing: 2px;
    margin-bottom: 8px;
    text-transform: uppercase;
}

.result-value {
    font-size: 52px;
    font-weight: 300;
    color: var(--accent-green);
    line-height: 1.1;
    letter-spacing: -2px;
    text-shadow: 0 0 15px rgba(16, 185, 129, 0.6);
    transition: var(--transition);
    font-family: monospace;
}

.result-display.updated .result-value {
    color: #fff;
    text-shadow: 0 0 25px rgba(255, 255, 255, 0.8);
}

/* Configuration Section */
.config-section {
    display: flex;
    flex-direction: column;
    gap: 16px;
    background: var(--bg-card);
    padding: 20px;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-light);
    box-shadow: var(--shadow-neumorphic);
}

.form-group label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 10px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.select-wrapper {
    position: relative;
}

.select-wrapper::after {
    content: '▼';
    position: absolute;
    right: 16px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--accent-blue);
    font-size: 12px;
    pointer-events: none;
}

.select-wrapper select {
    width: 100%;
    appearance: none;
    background: rgba(0,0,0,0.3);
    border: 1px solid var(--border-light);
    color: var(--text-primary);
    padding: 16px;
    border-radius: var(--radius-md);
    font-size: 16px;
    font-weight: 500;
    outline: none;
    transition: var(--transition);
    cursor: pointer;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.5);
}

.select-wrapper select:focus {
    border-color: var(--accent-cyan);
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.5), 0 0 0 2px rgba(14, 165, 233, 0.2);
}

.chip-group {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.chip {
    flex: 1;
    min-width: 50px;
    background: rgba(0,0,0,0.2);
    border: 1px solid rgba(255,255,255,0.05);
    color: var(--text-secondary);
    padding: 12px 0;
    border-radius: var(--radius-md);
    font-size: 15px;
    font-weight: 700;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 2px 2px 5px rgba(0,0,0,0.2);
}

.chip:hover {
    background: rgba(255,255,255,0.05);
    color: var(--text-primary);
}

.chip.active {
    background: linear-gradient(135deg, var(--accent-blue) 0%, var(--accent-cyan) 100%);
    color: white;
    border-color: transparent;
    box-shadow: 0 4px 15px rgba(14, 165, 233, 0.4);
    transform: translateY(-2px);
}

/* Fast Add Group */
.fast-add-group {
    display: flex;
    gap: 10px;
    overflow-x: auto;
    padding-bottom: 12px;
    margin-bottom: 8px;
}

.fast-add-group::-webkit-scrollbar {
    height: 4px;
}
.fast-add-group::-webkit-scrollbar-thumb {
    background: rgba(255,255,255,0.1);
    border-radius: var(--radius-pill);
}

.fast-add-btn {
    background: rgba(14, 165, 233, 0.1);
    border: 1px solid rgba(14, 165, 233, 0.3);
    color: var(--accent-cyan);
    padding: 10px 20px;
    border-radius: var(--radius-pill);
    font-size: 15px;
    font-weight: 700;
    cursor: pointer;
    white-space: nowrap;
    transition: var(--transition);
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
}

.fast-add-btn:hover {
    background: rgba(14, 165, 233, 0.2);
    transform: translateY(-2px);
    box-shadow: 0 4px 10px rgba(14, 165, 233, 0.3);
}

.fast-add-btn:active {
    transform: translateY(1px);
    box-shadow: none;
}

/* Amount & Numpad */
.amount-section {
    margin-top: auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.input-display {
    background: transparent;
    padding: 10px 16px;
    font-size: 42px;
    font-weight: 300;
    text-align: right;
    color: var(--text-primary);
    min-height: 60px;
    display: flex;
    align-items: center;
    justify-content: flex-end;
    overflow-x: auto;
    border-bottom: 1px solid rgba(255,255,255,0.1);
    letter-spacing: -1px;
}

.numpad {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 16px;
}

.num-btn {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
    font-size: 26px;
    font-weight: 500;
    aspect-ratio: 1 / 1;
    border-radius: 50%;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 4px 4px 10px rgba(0,0,0,0.3), inset 1px 1px 1px rgba(255,255,255,0.1);
    position: relative;
    overflow: hidden;
}

.num-btn::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: radial-gradient(circle at center, rgba(255,255,255,0.1) 0%, transparent 60%);
    opacity: 0;
    transition: opacity 0.2s;
}

.num-btn:hover::before {
    opacity: 1;
}

.num-btn:active {
    transform: scale(0.95);
    box-shadow: inset 2px 2px 5px rgba(0,0,0,0.5);
    background: rgba(0,0,0,0.2);
}

