// ─── Game rules ──────────────────────────────────────────────────────────────
const MAX_DOCKS        = 6;     // failed docks before game over
const NUM_ANCHORS      = 6;     // anchor points around the central molecule
const ANCHOR_RADIUS    = 120;   // px distance from center to anchor points
const CLICK_RADIUS     = 38;    // px hit radius for clicking an anchor

// ─── Spawn timing ────────────────────────────────────────────────────────────
const SPAWN_INTERVAL_START = 2500;  // ms between spawns at the start
const SPAWN_INTERVAL_MIN   = 700;   // ms floor (fastest difficulty)
const SPAWN_DIFFICULTY_STEP = 18;   // ms reduction per spawn

// ─── Incoming atom ───────────────────────────────────────────────────────────
const ATOM_SPEED_MIN   = 1.4;   // px/frame minimum
const ATOM_SPEED_MAX   = 3.2;   // px/frame maximum (min + random range)
const ATOM_RADIUS_MIN  = 16;    // px nucleus radius minimum
const ATOM_RADIUS_MAX  = 24;    // px nucleus radius maximum (min + random range)
const ATOM_HUE_MIN     = 180;   // hsl hue range start (blue-cyan)
const ATOM_HUE_RANGE   = 60;    // hsl hue range width
const ATOM_ELECTRON_SPEED_MIN  = 0.05;
const ATOM_ELECTRON_SPEED_MAX  = 0.08;

// ─── Particles ───────────────────────────────────────────────────────────────
const BURST_COUNT      = 20;    // particles per burst
const BURST_SPEED_MIN  = 2;
const BURST_SPEED_MAX  = 7;
const PARTICLE_DECAY_MIN = 0.022;
const PARTICLE_DECAY_MAX = 0.047;
const PARTICLE_RADIUS_MIN = 2;
const PARTICLE_RADIUS_MAX = 6;

// ─── Anchor block flash ───────────────────────────────────────────────────────
const BLOCK_TIMER_FRAMES = 20;  // frames the green flash lasts after a block

// ─── Stars ───────────────────────────────────────────────────────────────────
const STAR_COUNT       = 160;
const STAR_ALPHA_MIN   = 0.15;
const STAR_ALPHA_RANGE = 0.55;
const STAR_RADIUS_MAX  = 1.5;

// ─── Central nucleus ─────────────────────────────────────────────────────────
const NUCLEUS_RADIUS   = 52;    // px
const NUCLEUS_ORBITS   = 3;     // electron orbits to draw

// ─── Cystinstein indicator ────────────────────────────────────────────────────
const CYS_CENTER_X     = 65;    // px within the 130×130 side canvas
const CYS_CENTER_Y     = 65;
const CYS_CORE_RADIUS  = 14;    // central atom radius
const CYS_DOCK_RADIUS  = 28;    // distance from center to docked atoms
const CYS_ATOM_RADIUS  = 9;     // docked atom radius
const CYS_RING_RADIUS  = 48;    // final danger ring radius