.op-btn {
    color: var(--accent-cyan);
    font-weight: 600;
    background: rgba(14, 165, 233, 0.05);
}

.equal-btn {
    background: #f97316;
    color: white;
    font-weight: 700;
    border: none;
    box-shadow: 0 8px 20px rgba(249, 115, 22, 0.3), inset 1px 1px 1px rgba(255,255,255,0.3);
}

.equal-btn:active {
    background: #ea580c;
    box-shadow: inset 2px 2px 10px rgba(0,0,0,0.3);
}

/* Settings View */
.view-title {
    font-size: 28px;
    font-weight: 800;
    margin-bottom: 8px;
    letter-spacing: -0.5px;
}

.settings-card {
    background: var(--bg-card);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-lg);
    padding: 24px;
    box-shadow: var(--shadow-neumorphic);
}

.settings-card h3 {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--accent-cyan);
    display: flex;
    align-items: center;
    gap: 8px;
}

.settings-card h3::before {
    content: '';
    width: 8px; height: 8px;
    background: var(--accent-cyan);
    border-radius: 50%;
    box-shadow: 0 0 10px var(--accent-cyan);
}

.add-form {
    display: flex;
    flex-direction: column;
    gap: 16px;
    margin-bottom: 20px;
}

.add-form input {
    background: rgba(0,0,0,0.3);
    border: 1px solid var(--border-light);
    color: var(--text-primary);
    padding: 16px;
    border-radius: var(--radius-md);
    font-family: inherit;
    font-size: 15px;
    outline: none;
    transition: var(--transition);
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.3);
}

.add-form input:focus {
    border-color: var(--accent-blue);
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.3), 0 0 0 2px rgba(59,130,246,0.2);
}

.primary-btn {
    background: linear-gradient(135deg, var(--accent-blue) 0%, var(--accent-cyan) 100%);
    color: white;
    border: none;
    padding: 16px;
    border-radius: var(--radius-md);
    font-size: 15px;
    font-weight: 700;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 4px 15px rgba(14, 165, 233, 0.3);
}

.primary-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(14, 165, 233, 0.4);
}

.primary-btn:active {
    transform: translateY(0);
}

.list-container {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.list-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: rgba(0,0,0,0.2);
    padding: 16px;
    border-radius: var(--radius-md);
    border: 1px solid rgba(255,255,255,0.03);
    transition: var(--transition);
}

.list-item:hover {
    background: rgba(255,255,255,0.05);
    border-color: rgba(255,255,255,0.1);
}

.list-item-info strong {
    display: block;
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 4px;
}
.list-item-info span {
    font-size: 13px;
    color: var(--text-secondary);
}

.delete-btn {
    background: rgba(239,68,68,0.1);
    color: var(--accent-red);
    border: 1px solid rgba(239,68,68,0.2);
    padding: 8px 14px;
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: 13px;
    font-weight: 700;
    transition: var(--transition);
}
.delete-btn:hover {
    background: var(--accent-red);
    color: white;
    box-shadow: 0 4px 10px rgba(239,68,68,0.3);
}

.edit-btn {
    background: rgba(59,130,246,0.1);
    color: var(--accent-cyan);
    border: 1px solid rgba(59,130,246,0.2);
    padding: 8px 14px;
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: 13px;
    font-weight: 700;
    transition: var(--transition);
    margin-right: 8px;
}
.edit-btn:hover {
    background: var(--accent-cyan);
    color: white;
    box-shadow: 0 4px 10px rgba(14,165,233,0.3);
}

.cat-units-selection {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 20px;
    max-height: 200px;
    overflow-y: auto;
    background: rgba(0,0,0,0.2);
    padding: 16px;
    border-radius: var(--radius-md);
    border: 1px solid rgba(255,255,255,0.03);
}

.cat-units-selection::-webkit-scrollbar { width: 6px; }
.cat-units-selection::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.1); border-radius: 10px; }

.checkbox-lbl {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 15px;
    font-weight: 500;
    cursor: pointer;
    color: var(--text-primary);
    padding: 8px;
    border-radius: var(--radius-sm);
    transition: var(--transition);
}

.checkbox-lbl:hover {
    background: rgba(255,255,255,0.05);
}

.checkbox-lbl input {
    accent-color: var(--accent-cyan);
    width: 20px;
    height: 20px;
    cursor: pointer;
}

/* Toast */
.toast {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--bg-card);
    color: var(--text-primary);
    padding: 16px 32px;
    border-radius: var(--radius-pill);
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
    border: 1px solid var(--border-light);
    font-size: 15px;
    font-weight: 600;
    opacity: 0;
    transition: all 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
    z-index: 1000;
    backdrop-filter: blur(10px);
}

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